Prior to this commit the entire amqp-value or amqp-sequence sections
were parsed when converting a message from mc_amqp.
Parsing the entire amqp-value or amqp-sequence section can generate a
huge amount of garbage depending on how large these sections are.
Given that other protocol cannot make use of amqp-value and
amqp-sequence sections anyway, leave them AMQP encoded when converting
from mc_amqp.
In fact prior to this commit, the entire body section was parsed
generating huge amounts of garbage just to subsequently encode it again
in mc_amqpl or mc_mqtt.
The new conversion interface from mc_amqp to other mc_* modules will
either output amqp-data sections or the encoded amqp-value /
amqp-sequence sections.
This commit fixes test
```
bazel test //deps/rabbitmq_mqtt:shared_SUITE-mixed -t- \
--test_sharding_strategy=disabled --test_env \
FOCUS="-group [mqtt,v3,cluster_size_3] -case pubsub"
```
Fix some mixed version tests
Assume the AMQP body, especially amqp-value section won't be parsed.
Hence, omit smart conversions from AMQP to MQTT involving the
Payload-Format-Indicator bit.
Fix test
Fix
```
bazel test //deps/amqp10_client:system_SUITE-mixed -t- --test_sharding_strategy=disabled --test_env FOCUS="-group [rabbitmq]
```
Resolves https://github.com/rabbitmq/rabbitmq-server/discussions/11021
Prior to this commit, an MQTT client that connects to RabbitMQ needed
configure access to its will queue even if the will queue has never
existed. This breaks client apps connecting with either v3 or v4 or with
v5 without making use of the Will-Delay-Interval.
Specifically, in 3.13.0 and 3.13.1 an MQTT client that connects to
RabbitMQ needs unnecessarily configure access to queue
`mqtt-will-<MQTT client ID>`.
This commit only check for configure access, if the queue actually gets
deleted, i.e. if it existed.
By default, when the 'durable' message container (mc) annotation is unset,
messages are interpreted to be durable.
Prior to this commit, MQTT messages that were sent with QoS 0 were
stored durably in classic queues.
This commit takes the same approach for mc_mqtt as for mc_amqpl and mc_amqp:
If the message is durable, the durable mc annotation will not be set.
If the message is non-durable, the durable mc annotation will be set to false.
When feature flag message_containers is enabled, setting
```
message_interceptors.incoming.set_header_timestamp
```
wasn't respected anymore when a message is published via MQTT to a
stream and subsequently consumed via AMQP 0.9.1.
This commit ensures that AMQP 0.9.1 header timestamp_in_ms will be
set.
Note that we must not modify the AMQP 1.0 properties section when messages
are received via AMQP 1.0 and consumed via AMQP 1.0.
Also, message annoation keys not starting with "x-" are reserved.
## What?
Introduce a new address format (let's call it v2) for AMQP 1.0 source and target addresses.
The old format (let's call it v1) is described in
https://github.com/rabbitmq/rabbitmq-server/tree/v3.13.x/deps/rabbitmq_amqp1_0#routing-and-addressing
The only v2 source address format is:
```
/queue/:queue
```
The 4 possible v2 target addresses formats are:
```
/exchange/:exchange/key/:routing-key
/exchange/:exchange
/queue/:queue
<null>
```
where the last AMQP <null> value format requires that each message’s `to` field contains one of:
```
/exchange/:exchange/key/:routing-key
/exchange/:exchange
/queue/:queue
```
## Why?
The AMQP address v1 format comes with the following flaws:
1. Obscure address format:
Without reading the documentation, the differences for example between source addresses
```
/amq/queue/:queue
/queue/:queue
:queue
```
are unknown to users. Hence, the address format is obscure.
2. Implicit creation of topologies
Some address formats implicitly create queues (and bindings), such as source address
```
/exchange/:exchange/:binding-key
```
or target address
```
/queue/:queue
```
These queues and bindings are never deleted (by the AMQP 1.0 plugin.)
Implicit creation of such topologies is also obscure.
3. Redundant address formats
```
/queue/:queue
:queue
```
have the same meaning and are therefore redundant.
4. Properties section must be parsed to determine whether a routing key is present
Target address
```
/exchange/:exchange
```
requires RabbitMQ to parse the properties section in order to check whether the message `subject` is set.
If `subject` is not set, the routing key will default to the empty string.
5. Using `subject` as routing key misuses the purpose of this field.
According to the AMQP spec, the message `subject` field's purpose is:
> A common field for summary information about the message content and purpose.
6. Exchange names, queue names and routing keys must not contain the "/" (slash) character.
The current 3.13 implemenation splits by "/" disallowing these
characters in exchange, and queue names, and routing keys which is
unnecessary prohibitive.
7. Clients must create a separate link per target exchange
While this is reasonable working assumption, there might be rare use
cases where it could make sense to create many exchanges (e.g. 1
exchange per queue, see
https://github.com/rabbitmq/rabbitmq-server/discussions/10708) and have
a single application publish to all these exchanges.
With the v1 address format, for an application to send to 500 different
exchanges, it needs to create 500 links.
Due to these disadvantages and thanks to #10559 which allows clients to explicitly create topologies,
we can create a simpler, clearer, and better v2 address format.
## How?
### Design goals
Following the 7 cons from v1, the design goals for v2 are:
1. The address format should be simple so that users have a chance to
understand the meaning of the address without necessarily consulting the docs.
2. The address format should not implicitly create queues, bindings, or exchanges.
Instead, topologies should be created either explicitly via the new management node
prior to link attachment (see #10559), or in future, we might support the `dynamic`
source or target properties so that RabbitMQ creates queues dynamically.
3. No redundant address formats.
4. The target address format should explicitly state whether the routing key is present, empty,
or will be provided dynamically in each message.
5. `Subject` should not be used as routing key. Instead, a better
fitting field should be used.
6. Exchange names, queue names, and routing keys should allow to contain
valid UTF-8 encoded data including the "/" character.
7. Allow both target exchange and routing key to by dynamically provided within each message.
Furthermore
8. v2 must co-exist with v1 for at least some time. Applications should be able to upgrade to
RabbitMQ 4.0 while continuing to use v1. Examples include AMQP 1.0 shovels and plugins communicating
between a 4.0 and a 3.13 cluster. Starting with 4.1, we should change the AMQP 1.0 shovel and plugin clients
to use only the new v2 address format. This will allow AMQP 1.0 and plugins to communicate between a 4.1 and 4.2 cluster.
We will deprecate v1 in 4.0 and remove support for v1 in a later 4.x version.
### Additional Context
The address is usually a String, but can be of any type.
The [AMQP Addressing extension](https://docs.oasis-open.org/amqp/addressing/v1.0/addressing-v1.0.html)
suggests that addresses are URIs and are therefore hierarchical and could even contain query parameters:
> An AMQP address is a URI reference as defined by RFC3986.
> the path expression is a sequence of identifier segments that reflects a path through an
> implementation specific relationship graph of AMQP nodes and their termini.
> The path expression MUST resolve to a node’s terminus in an AMQP container.
The [Using the AMQP Anonymous Terminus for Message Routing Version 1.0](https://docs.oasis-open.org/amqp/anonterm/v1.0/cs01/anonterm-v1.0-cs01.html)
extension allows for the target being `null` and the `To` property to contain the node address.
This corresponds to AMQP 0.9.1 where clients can send each message on the same channel to a different `{exchange, routing-key}` destination.
The following v2 address formats will be used.
### v2 addresses
A new deprecated feature flag `amqp_address_v1` will be introduced in 4.0 which is permitted by default.
Starting with 4.1, we should change the AMQP 1.0 shovel and plugin AMQP 1.0 clients to use only the new v2 address format.
However, 4.1 server code must still understand the 4.0 AMQP 1.0 shovel and plugin AMQP 1.0 clients’ v1 address format.
The new deprecated feature flag will therefore be denied by default in 4.2.
This allows AMQP 1.0 shovels and plugins to work between
* 4.0 and 3.13 clusters using v1
* 4.1 and 4.0 clusters using v2 from 4.1 to v4.0 and v1 from 4.0 to 4.1
* 4.2 and 4.1 clusters using v2
without having to support both v1 and v2 at the same time in the AMQP 1.0 shovel and plugin clients.
While supporting both v1 and v2 in these clients is feasible, it's simpler to switch the client code directly from v1 to v2.
### v2 source addresses
The source address format is
```
/queue/:queue
```
If the deprecated feature flag `amqp_address_v1` is permitted and the queue does not exist, the queue will be auto-created.
If the deprecated feature flag `amqp_address_v1` is denied, the queue must exist.
### v2 target addresses
v1 requires attaching a new link for each destination exchange.
v2 will allow dynamic `{exchange, routing-key}` combinations for a given link.
v2 therefore allows for the rare use cases where a single AMQP 1.0 publisher app needs to send to many different exchanges.
Setting up a link per destination exchange could be cumbersome.
Hence, v2 will support the dynamic `{exchange, routing-key}` combinations of AMQP 0.9.1.
To achieve this, we make use of the "Anonymous Terminus for Message Routing" extension:
The target address will contain the AMQP value null.
The `To` field in each message must be set and contain either address format
```
/exchange/:exchange/key/:routing-key
```
or
```
/exchange/:exchange
```
when using the empty routing key.
The `to` field requires an address type and is better suited than the `subject field.
Note that each message will contain this `To` value for the anonymous terminus.
Hence, we should save some bytes being sent across the network and stored on disk.
Using a format
```
/e/:exchange/k/:routing-key
```
saves more bytes, but is too obscure.
However, we use only `/key/` instead of `/routing-key/` so save a few bytes.
This also simplifies the format because users don’t have to remember whether to use spell `routing-key` or `routing_key` or `routingkey`.
The other allowed target address formats are:
```
/exchange/:exchange/key/:routing-key
```
where exchange and routing key are static on the given link.
```
/exchange/:exchange
```
where exchange and routing key are static on the given link, and routing key will be the empty string (useful for example for the fanout exchange).
```
/queue/:queue
```
This provides RabbitMQ beginners the illusion of sending a message directly
to a queue without having to understand what exchanges and routing keys are.
If the deprecated feature flag `amqp_address_v1` is permitted and the queue does not exist, the queue will be auto-created.
If the deprecated feature flag `amqp_address_v1` is denied, the queue must exist.
Besides the additional queue existence check, this queue target is different from
```
/exchange//key/:queue
```
in that queue specific optimisations might be done (in future) by RabbitMQ
(for example different receiving queue types could grant different amounts of link credits to the sending clients).
A write permission check to the amq.default exchange will be performed nevertheless.
v2 will prohibit the v1 static link & dynamic routing-key combination
where the routing key is sent in the message `subject` as that’s also obscure.
For this use case, v2’s new anonymous terminus can be used where both exchange and routing key are defined in the message’s `To` field.
(The bare message must not be modified because it could be signed.)
The alias format
```
/topic/:topic
```
will also be removed.
Sending to topic exchanges is arguably an advanced feature.
Users can directly use the format
```
/exchange/amq.topic/key/:topic
```
which reduces the number of redundant address formats.
### v2 address format reference
To sump up (and as stated at the top of this commit message):
The only v2 source address format is:
```
/queue/:queue
```
The 4 possible v2 target addresses formats are:
```
/exchange/:exchange/key/:routing-key
/exchange/:exchange
/queue/:queue
<null>
```
where the last AMQP <null> value format requires that each message’s `to` field contains one of:
```
/exchange/:exchange/key/:routing-key
/exchange/:exchange
/queue/:queue
```
Hence, all 8 listed design goals are reached.
PR #10761 added a new CLI command to list Web MQTT connections.
That new CLI command relies on feature flag delete_ra_cluster_mqtt_node
being enabled.
This commit ensures exactly this condition.
## What
Similar to Native MQTT in #5895, this commits implements Native AMQP 1.0.
By "native", we mean do not proxy via AMQP 0.9.1 anymore.
## Why
Native AMQP 1.0 comes with the following major benefits:
1. Similar to Native MQTT, this commit provides better throughput, latency,
scalability, and resource usage for AMQP 1.0.
See https://blog.rabbitmq.com/posts/2023/03/native-mqtt for native MQTT improvements.
See further below for some benchmarks.
2. Since AMQP 1.0 is not limited anymore by the AMQP 0.9.1 protocol,
this commit allows implementing more AMQP 1.0 features in the future.
Some features are already implemented in this commit (see next section).
3. Simpler, better understandable, and more maintainable code.
Native AMQP 1.0 as implemented in this commit has the
following major benefits compared to AMQP 0.9.1:
4. Memory and disk alarms will only stop accepting incoming TRANSFER frames.
New connections can still be created to consume from RabbitMQ to empty queues.
5. Due to 4. no need anymore for separate connections for publishers and
consumers as we currently recommended for AMQP 0.9.1. which potentially
halves the number of physical TCP connections.
6. When a single connection sends to multiple target queues, a single
slow target queue won't block the entire connection.
Publisher can still send data quickly to all other target queues.
7. A publisher can request whether it wants publisher confirmation on a per-message basis.
In AMQP 0.9.1 publisher confirms are configured per channel only.
8. Consumers can change their "prefetch count" dynamically which isn't
possible in our AMQP 0.9.1 implementation. See #10174
9. AMQP 1.0 is an extensible protocol
This commit also fixes dozens of bugs present in the AMQP 1.0 plugin in
RabbitMQ 3.x - most of which cannot be backported due to the complexity
and limitations of the old 3.x implementation.
This commit contains breaking changes and is therefore targeted for RabbitMQ 4.0.
## Implementation details
1. Breaking change: With Native AMQP, the behaviour of
```
Convert AMQP 0.9.1 message headers to application properties for an AMQP 1.0 consumer
amqp1_0.convert_amqp091_headers_to_app_props = false | true (default false)
Convert AMQP 1.0 Application Properties to AMQP 0.9.1 headers
amqp1_0.convert_app_props_to_amqp091_headers = false | true (default false)
```
will break because we always convert according to the message container conversions.
For example, AMQP 0.9.1 x-headers will go into message-annotations instead of application properties.
Also, `false` won’t be respected since we always convert the headers with message containers.
2. Remove rabbit_queue_collector
rabbit_queue_collector is responsible for synchronously deleting
exclusive queues. Since the AMQP 1.0 plugin never creates exclusive
queues, rabbit_queue_collector doesn't need to be started in the first
place. This will save 1 Erlang process per AMQP 1.0 connection.
3. 7 processes per connection + 1 process per session in this commit instead of
7 processes per connection + 15 processes per session in 3.x
Supervision hierarchy got re-designed.
4. Use 1 writer process per AMQP 1.0 connection
AMQP 0.9.1 uses a separate rabbit_writer Erlang process per AMQP 0.9.1 channel.
Prior to this commit, AMQP 1.0 used a separate rabbit_amqp1_0_writer process per AMQP 1.0 session.
Advantage of single writer proc per session (prior to this commit):
* High parallelism for serialising packets if multiple sessions within
a connection write heavily at the same time.
This commit uses a single writer process per AMQP 1.0 connection that is
shared across all AMQP 1.0 sessions.
Advantages of single writer proc per connection (this commit):
* Lower memory usage with hundreds of thousands of AMQP 1.0 sessions
* Less TCP and IP header overhead given that the single writer process
can accumulate across all sessions bytes before flushing the socket.
In other words, this commit decides that a reader / writer process pair
per AMQP 1.0 connection is good enough for bi-directional TRANSFER flows.
Having a writer per session is too heavy.
We still ensure high throughput by having separate reader, writer, and
session processes.
5. Transform rabbit_amqp1_0_writer into gen_server
Why:
Prior to this commit, when clicking on the AMQP 1.0 writer process in
observer, the process crashed.
Instead of handling all these debug messages of the sys module, it's better
to implement a gen_server.
There is no advantage of using a special OTP process over gen_server
for the AMQP 1.0 writer.
gen_server also provides cleaner format status output.
How:
Message callbacks return a timeout of 0.
After all messages in the inbox are processed, the timeout message is
handled by flushing any pending bytes.
6. Remove stats timer from writer
AMQP 1.0 connections haven't emitted any stats previously.
7. When there are contiguous queue confirmations in the session process
mailbox, batch them. When the confirmations are sent to the publisher, a
single DISPOSITION frame is sent for contiguously confirmed delivery
IDs.
This approach should be good enough. However it's sub optimal in
scenarios where contiguous delivery IDs that need confirmations are rare,
for example:
* There are multiple links in the session with different sender
settlement modes and sender publishes across these links interleaved.
* sender settlement mode is mixed and sender publishes interleaved settled
and unsettled TRANSFERs.
8. Introduce credit API v2
Why:
The AMQP 0.9.1 credit extension which is to be removed in 4.0 was poorly
designed since basic.credit is a synchronous call into the queue process
blocking the entire AMQP 1.0 session process.
How:
Change the interactions between queue clients and queue server
implementations:
* Clients only request a credit reply if the FLOW's `echo` field is set
* Include all link flow control state held by the queue process into a
new credit_reply queue event:
* `available` after the queue sends any deliveries
* `link-credit` after the queue sends any deliveries
* `drain` which allows us to combine the old queue events
send_credit_reply and send_drained into a single new queue event
credit_reply.
* Include the consumer tag into the credit_reply queue event such that
the AMQP 1.0 session process can process any credit replies
asynchronously.
Link flow control state `delivery-count` also moves to the queue processes.
The new interactions are hidden behind feature flag credit_api_v2 to
allow for rolling upgrades from 3.13 to 4.0.
9. Use serial number arithmetic in quorum queues and session process.
10. Completely bypass the rabbit_limiter module for AMQP 1.0
flow control. The goal is to eventually remove the rabbit_limiter module
in 4.0 since AMQP 0.9.1 global QoS will be unsupported in 4.0. This
commit lifts the AMQP 1.0 link flow control logic out of rabbit_limiter
into rabbit_queue_consumers.
11. Fix credit bug for streams:
AMQP 1.0 settlements shouldn't top up link credit,
only FLOW frames should top up link credit.
12. Allow sender settle mode unsettled for streams
since AMQP 1.0 acknowledgements to streams are no-ops (currently).
13. Fix AMQP 1.0 client bugs
Auto renewing credits should not be related to settling TRANSFERs.
Remove field link_credit_unsettled as it was wrong and confusing.
Prior to this commit auto renewal did not work when the sender uses
sender settlement mode settled.
14. Fix AMQP 1.0 client bugs
The wrong outdated Link was passed to function auto_flow/2
15. Use osiris chunk iterator
Only hold messages of uncompressed sub batches in memory if consumer
doesn't have sufficient credits.
Compressed sub batches are skipped for non Stream protocol consumers.
16. Fix incoming link flow control
Always use confirms between AMQP 1.0 queue clients and queue servers.
As already done internally by rabbit_fifo_client and
rabbit_stream_queue, use confirms for classic queues as well.
17. Include link handle into correlation when publishing messages to target queues
such that session process can correlate confirms from target queues to
incoming links.
18. Only grant more credits to publishers if publisher hasn't sufficient credits
anymore and there are not too many unconfirmed messages on the link.
19. Completely ignore `block` and `unblock` queue actions and RabbitMQ credit flow
between classic queue process and session process.
20. Link flow control is independent between links.
A client can refer to a queue or to an exchange with multiple
dynamically added target queues. Multiple incoming links can also fan
in to the same queue. However the link topology looks like, this
commit ensures that each link is only granted more credits if that link
isn't overloaded.
21. A connection or a session can send to many different queues.
In AMQP 0.9.1, a single slow queue will lead to the entire channel, and
then entire connection being blocked.
This commit makes sure that a single slow queue from one link won't slow
down sending on other links.
For example, having link A sending to a local classic queue and
link B sending to 5 replica quorum queue, link B will naturally
grant credits slower than link A. So, despite the quorum queue being
slower in confirming messages, the same AMQP 1.0 connection and session
can still pump data very fast into the classic queue.
22. If cluster wide memory or disk alarm occurs.
Each session sends a FLOW with incoming-window to 0 to sending client.
If sending clients don’t obey, force disconnect the client.
If cluster wide memory alarm clears:
Each session resumes with a FLOW defaulting to initial incoming-window.
23. All operations apart of publishing TRANSFERS to RabbitMQ can continue during cluster wide alarms,
specifically, attaching consumers and consuming, i.e. emptying queues.
There is no need for separate AMQP 1.0 connections for publishers and consumers as recommended in our AMQP 0.9.1 implementation.
24. Flow control summary:
* If queue becomes bottleneck, that’s solved by slowing down individual sending links (AMQP 1.0 link flow control).
* If session becomes bottleneck (more unlikely), that’s solved by AMQP 1.0 session flow control.
* If connection becomes bottleneck, it naturally won’t read fast enough from the socket causing TCP backpressure being applied.
Nowhere will RabbitMQ internal credit based flow control (i.e. module credit_flow) be used on the incoming AMQP 1.0 message path.
25. Register AMQP sessions
Prefer local-only pg over our custom pg_local implementation as
pg is a better process group implementation than pg_local.
pg_local was identified as bottleneck in tests where many MQTT clients were disconnected at once.
26. Start a local-only pg when Rabbit boots:
> A scope can be kept local-only by using a scope name that is unique cluster-wide, e.g. the node name:
> pg:start_link(node()).
Register AMQP 1.0 connections and sessions with pg.
In future we should remove pg_local and instead use the new local-only
pg for all registered processes such as AMQP 0.9.1 connections and channels.
27. Requeue messages if link detached
Although the spec allows to settle delivery IDs on detached links, RabbitMQ does not respect the 'closed'
field of the DETACH frame and therefore handles every DETACH frame as closed. Since the link is closed,
we expect every outstanding delivery to be requeued.
In addition to consumer cancellation, detaching a link therefore causes in flight deliveries to be requeued.
Note that this behaviour is different from merely consumer cancellation in AMQP 0.9.1:
"After a consumer is cancelled there will be no future deliveries dispatched to it. Note that there can
still be "in flight" deliveries dispatched previously. Cancelling a consumer will neither discard nor requeue them."
[https://www.rabbitmq.com/consumers.html#unsubscribing]
An AMQP receiver can first drain, and then detach to prevent "in flight" deliveries
28. Init AMQP session with BEGIN frame
Similar to how there can't be an MQTT processor without a CONNECT
frame, there can't be an AMQP session without a BEGIN frame.
This allows having strict dialyzer types for session flow control
fields (i.e. not allowing 'undefined').
29. Move serial_number to AMQP 1.0 common lib
such that it can be used by both AMQP 1.0 server and client
30. Fix AMQP client to do serial number arithmetic.
31. AMQP client: Differentiate between delivery-id and transfer-id for better
understandability.
32. Fix link flow control in classic queues
This commit fixes
```
java -jar target/perf-test.jar -ad false -f persistent -u cq -c 3000 -C 1000000 -y 0
```
followed by
```
./omq -x 0 amqp -T /queue/cq -D 1000000 --amqp-consumer-credits 2
```
Prior to this commit, (and on RabbitMQ 3.x) the consuming would halt after around
8 - 10,000 messages.
The bug was that in flight messages from classic queue process to
session process were not taken into account when topping up credit to
the classic queue process.
Fixes#2597
The solution to this bug (and a much cleaner design anyway independent of
this bug) is that queues should hold all link flow control state including
the delivery-count.
Hence, when credit API v2 is used the delivery-count will be held by the
classic queue process, quorum queue process, and stream queue client
instead of managing the delivery-count in the session.
33. The double level crediting between (a) session process and
rabbit_fifo_client, and (b) rabbit_fifo_client and rabbit_fifo was
removed. Therefore, instead of managing 3 separate delivery-counts (i. session,
ii. rabbit_fifo_client, iii. rabbit_fifo), only 1 delivery-count is used
in rabbit_fifo. This is a big simplification.
34. This commit fixes quorum queues without bumping the machine version
nor introducing new rabbit_fifo commands.
Whether credit API v2 is used is solely determined at link attachment time
depending on whether feature flag credit_api_v2 is enabled.
Even when that feature flag will be enabled later on, this link will
keep using credit API v1 until detached (or the node is shut down).
Eventually, after feature flag credit_api_v2 has been enabled and a
subsequent rolling upgrade, all links will use credit API v2.
This approach is safe and simple.
The 2 alternatives to move delivery-count from the session process to the
queue processes would have been:
i. Explicit feature flag credit_api_v2 migration function
* Can use a gen_server:call and only finish migration once all delivery-counts were migrated.
Cons:
* Extra new message format just for migration is required.
* Risky as migration will fail if a target queue doesn’t reply.
ii. Session always includes DeliveryCountSnd when crediting to the queue:
Cons:
* 2 delivery counts will be hold simultaneously in session proc and queue proc;
could be solved by deleting the session proc’s delivery-count for credit-reply
* What happens if the receiver doesn’t provide credit for a very long time? Is that a problem?
35. Support stream filtering in AMQP 1.0 (by @acogoluegnes)
Use the x-stream-filter-value message annotation
to carry the filter value in a published message.
Use the rabbitmq:stream-filter and rabbitmq:stream-match-unfiltered
filters when creating a receiver that wants to filter
out messages from a stream.
36. Remove credit extension from AMQP 0.9.1 client
37. Support maintenance mode closing AMQP 1.0 connections.
38. Remove AMQP 0.9.1 client dependency from AMQP 1.0 implementation.
39. Move AMQP 1.0 plugin to the core. AMQP 1.0 is enabled by default.
The old rabbitmq_amqp1_0 plugin will be kept as a no-op plugin to prevent deployment
tools from failing that execute:
```
rabbitmq-plugins enable rabbitmq_amqp1_0
rabbitmq-plugins disable rabbitmq_amqp1_0
```
40. Breaking change: Remove CLI command `rabbitmqctl list_amqp10_connections`.
Instead, list both AMQP 0.9.1 and AMQP 1.0 connections in `list_connections`:
```
rabbitmqctl list_connections protocol
Listing connections ...
protocol
{1, 0}
{0,9,1}
```
## Benchmarks
### Throughput & Latency
Setup:
* Single node Ubuntu 22.04
* Erlang 26.1.1
Start RabbitMQ:
```
make run-broker PLUGINS="rabbitmq_management rabbitmq_amqp1_0" FULL=1 RABBITMQ_SERVER_ADDITIONAL_ERL_ARGS="+S 3"
```
Predeclare durable classic queue cq1, durable quorum queue qq1, durable stream queue sq1.
Start client:
https://github.com/ssorj/quiverhttps://hub.docker.com/r/ssorj/quiver/tags (digest 453a2aceda64)
```
docker run -it --rm --add-host host.docker.internal:host-gateway ssorj/quiver:latest
bash-5.1# quiver --version
quiver 0.4.0-SNAPSHOT
```
1. Classic queue
```
quiver //host.docker.internal//amq/queue/cq1 --durable --count 1m --duration 10m --body-size 12 --credit 1000
```
This commit:
```
Count ............................................. 1,000,000 messages
Duration ............................................... 73.8 seconds
Sender rate .......................................... 13,548 messages/s
Receiver rate ........................................ 13,547 messages/s
End-to-end rate ...................................... 13,547 messages/s
Latencies by percentile:
0% ........ 0 ms 90.00% ........ 9 ms
25% ........ 2 ms 99.00% ....... 14 ms
50% ........ 4 ms 99.90% ....... 17 ms
100% ....... 26 ms 99.99% ....... 24 ms
```
RabbitMQ 3.x (main branch as of 30 January 2024):
```
---------------------- Sender ----------------------- --------------------- Receiver ---------------------- --------
Time [s] Count [m] Rate [m/s] CPU [%] RSS [M] Time [s] Count [m] Rate [m/s] CPU [%] RSS [M] Lat [ms]
----------------------------------------------------- ----------------------------------------------------- --------
2.1 130,814 65,342 6 73.6 2.1 3,217 1,607 0 8.0 511
4.1 163,580 16,367 2 74.1 4.1 3,217 0 0 8.0 0
6.1 229,114 32,767 3 74.1 6.1 3,217 0 0 8.0 0
8.1 261,880 16,367 2 74.1 8.1 67,874 32,296 8 8.2 7,662
10.1 294,646 16,367 2 74.1 10.1 67,874 0 0 8.2 0
12.1 360,180 32,734 3 74.1 12.1 67,874 0 0 8.2 0
14.1 392,946 16,367 3 74.1 14.1 68,604 365 0 8.2 12,147
16.1 458,480 32,734 3 74.1 16.1 68,604 0 0 8.2 0
18.1 491,246 16,367 2 74.1 18.1 68,604 0 0 8.2 0
20.1 556,780 32,767 4 74.1 20.1 68,604 0 0 8.2 0
22.1 589,546 16,375 2 74.1 22.1 68,604 0 0 8.2 0
receiver timed out
24.1 622,312 16,367 2 74.1 24.1 68,604 0 0 8.2 0
quiver: error: PlanoProcessError: Command 'quiver-arrow receive //host.docker.internal//amq/queue/cq1 --impl qpid-proton-c --duration 10m --count 1m --rate 0 --body-size 12 --credit 1000 --transaction-size 0 --timeout 10 --durable --output /tmp/quiver-otujr23y' returned non-zero exit status 1.
Traceback (most recent call last):
File "/usr/local/lib/quiver/python/quiver/pair.py", line 144, in run
_plano.wait(receiver, check=True)
File "/usr/local/lib/quiver/python/plano/main.py", line 1243, in wait
raise PlanoProcessError(proc)
plano.main.PlanoProcessError: Command 'quiver-arrow receive //host.docker.internal//amq/queue/cq1 --impl qpid-proton-c --duration 10m --count 1m --rate 0 --body-size 12 --credit 1000 --transaction-size 0 --timeout 10 --durable --output /tmp/quiver-otujr23y' returned non-zero exit status 1.
```
2. Quorum queue:
```
quiver //host.docker.internal//amq/queue/qq1 --durable --count 1m --duration 10m --body-size 12 --credit 1000
```
This commit:
```
Count ............................................. 1,000,000 messages
Duration .............................................. 101.4 seconds
Sender rate ........................................... 9,867 messages/s
Receiver rate ......................................... 9,868 messages/s
End-to-end rate ....................................... 9,865 messages/s
Latencies by percentile:
0% ....... 11 ms 90.00% ....... 23 ms
25% ....... 15 ms 99.00% ....... 28 ms
50% ....... 18 ms 99.90% ....... 33 ms
100% ....... 49 ms 99.99% ....... 47 ms
```
RabbitMQ 3.x:
```
---------------------- Sender ----------------------- --------------------- Receiver ---------------------- --------
Time [s] Count [m] Rate [m/s] CPU [%] RSS [M] Time [s] Count [m] Rate [m/s] CPU [%] RSS [M] Lat [ms]
----------------------------------------------------- ----------------------------------------------------- --------
2.1 130,814 65,342 9 69.9 2.1 18,430 9,206 5 7.6 1,221
4.1 163,580 16,375 5 70.2 4.1 18,867 218 0 7.6 2,168
6.1 229,114 32,767 6 70.2 6.1 18,867 0 0 7.6 0
8.1 294,648 32,734 7 70.2 8.1 18,867 0 0 7.6 0
10.1 360,182 32,734 6 70.2 10.1 18,867 0 0 7.6 0
12.1 425,716 32,767 6 70.2 12.1 18,867 0 0 7.6 0
receiver timed out
14.1 458,482 16,367 5 70.2 14.1 18,867 0 0 7.6 0
quiver: error: PlanoProcessError: Command 'quiver-arrow receive //host.docker.internal//amq/queue/qq1 --impl qpid-proton-c --duration 10m --count 1m --rate 0 --body-size 12 --credit 1000 --transaction-size 0 --timeout 10 --durable --output /tmp/quiver-b1gcup43' returned non-zero exit status 1.
Traceback (most recent call last):
File "/usr/local/lib/quiver/python/quiver/pair.py", line 144, in run
_plano.wait(receiver, check=True)
File "/usr/local/lib/quiver/python/plano/main.py", line 1243, in wait
raise PlanoProcessError(proc)
plano.main.PlanoProcessError: Command 'quiver-arrow receive //host.docker.internal//amq/queue/qq1 --impl qpid-proton-c --duration 10m --count 1m --rate 0 --body-size 12 --credit 1000 --transaction-size 0 --timeout 10 --durable --output /tmp/quiver-b1gcup43' returned non-zero exit status 1.
```
3. Stream:
```
quiver-arrow send //host.docker.internal//amq/queue/sq1 --durable --count 1m -d 10m --summary --verbose
```
This commit:
```
Count ............................................. 1,000,000 messages
Duration ................................................ 8.7 seconds
Message rate ........................................ 115,154 messages/s
```
RabbitMQ 3.x:
```
Count ............................................. 1,000,000 messages
Duration ............................................... 21.2 seconds
Message rate ......................................... 47,232 messages/s
```
### Memory usage
Start RabbitMQ:
```
ERL_MAX_PORTS=3000000 RABBITMQ_SERVER_ADDITIONAL_ERL_ARGS="+P 3000000 +S 6" make run-broker PLUGINS="rabbitmq_amqp1_0" FULL=1 RABBITMQ_CONFIG_FILE="rabbitmq.conf"
```
```
/bin/cat rabbitmq.conf
tcp_listen_options.sndbuf = 2048
tcp_listen_options.recbuf = 2048
vm_memory_high_watermark.relative = 0.95
vm_memory_high_watermark_paging_ratio = 0.95
loopback_users = none
```
Create 50k connections with 2 sessions per connection, i.e. 100k session in total:
```go
package main
import (
"context"
"log"
"time"
"github.com/Azure/go-amqp"
)
func main() {
for i := 0; i < 50000; i++ {
conn, err := amqp.Dial(context.TODO(), "amqp://nuc", &amqp.ConnOptions{SASLType: amqp.SASLTypeAnonymous()})
if err != nil {
log.Fatal("dialing AMQP server:", err)
}
_, err = conn.NewSession(context.TODO(), nil)
if err != nil {
log.Fatal("creating AMQP session:", err)
}
_, err = conn.NewSession(context.TODO(), nil)
if err != nil {
log.Fatal("creating AMQP session:", err)
}
}
log.Println("opened all connections")
time.Sleep(5 * time.Hour)
}
```
This commit:
```
erlang:memory().
[{total,4586376480},
{processes,4025898504},
{processes_used,4025871040},
{system,560477976},
{atom,1048841},
{atom_used,1042841},
{binary,233228608},
{code,21449982},
{ets,108560464}]
erlang:system_info(process_count).
450289
```
7 procs per connection + 1 proc per session.
(7 + 2*1) * 50,000 = 450,000 procs
RabbitMQ 3.x:
```
erlang:memory().
[{total,15168232704},
{processes,14044779256},
{processes_used,14044755120},
{system,1123453448},
{atom,1057033},
{atom_used,1052587},
{binary,236381264},
{code,21790238},
{ets,391423744}]
erlang:system_info(process_count).
1850309
```
7 procs per connection + 15 per session
(7 + 2*15) * 50,000 = 1,850,000 procs
50k connections + 100k session require
with this commit: 4.5 GB
in RabbitMQ 3.x: 15 GB
## Future work
1. More efficient parser and serializer
2. TODO in mc_amqp: Do not store the parsed message on disk.
3. Implement both AMQP HTTP extension and AMQP management extension to allow AMQP
clients to create RabbitMQ objects (queues, exchanges, ...).
An AMQP boolean can by encoded using 1 byte or 2 bytes:
https://docs.oasis-open.org/amqp/core/v1.0/os/amqp-core-types-v1.0-os.html#type-boolean
Prior to this commit, our Erlang parser returned:
* Erlang terms `true` or `false` for the 1 byte AMQP encoding
* Erlang terms `{boolean, true}` or `{boolean, false}` for the 2 byte AMQP enconding
Having a serializer and parser that perform the opposite actions such
that
```
Term = parse(serialize(Term))
```
is desirable as it provides a symmetric property useful not only for
property based testing, but also for avoiding altering message hashes
when serializing and parsing the same term.
However, dealing wth `{boolean, boolean()}` tuples instead of `boolean()` is very unhandy since
all Erlang code must take care of both forms leading to subtle bugs as
occurred in:
* 4cbeab8974/deps/rabbitmq_amqp1_0/src/rabbit_amqp1_0_message.erl (L155-L158)
* b8173c9d3b/deps/rabbitmq_mqtt/src/mc_mqtt.erl (L83-L88)
* b8173c9d3b/deps/rabbit/src/mc_amqpl.erl (L123-L127)
Therefore, this commits decides to take the safe approach and always
parse to an Erlang `boolean()` independent of whether the AMQP boolean
was encoded with 1 or 2 bytes.
Prior to this commit test block_connack_timeout
flaked when 2 new ports got created instead of only 1
in line
```
[NewPort] = Ports -- Ports0,
```
This commit filters for tcp_inet ports.
This will always return the port of the new MQTT connection.
* Reduce per message disk overhead
Message container annotation keys are stored on disk.
By shortening them we save 95 - 58 = 37 bytes per message.
```
1> byte_size(term_to_binary(#{exchange => <<>>, routing_keys => [<<"my-key">>], durable => true, priority => 3, timestamp => 1000})).
95
2> byte_size(term_to_binary(#{x => <<>>, rk => [<<"my-key">>], d => true, p => 3, ts => 1000})).
58
```
This should somewhat reduce disk I/O and disk space.
* Ensure durable is a boolean
Prevent key 'durable' with value 'undefined' being added to the
mc annotations, for example when the durable field was not set, but
another AMQP 1.0 header field was set.
* Apply feedback
The solution in #10203 has the following issues:
1. Bindings can be left ofter in Mnesia table rabbit_durable_queue.
One solution to 1. would be to first delete the old queue via
`rabbit_amqqueue:internal_delete(Q, User, missing_owner)`
and subsequently declare the new queue via
`rabbit_amqqueue:internal_declare(Q, false)`
However, even then, it suffers from:
2. Race conditions between `rabbit_amqqueue:on_node_down/1`
and `rabbit_mqtt_qos0_queue:declare/2`:
`rabbit_amqqueue:on_node_down/1` could first read the queue records that
need to be deleted, thereafter `rabbit_mqtt_qos0_queue:declare/2` could
re-create the queue owned by the new connection PID, and `rabbit_amqqueue:on_node_down/1`
could subsequently delete the re-created queue.
Unfortunately, `rabbit_amqqueue:on_node_down/1` does not delete
transient queues in one isolated transaction. Instead it first reads
queues and subsequenlty deletes queues in batches making it prone to
race conditions.
Ideally, this commit deletes all rabbit_mqtt_qos0_queue queues of the
node that has crashed including their bindings.
However, doing so in one transaction is risky as there may be millions
of such queues and the current code path applies the same logic on all
live nodes resulting in conflicting transactions and therefore a long
database operation.
Hence, this commit uses the simplest approach which should still be
safe:
Do not remove rabbit_mqtt_qos0_queue queues if a node crashes.
Other live nodes will continue to route to these dead queues.
That should be okay, given that the rabbit_mqtt_qos0_queue clients auto
confirm.
Continuing routing however has the effect of counting as routing result
for AMQP 0.9.1 `mandatory` property.
If an MQTT client re-connects to a live node with the same client ID,
the new node will delete and then re-create the queue.
Once the crashed node comes back online, it will clean up its leftover
queues and bindings.
When a node is shut down cleanly, the rabbit_mqtt_qos0_queue record is
removed from Mnesia.
When a node crashes and subsequently reboots the new node incarnation
removes the old rabbit_mqtt_qos0_queue record from Mnesia (via
rabbit_mqtt_qos0_queue:recover/2)
However, when a node crashes, the rabbit_mqtt_qos0_queue will be removed
from Mnesia table rabbit_queue, but will still be present in table
rabbit_durable_queue on the other live nodes.
Prior to this commit, when the same MQTT client (i.e. same MQTT client
ID) re-connects from the crashed node to another live node and
re-subscribes, the following error occurred:
```
[info] <0.43155.0> Accepted MQTT connection 10.105.0.18:60508 -> 10.105.0.10:1883 for client ID nodered_24e214feb018a232
[debug] <0.43155.0> Received a SUBSCRIBE for topic(s) [{mqtt_topic,
[debug] <0.43155.0> <<"as923/gateway/+/command/#">>,0}]
[error] <0.43155.0> Failed to declare queue 'mqtt-subscription-nodered_24e214feb018a232qos0' in vhost '/': {absent,
[error] <0.43155.0> {amqqueue,
[error] <0.43155.0> {resource,
[error] <0.43155.0> <<"/">>,
[error] <0.43155.0> queue,
[error] <0.43155.0> <<"mqtt-subscription-nodered_24e214feb018a232qos0">>},
[error] <0.43155.0> true,
[error] <0.43155.0> false,
[error] <0.43155.0> <15486.32690.0>,
[error] <0.43155.0> [],
[error] <0.43155.0> <15486.32690.0>,
[error] <0.43155.0> [],
[error] <0.43155.0> [],
[error] <0.43155.0> [],
[error] <0.43155.0> [{vhost,
[error] <0.43155.0> <<"/">>},
[error] <0.43155.0> {name,
[error] <0.43155.0> <<"ha-all-mqtt">>},
[error] <0.43155.0> {pattern,
[error] <0.43155.0> <<"^mqtt-">>},
[error] <0.43155.0> {'apply-to',
[error] <0.43155.0> <<"all">>},
[error] <0.43155.0> {definition,
[error] <0.43155.0> [{<<"ha-mode">>,
[error] <0.43155.0> <<"all">>}]},
[error] <0.43155.0> {priority,
[error] <0.43155.0> 0}],
[error] <0.43155.0> undefined,
[error] <0.43155.0> [],
[error] <0.43155.0> undefined,
[error] <0.43155.0> live,
[error] <0.43155.0> 0,
[error] <0.43155.0> [],
[error] <0.43155.0> <<"/">>,
[error] <0.43155.0> #{user =>
[error] <0.43155.0> <<"iottester">>},
[error] <0.43155.0> rabbit_mqtt_qos0_queue,
[error] <0.43155.0> #{}},
[error] <0.43155.0> nodedown}
[error] <0.43155.0> MQTT protocol error on connection 10.105.0.18:60508 -> 10.105.0.10:1883: subscribe_error
```
This commit fixes this error allowing an MQTT client that connects with CleanSession=true and
subscribes with QoS 0 to re-connect and re-subscribe to another live
node if the original Rabbit node crashes.
Reported in https://groups.google.com/g/rabbitmq-users/c/pxgy0QiwilM/m/LkJQ-3DyBgAJ
Avoid the following crash
```
** Reason for termination ==
** {mqtt_unexpected_cast,{shutdown,"Closed via management plugin"}}
crasher:
initial call: rabbit_mqtt_reader:init/1
pid: <0.1096.0>
registered_name: []
exception exit: {mqtt_unexpected_cast,
{shutdown,"Closed via management plugin"}}
in function gen_server:handle_common_reply/8 (gen_server.erl, line 1208)
```
when closing MQTT or Stream connections via HTTP API endpoint
```
/connections/username/:username
```
To refine conversion behaviour add additional tests
and ensure it matches the documentation.
mc: optionally capture source environment
And pass target environment to mc:convert
This allows environmental data and configuration to be captured and
used to modify and complete conversion logic whilst allowing conversion
code to remain pure and portable.
Previously, test pubsub was flaky
```
{shared_SUITE,pubsub,766}
{test_case_failed,missing m1}
```
because the binding wasn't present yet on node 0 when publishing to node
0.
Tests session_reconnect and session_takeover were flaky, specifically
when run under Khepri.
The issue was in the test itself that the connect properties didn't
apply. Therefore, prior to this commit an exclusive queue got created.
On `main` branch and v3.12.6 feature flag delete_ra_cluster_mqtt_node is
supported. Instead of skipping the entire test if that feature flag is
not enabled, enable the feature flag and run the test.
More generally:
"Instead of verifying if a feature flag is enabled or not, it's best to enable
it and react from the return value (success or failure).
Mixed version testing always turn off all feature flags by default.
So in the future, even though all nodes supports the mentionned
feature flag, the testcase will still be skipped." [JSP]
See commit message 00c77e0a1a for details.
In a multi node mixed version cluster where the lower version is
compiled with a different OTP version, anonymous Ra leader queries will
fail with a badfun error if initiated on the higher version and executed
on the leader on the lower version node.
This test fails when MQTT client ID tracking is performed in Ra, and the
higher version node gets compiled with a different OTP version (26) than
the lower version node (25).
The reason is described in 83eede7ef2
```
An interesting side note learned here is that the compiled file
rabbit_mqtt_collector must not be changed. This commit only modifies
function specs. However as soon as the compiled code is changed, this
module becomes a new version. The new version causes the anonymous ra query
function to fail in mixed clusters: When the old node does a
ra:leader_query where the leader is on the new node, the query function
fails on the new node with `badfun` because the new node does not have
the same module version. For more context, read:
https://web.archive.org/web/20181017104411/http://www.javalimit.com/2010/05/passing-funs-to-other-erlang-nodes.html
```
We shouldn’t use an anonymous function for ra:leader_query or ra:consistent_query.
Instead we should use the {M,F,A} form.
9e5d437a0a/src/ra.erl (L102-L103)
In MQTT the anonymous function is used in bcb95c949d/deps/rabbitmq_mqtt/src/rabbit_mqtt_collector.erl (L50)
This causes the query to return a bad fun error (silently ignored in bcb95c949d/deps/rabbitmq_mqtt/src/rabbit_mqtt_collector.erl (L70-L71) )
when executed on a different node and either:
1.) Any code in file rabbit_mqtt_collector.erl changed, or
2.) The code gets compiled with a different OTP version.
2.) is the reason for a failing mixed version test in https://github.com/rabbitmq/rabbitmq-server/pull/8553 because both higher and lower versions run OTP 26,
but the higher version node got compiled with 26 while the lower version node got compiled with 25.
The same file
compiled with OTP 26.0.1
```
1> rabbit_mqtt_collector:module_info(attributes).
[{vsn,[30045739264236496640687548892374951597]}]
```
compiled with OTP 25.3.2
```
1> rabbit_mqtt_collector:module_info(attributes).
[{vsn,[168144385419873449889532520247510637232]}]
```
Due to the very low impact that maintenance mode will not close all MQTT
client connections with feature flag delete_ra_cluster_mqtt_node being
disabled, we skip this test.
[Why]
Mnesia is a very powerful and convenient tool for Erlang applications:
it is a persistent disc-based database, it handles replication accross
multiple Erlang nodes and it is available out-of-the-box from the
Erlang/OTP distribution. RabbitMQ relies on Mnesia to manage all its
metadata:
* virtual hosts' properties
* intenal users
* queue, exchange and binding declarations (not queues data)
* runtime parameters and policies
* ...
Unfortunately Mnesia makes it difficult to handle network partition and,
as a consequence, the merge conflicts between Erlang nodes once the
network partition is resolved. RabbitMQ provides several partition
handling strategies but they are not bullet-proof. Users still hit
situations where it is a pain to repair a cluster following a network
partition.
[How]
@kjnilsson created Ra [1], a Raft consensus library that RabbitMQ
already uses successfully to implement quorum queues and streams for
instance. Those queues do not suffer from network partitions.
We created Khepri [2], a new persistent and replicated database engine
based on Ra and we want to use it in place of Mnesia in RabbitMQ to
solve the problems with network partitions.
This patch integrates Khepri as an experimental feature. When enabled,
RabbitMQ will store all its metadata in Khepri instead of Mnesia.
This change comes with behavior changes. While Khepri remains disabled,
you should see no changes to the behavior of RabbitMQ. If there are
changes, it is a bug. After Khepri is enabled, there are significant
changes of behavior that you should be aware of.
Because it is based on the Raft consensus algorithm, when there is a
network partition, only the cluster members that are in the partition
with at least `(Number of nodes in the cluster ÷ 2) + 1` number of nodes
can "make progress". In other words, only those nodes may write to the
Khepri database and read from the database and expect a consistent
result.
For instance in a cluster of 5 RabbitMQ nodes:
* If there are two partitions, one with 3 nodes, one with 2 nodes, only
the group of 3 nodes will be able to write to the database.
* If there are three partitions, two with 2 nodes, one with 1 node, none
of the group can write to the database.
Because the Khepri database will be used for all kind of metadata, it
means that RabbitMQ nodes that can't write to the database will be
unable to perform some operations. A list of operations and what to
expect is documented in the associated pull request and the RabbitMQ
website.
This requirement from Raft also affects the startup of RabbitMQ nodes in
a cluster. Indeed, at least a quorum number of nodes must be started at
once to allow nodes to become ready.
To enable Khepri, you need to enable the `khepri_db` feature flag:
rabbitmqctl enable_feature_flag khepri_db
When the `khepri_db` feature flag is enabled, the migration code
performs the following two tasks:
1. It synchronizes the Khepri cluster membership from the Mnesia
cluster. It uses `mnesia_to_khepri:sync_cluster_membership/1` from
the `khepri_mnesia_migration` application [3].
2. It copies data from relevant Mnesia tables to Khepri, doing some
conversion if necessary on the way. Again, it uses
`mnesia_to_khepri:copy_tables/4` from `khepri_mnesia_migration` to do
it.
This can be performed on a running standalone RabbitMQ node or cluster.
Data will be migrated from Mnesia to Khepri without any service
interruption. Note that during the migration, the performance may
decrease and the memory footprint may go up.
Because this feature flag is considered experimental, it is not enabled
by default even on a brand new RabbitMQ deployment.
More about the implementation details below:
In the past months, all accesses to Mnesia were isolated in a collection
of `rabbit_db*` modules. This is where the integration of Khepri mostly
takes place: we use a function called `rabbit_khepri:handle_fallback/1`
which selects the database and perform the query or the transaction.
Here is an example from `rabbit_db_vhost`:
* Up until RabbitMQ 3.12.x:
get(VHostName) when is_binary(VHostName) ->
get_in_mnesia(VHostName).
* Starting with RabbitMQ 3.13.0:
get(VHostName) when is_binary(VHostName) ->
rabbit_khepri:handle_fallback(
#{mnesia => fun() -> get_in_mnesia(VHostName) end,
khepri => fun() -> get_in_khepri(VHostName) end}).
This `rabbit_khepri:handle_fallback/1` function relies on two things:
1. the fact that the `khepri_db` feature flag is enabled, in which case
it always executes the Khepri-based variant.
4. the ability or not to read and write to Mnesia tables otherwise.
Before the feature flag is enabled, or during the migration, the
function will try to execute the Mnesia-based variant. If it succeeds,
then it returns the result. If it fails because one or more Mnesia
tables can't be used, it restarts from scratch: it means the feature
flag is being enabled and depending on the outcome, either the
Mnesia-based variant will succeed (the feature flag couldn't be enabled)
or the feature flag will be marked as enabled and it will call the
Khepri-based variant. The meat of this function really lives in the
`khepri_mnesia_migration` application [3] and
`rabbit_khepri:handle_fallback/1` is a wrapper on top of it that knows
about the feature flag.
However, some calls to the database do not depend on the existence of
Mnesia tables, such as functions where we need to learn about the
members of a cluster. For those, we can't rely on exceptions from
Mnesia. Therefore, we just look at the state of the feature flag to
determine which database to use. There are two situations though:
* Sometimes, we need the feature flag state query to block because the
function interested in it can't return a valid answer during the
migration. Here is an example:
case rabbit_khepri:is_enabled(RemoteNode) of
true -> can_join_using_khepri(RemoteNode);
false -> can_join_using_mnesia(RemoteNode)
end
* Sometimes, we need the feature flag state query to NOT block (for
instance because it would cause a deadlock). Here is an example:
case rabbit_khepri:get_feature_state() of
enabled -> members_using_khepri();
_ -> members_using_mnesia()
end
Direct accesses to Mnesia still exists. They are limited to code that is
specific to Mnesia such as classic queue mirroring or network partitions
handling strategies.
Now, to discover the Mnesia tables to migrate and how to migrate them,
we use an Erlang module attribute called
`rabbit_mnesia_tables_to_khepri_db` which indicates a list of Mnesia
tables and an associated converter module. Here is an example in the
`rabbitmq_recent_history_exchange` plugin:
-rabbit_mnesia_tables_to_khepri_db(
[{?RH_TABLE, rabbit_db_rh_exchange_m2k_converter}]).
The converter module — `rabbit_db_rh_exchange_m2k_converter` in this
example — is is fact a "sub" converter module called but
`rabbit_db_m2k_converter`. See the documentation of a `mnesia_to_khepri`
converter module to learn more about these modules.
[1] https://github.com/rabbitmq/ra
[2] https://github.com/rabbitmq/khepri
[3] https://github.com/rabbitmq/khepri_mnesia_migration
See #7206.
Co-authored-by: Jean-Sébastien Pédron <jean-sebastien@rabbitmq.com>
Co-authored-by: Diana Parra Corbacho <dparracorbac@vmware.com>
Co-authored-by: Michael Davis <mcarsondavis@gmail.com>
Fix the followin flake:
```
[ERROR] com.rabbitmq.mqtt.test.MqttTest.sessionRedelivery(TestInfo) -- Time elapsed: 0.959 s <<< FAILURE!
org.opentest4j.AssertionFailedError:
Expecting value to be false but was true
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at com.rabbitmq.mqtt.test.MqttTest.sessionRedelivery(MqttTest.java:523)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
[ERROR] Failures:
[ERROR] MqttTest.sessionRedelivery:523
Expecting value to be false but was true
```
This PR implements an approach for a "protocol (data format) agnostic core" where the format of the message isn't converted at point of reception.
Currently all non AMQP 0.9.1 originating messages are converted into a AMQP 0.9.1 flavoured basic_message record before sent to a queue. If the messages are then consumed by the originating protocol they are converted back from AMQP 0.9.1. For some protocols such as MQTT 3.1 this isn't too expensive as MQTT is mostly a fairly easily mapped subset of AMQP 0.9.1 but for others such as AMQP 1.0 the conversions are awkward and in some cases lossy even if consuming from the originating protocol.
This PR instead wraps all incoming messages in their originating form into a generic, extensible message container type (mc). The container module exposes an API to get common message details such as size and various properties (ttl, priority etc) directly from the source data type. Each protocol needs to implement the mc behaviour such that when a message originating form one protocol is consumed by another protocol we convert it to the target protocol at that point.
The message container also contains annotations, dead letter records and other meta data we need to record during the lifetime of a message. The original protocol message is never modified unless it is consumed.
This includes conversion modules to and from amqp, amqpl (AMQP 0.9.1) and mqtt.
COMMIT HISTORY:
* Refactor away from using the delivery{} record
In many places including exchange types. This should make it
easier to move towards using a message container type instead of
basic_message.
Add mc module and move direct replies outside of exchange
Lots of changes incl classic queues
Implement stream support incl amqp conversions
simplify mc state record
move mc.erl
mc dlx stuff
recent history exchange
Make tracking work
But doesn't take a protocol agnostic approach as we just convert
everything into AMQP legacy and back. Might be good enough for now.
Tracing as a whole may want a bit of a re-vamp at some point.
tidy
make quorum queue peek work by legacy conversion
dead lettering fixes
dead lettering fixes
CMQ fixes
rabbit_trace type fixes
fixes
fix
Fix classic queue props
test assertion fix
feature flag and backwards compat
Enable message_container feature flag in some SUITEs
Dialyzer fixes
fixes
fix
test fixes
Various
Manually update a gazelle generated file
until a gazelle enhancement can be made
https://github.com/rabbitmq/rules_erlang/issues/185
Add message_containers_SUITE to bazel
and regen bazel files with gazelle from rules_erlang@main
Simplify essential proprty access
Such as durable, ttl and priority by extracting them into annotations
at message container init time.
Move type
to remove dependenc on amqp10 stuff in mc.erl
mostly because I don't know how to make bazel do the right thing
add more stuff
Refine routing header stuff
wip
Cosmetics
Do not use "maybe" as type name as "maybe" is a keyword since OTP 25
which makes Erlang LS complain.
* Dedup death queue names
* Fix function clause crashes
Fix failing tests in the MQTT shared_SUITE:
A classic queue message ID can be undefined as set in
fbe79ff47b/deps/rabbit/src/rabbit_classic_queue_index_v2.erl (L1048)
Fix failing tests in the MQTT shared_SUITE-mixed:
When feature flag message_containers is disabled, the
message is not an #mc{} record, but a #basic_message{} record.
* Fix is_utf8_no_null crash
Prior to this commit, the function crashed if invalid UTF-8 was
provided, e.g.:
```
1> rabbit_misc:is_valid_shortstr(<<"😇"/utf16>>).
** exception error: no function clause matching rabbit_misc:is_utf8_no_null(<<216,61,222,7>>) (rabbit_misc.erl, line 1481)
```
* Implement mqtt mc behaviour
For now via amqp translation.
This is still work in progress, but the following SUITEs pass:
```
make -C deps/rabbitmq_mqtt ct-shared t=[mqtt,v5,cluster_size_1] FULL=1
make -C deps/rabbitmq_mqtt ct-v5 t=[mqtt,cluster_size_1] FULL=1
```
* Shorten mc file names
Module name length matters because for each persistent message the #mc{}
record is persisted to disk.
```
1> iolist_size(term_to_iovec({mc, rabbit_mc_amqp_legacy})).
30
2> iolist_size(term_to_iovec({mc, mc_amqpl})).
17
```
This commit renames the mc modules:
```
ag -l rabbit_mc_amqp_legacy | xargs sed -i 's/rabbit_mc_amqp_legacy/mc_amqpl/g'
ag -l rabbit_mc_amqp | xargs sed -i 's/rabbit_mc_amqp/mc_amqp/g'
ag -l rabbit_mqtt_mc | xargs sed -i 's/rabbit_mqtt_mc/mc_mqtt/g'
```
* mc: make deaths an annotation + fixes
* Fix mc_mqtt protocol_state callback
* Fix test will_delay_node_restart
```
make -C deps/rabbitmq_mqtt ct-v5 t=[mqtt,cluster_size_3]:will_delay_node_restart FULL=1
```
* Bazel run gazelle
* mix format rabbitmqctl.ex
* Ensure ttl annotation is refelected in amqp legacy protocol state
* Fix id access in message store
* Fix rabbit_message_interceptor_SUITE
* dializer fixes
* Fix rabbit:rabbit_message_interceptor_SUITE-mixed
set_annotation/3 should not result in duplicate keys
* Fix MQTT shared_SUITE-mixed
Up to 3.12 non-MQTT publishes were always QoS 1 regardless of delivery_mode.
75a953ce28/deps/rabbitmq_mqtt/src/rabbit_mqtt_processor.erl (L2075-L2076)
From now on, non-MQTT publishes are QoS 1 if durable.
This makes more sense.
The MQTT plugin must send a #basic_message{} to an old node that does
not understand message containers.
* Field content of 'v1_0.data' can be binary
Fix
```
bazel test //deps/rabbitmq_mqtt:shared_SUITE-mixed \
--test_env FOCUS="-group [mqtt,v4,cluster_size_1] -case trace" \
-t- --test_sharding_strategy=disabled
```
* Remove route/2 and implement route/3 for all exchange types.
This removes the route/2 callback from rabbit_exchange_type and
makes route/3 mandatory instead. This is a breaking change and
will require all implementations of exchange types to update their
code, however this is necessary anyway for them to correctly handle
the mc type.
stream filtering fixes
* Translate directly from MQTT to AMQP 0.9.1
* handle undecoded properties in mc_compat
amqpl: put clause in right order
recover death deatails from amqp data
* Replace callback init_amqp with convert_from
* Fix return value of lists:keyfind/3
* Translate directly from AMQP 0.9.1 to MQTT
* Fix MQTT payload size
MQTT payload can be a list when converted from AMQP 0.9.1 for example
First conversions tests
Plus some other conversion related fixes.
bazel
bazel
translate amqp 1.0 null to undefined
mc: property/2 and correlation_id/message_id return type tagged values.
To ensure we can support a variety of types better.
The type type tags are AMQP 1.0 flavoured.
fix death recovery
mc_mqtt: impl new api
Add callbacks to allow protocols to compact data before storage
And make readable if needing to query things repeatedly.
bazel fix
* more decoding
* tracking mixed versions compat
* mc: flip default of `durable` annotation to save some data.
Assuming most messages are durable and that in memory messages suffer less
from persistence overhead it makes sense for a non existent `durable`
annotation to mean durable=true.
* mc conversion tests and tidy up
* mc make x_header unstrict again
* amqpl: death record fixes
* bazel
* amqp -> amqpl conversion test
* Fix crash in mc_amqp:size/1
Body can be a single amqp-value section (instead of
being a list) as shown by test
```
make -C deps/rabbitmq_amqp1_0/ ct-system t=java
```
on branch native-amqp.
* Fix crash in lists:flatten/1
Data can be a single amqp-value section (instead of
being a list) as shown by test
```
make -C deps/rabbitmq_amqp1_0 ct-system t=dotnet:roundtrip_to_amqp_091
```
on branch native-amqp.
* Fix crash in rabbit_writer
Running test
```
make -C deps/rabbitmq_amqp1_0 ct-system t=dotnet:roundtrip_to_amqp_091
```
on branch native-amqp resulted in the following crash:
```
crasher:
initial call: rabbit_writer:enter_mainloop/2
pid: <0.711.0>
registered_name: []
exception error: bad argument
in function size/1
called as size([<<0>>,<<"Sw">>,[<<160,2>>,<<"hi">>]])
*** argument 1: not tuple or binary
in call from rabbit_binary_generator:build_content_frames/7 (rabbit_binary_generator.erl, line 89)
in call from rabbit_binary_generator:build_simple_content_frames/4 (rabbit_binary_generator.erl, line 61)
in call from rabbit_writer:assemble_frames/5 (rabbit_writer.erl, line 334)
in call from rabbit_writer:internal_send_command_async/3 (rabbit_writer.erl, line 365)
in call from rabbit_writer:handle_message/2 (rabbit_writer.erl, line 265)
in call from rabbit_writer:handle_message/3 (rabbit_writer.erl, line 232)
in call from rabbit_writer:mainloop1/2 (rabbit_writer.erl, line 223)
```
because #content.payload_fragments_rev is currently supposed to
be a flat list of binaries instead of being an iolist.
This commit fixes this crash inefficiently by calling
iolist_to_binary/1. A better solution would be to allow AMQP legacy's #content.payload_fragments_rev
to be an iolist.
* Add accidentally deleted line back
* mc: optimise mc_amqp internal format
By removint the outer records for message and delivery annotations
as well as application properties and footers.
* mc: optimis mc_amqp map_add by using upsert
* mc: refactoring and bug fixes
* mc_SUITE routingheader assertions
* mc remove serialize/1 callback as only used by amqp
* mc_amqp: avoid returning a nested list from protocol_state
* test and bug fix
* move infer_type to mc_util
* mc fixes and additiona assertions
* Support headers exchange routing for MQTT messages
When a headers exchange is bound to the MQTT topic exchange, routing
will be performend based on both MQTT topic (by the topic exchange) and
MQTT User Property (by the headers exchange).
This combines the best worlds of both MQTT 5.0 and AMQP 0.9.1 and
enables powerful routing topologies.
When the User Property contains the same name multiple times, only the
last name (and value) will be considered by the headers exchange.
* Fix crash when sending from stream to amqpl
When publishing a message via the stream protocol and consuming it via
AMQP 0.9.1, the following crash occurred prior to this commit:
```
crasher:
initial call: rabbit_channel:init/1
pid: <0.818.0>
registered_name: []
exception exit: {{badmatch,undefined},
[{rabbit_channel,handle_deliver0,4,
[{file,"rabbit_channel.erl"},
{line,2728}]},
{lists,foldl,3,[{file,"lists.erl"},{line,1594}]},
{rabbit_channel,handle_cast,2,
[{file,"rabbit_channel.erl"},
{line,728}]},
{gen_server2,handle_msg,2,
[{file,"gen_server2.erl"},{line,1056}]},
{proc_lib,wake_up,3,
[{file,"proc_lib.erl"},{line,251}]}]}
```
This commit first gives `mc:init/3` the chance to set exchange and
routing_keys annotations.
If not set, `rabbit_stream_queue` will set these annotations assuming
the message was originally published via the stream protocol.
* Support consistent hash exchange routing for MQTT 5.0
When a consistent hash exchange is bound to the MQTT topic exchange,
MQTT 5.0 messages can be routed to queues consistently based on the
Correlation-Data in the PUBLISH packet.
* Convert MQTT 5.0 User Property
* to AMQP 0.9.1 headers
* from AMQP 0.9.1 headers
* to AMQP 1.0 application properties and message annotations
* from AMQP 1.0 application properties and message annotations
* Make use of Annotations in mc_mqtt:protocol_state/2
mc_mqtt:protocol_state/2 includes Annotations as parameter.
It's cleaner to make use of these Annotations when computing the
protocol state instead of relying on the caller (rabbitmq_mqtt_processor)
to compute the protocol state.
* Enforce AMQP 0.9.1 field name length limit
The AMQP 0.9.1 spec prohibits field names longer than 128 characters.
Therefore, when converting AMQP 1.0 message annotations, application
properties or MQTT 5.0 User Property to AMQP 0.9.1 headers, drop any
names longer than 128 characters.
* Fix type specs
Apply feedback from Michael Davis
Co-authored-by: Michael Davis <mcarsondavis@gmail.com>
* Add mc_mqtt unit test suite
Implement mc_mqtt:x_header/2
* Translate indicator that payload is UTF-8 encoded
when converting between MQTT 5.0 and AMQP 1.0
* Translate single amqp-value section from AMQP 1.0 to MQTT
Convert to a text representation, if possible, and indicate to MQTT
client that the payload is UTF-8 encoded. This way, the MQTT client will
be able to parse the payload.
If conversion to text representation is not possible, encode the payload
using the AMQP 1.0 type system and indiate the encoding via Content-Type
message/vnd.rabbitmq.amqp.
This Content-Type is not registered.
Type "message" makes sense since it's a message.
Vendor tree "vnd.rabbitmq.amqp" makes sense since merely subtype "amqp" is not
registered.
* Fix payload conversion
* Translate Response Topic between MQTT and AMQP
Translate MQTT 5.0 Response Topic to AMQP 1.0 reply-to address and vice
versa.
The Response Topic must be a UTF-8 encoded string.
This commit re-uses the already defined RabbitMQ target addresses:
```
"/topic/" RK Publish to amq.topic with routing key RK
"/exchange/" X "/" RK Publish to exchange X with routing key RK
```
By default, the MQTT topic exchange is configure dto be amq.topic using
the 1st target address.
When an operator modifies the mqtt.exchange, the 2nd target address is
used.
* Apply PR feedback
and fix formatting
Co-authored-by: Michael Davis <mcarsondavis@gmail.com>
* tidy up
* Add MQTT message_containers test
* consistent hash exchange: avoid amqp legacy conversion
When hashing on a header value.
* Avoid converting to amqp legacy when using exchange federation
* Fix test flake
* test and dialyzer fixes
* dialyzer fix
* Add MQTT protocol interoperability tests
Test receiving from and sending to MQTT 5.0 and
* AMQP 0.9.1
* AMQP 1.0
* STOMP
* Streams
* Regenerate portions of deps/rabbit/app.bzl with gazelle
I'm not exactly sure how this happened, but gazell seems to have been
run with an older version of the rules_erlang gazelle extension at
some point. This caused generation of a structure that is no longer
used. This commit updates the structure to the current pattern.
* mc: refactoring
* mc_amqpl: handle delivery annotations
Just in case they are included.
Also use iolist_to_iovec to create flat list of binaries when
converting from amqp with amqp encoded payload.
---------
Co-authored-by: David Ansari <david.ansari@gmx.de>
Co-authored-by: Michael Davis <mcarsondavis@gmail.com>
Co-authored-by: Rin Kuryloski <kuryloskip@vmware.com>
Why:
A RabbitMQ operator should be able to see whether RabbitMQ drops MQTT
QoS 0 messages due to overload protection. It's an indication that an
MQTT subscriber does not consume fast enough.
How:
Use Prometheus global counters.
There are 2 valid solutions:
1. Introduce a new metric called messages_dropped specifically for the
rabbitmq_mqtt_qos0_queue type. This would work in a similar fashion
how streams extends the per protocol global counters, but requires
extending the per protocol & queue type global counters for the MQTT
QoS queue type. The emitted metrics would look as follows:
```
rabbitmq_global_messages_dropped_total{protocol="mqtt310",queue_type="rabbit_mqtt_qos0_queue"} 0
rabbitmq_global_messages_dropped_total{protocol="mqtt311",queue_type="rabbit_mqtt_qos0_queue"} 0
rabbitmq_global_messages_dropped_total{protocol="mqtt50",queue_type="rabbit_mqtt_qos0_queue"} 0
```
2. Reuse the existing metric rabbitmq_global_messages_dead_lettered_maxlen_total
This commit decides to go for the 2nd approach because:
a) there is no need to add a new metric. Even though dead lettering is not supported
for the MQTT QoS 0 queue type, this metric maps nicely to
what happens: The queue drop messages since itx max length
(mqtt.mailbox_soft_limit) is exceeded with overflow behaviour
drop-head. Furtheremore the label `dead_letter_strategy="disabled"` tells
that dead lettering is not taking place from this queue type.
b) this metric allows to support dead lettering for the MQTT QoS 0 queue
type in the future.
The new dead lettering metrics look as follows:
```
rabbitmq_global_messages_dead_lettered_maxlen_total{queue_type="rabbit_classic_queue",dead_letter_strategy="at_most_once"} 0
rabbitmq_global_messages_dead_lettered_maxlen_total{queue_type="rabbit_classic_queue",dead_letter_strategy="disabled"} 0
rabbitmq_global_messages_dead_lettered_maxlen_total{queue_type="rabbit_mqtt_qos0_queue",dead_letter_strategy="disabled"} 0
rabbitmq_global_messages_dead_lettered_maxlen_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="at_most_once"} 0
rabbitmq_global_messages_dead_lettered_maxlen_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="disabled"} 0
rabbitmq_global_messages_dead_lettered_expired_total{queue_type="rabbit_classic_queue",dead_letter_strategy="at_most_once"} 0
rabbitmq_global_messages_dead_lettered_expired_total{queue_type="rabbit_classic_queue",dead_letter_strategy="disabled"} 0
rabbitmq_global_messages_dead_lettered_expired_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="at_least_once"} 0
rabbitmq_global_messages_dead_lettered_expired_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="at_most_once"} 0
rabbitmq_global_messages_dead_lettered_expired_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="disabled"} 0
rabbitmq_global_messages_dead_lettered_rejected_total{queue_type="rabbit_classic_queue",dead_letter_strategy="at_most_once"} 0
rabbitmq_global_messages_dead_lettered_rejected_total{queue_type="rabbit_classic_queue",dead_letter_strategy="disabled"} 0
rabbitmq_global_messages_dead_lettered_rejected_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="at_least_once"} 0
rabbitmq_global_messages_dead_lettered_rejected_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="at_most_once"} 0
rabbitmq_global_messages_dead_lettered_rejected_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="disabled"} 0
rabbitmq_global_messages_dead_lettered_delivery_limit_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="at_least_once"} 0
rabbitmq_global_messages_dead_lettered_delivery_limit_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="at_most_once"} 0
rabbitmq_global_messages_dead_lettered_delivery_limit_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="disabled"} 0
rabbitmq_global_messages_dead_lettered_confirmed_total{queue_type="rabbit_quorum_queue",dead_letter_strategy="at_least_once"} 0
```
Multiple things were wrong in this test:
1. The test name ssl_user_port_vhost_mapping_takes_precedence_over_cert_vhost_mapping was wrong.
As written in our docs, the opposite is true
> The certificate-to-vhost mapping with the mqtt_default_vhosts global parameter is considered more specific than the port-to-vhost mapping with the mqtt_port_to_vhost_mapping global parameter and so takes precedence over it.
2. The test case didn't test what it was supposed to test:
The test relies on revoking the permissions that were set for the
port_to_vhost mapping. However revoking these permission did not happen
because:
2.a) The wrong Config was used, and
2.b) The wrong key was used.
2. could be observed by the following CT warning being logged:
```
Could not find element mqtt_port_to_vhost_mapping in Config.
```
since MQTT 5.0 supports negative acknowledgements thanks to reason codes
in the PUBACK packet.
We could either choose reason code 128 or 131. The description code for
131 applies for rejected messages, hence this commit uses 131:
> The PUBLISH is valid but the receiver is not willing to accept it.
due to AMQP 1.0 spec:
> The annotations type is a map where the keys are restricted to be of type symbol or of type ulong.
All ulong keys, and all symbolic keys except those beginning with "x-" are reserved.
Keys beginning with "x-opt-" MUST be ignored if not understood.
On receiving an annotation key which is not understood, and which does not begin with "x-opt",
the receiving AMQP container MUST detach the link with a not-implemented error.
So, for new headers being introduced it makes sense to comply with that
AMQP 1.0 requirement. We don't want the receiver to force to understand
this header.
Starting with RabbitMQ 3.13 mqtt.max_session_expiry_interval_seconds
(set in seconds) will replace the previous setting
mqtt.subscription_ttl.
MQTT 5.0 introduces the Session Expiry Interval
feature which does not only apply to subscribers, but also to
publishers.
The new config name mqtt.max_session_expiry_interval_seconds makes it clear
that it also applies to publishers.
Prior to this commit, when mqtt.subscription_ttl was set, a warning got
logged and the value was ignored. This is dangerous if an operator does
not see the warning but relies for example on `mqtt.subscription =
infinity` to not expire non clean session.
It's safer to make the boot fail if that unsupported config name is
still set. A clear error message will be logged:
```
[error] <0.142.0> Error preparing configuration in phase apply_translations:
[error] <0.142.0> - Translation for 'rabbitmq_mqtt.subscription_ttl' found invalid configuration:
Since 3.13 mqtt.subscription_ttl (in milliseconds) is unsupported.
Use mqtt.max_session_expiry_interval_seconds (in seconds) instead.
```
Alternatively, RabbitMQ could translate mqtt.subscription_ttl to
mqtt.max_session_expiry_interval_seconds.
However, forcing the new config option sounds the better way to go.
Once we write MQTT 5.0 docs, this change must go into the 3.13 release notes.
This commit also renames max_session_expiry_interval_secs to max_session_expiry_interval_seconds.
The latter is clearer to users.
and CLI as requested in
https://github.com/rabbitmq/rabbitmq-server/issues/2554#issuecomment-1604205277
"User Properties on the CONNECT packet can be used to send connection related properties from the Client to the Server.
The meaning of these properties is not defined by this specification."
[v5 3.1.2.11.8]
It makes sense to display the User Property of the CONNECT packet in the
Management UI in the connection's Client Properties.
Test
```
//deps/rabbitmq_mqtt:shared_SUITE-mixed --test_env FOCUS="-group [web_mqtt,v3,cluster_size_1] -case block_only_publisher"
```
was flaky:
```
=== Ended at 2023-06-26 07:09:57
=== Location: [{shared_SUITE,block_only_publisher,1323},
{test_server,ts_tc,1782},
{test_server,run_test_case_eval1,1291},
{test_server,run_test_case_eval,1223}]
=== === Reason: no match of right hand side value {error,ack_timeout}
in function shared_SUITE:block_only_publisher/1 (shared_SUITE.erl, line 1323)
in call from test_server:ts_tc/3 (test_server.erl, line 1782)
in call from test_server:run_test_case_eval1/6 (test_server.erl, line 1291)
in call from test_server:run_test_case_eval/9 (test_server.erl, line 1223)
```
It seems that the ack_timeout of 1 second was too low for a
subscription.
Attempt to fix the following flake:
```
=== Ended at 2023-06-26 07:13:34
=== Location: [{shared_SUITE,events,570},
{test_server,ts_tc,1782},
{test_server,run_test_case_eval1,1291},
{test_server,run_test_case_eval,1223}]
=== === Reason: no match of right hand side value []
in function shared_SUITE:events/1 (shared_SUITE.erl, line 570)
in call from test_server:ts_tc/3 (test_server.erl, line 1782)
in call from test_server:run_test_case_eval1/6 (test_server.erl, line 1291)
in call from test_server:run_test_case_eval/9 (test_server.erl, line 1223)
```
of test
```
-group [web_mqtt,v3,cluster_size_1] -case events
```
The logs showed that deletion of the exclusive queue took place in the
same millisecond as the server received the DISCONNECT:
```
2023-06-26 07:13:32.838282+00:00 [debug] <0.2494.0> Received a CONNECT, client ID: events, username: undefined, clean start: true, protocol version: 3, keepalive: 60, property names: []
2023-06-26 07:13:32.838436+00:00 [debug] <0.2494.0> MQTT connection 127.0.0.1:38808 -> 127.0.0.1:21007 picked vhost using plugin_configuration_or_default_vhost
2023-06-26 07:13:32.838523+00:00 [debug] <0.2494.0> User 'guest' authenticated successfully by backend rabbit_auth_backend_internal
2023-06-26 07:13:32.838672+00:00 [info] <0.2494.0> Accepted Web MQTT connection 127.0.0.1:38808 -> 127.0.0.1:21007 for client ID events
2023-06-26 07:13:33.147196+00:00 [debug] <0.2494.0> Received a SUBSCRIBE with subscription(s) [{mqtt_subscription,<<"my/topic">>,
2023-06-26 07:13:33.147196+00:00 [debug] <0.2494.0> {mqtt_subscription_opts,0,false,
2023-06-26 07:13:33.147196+00:00 [debug] <0.2494.0> false,0,undefined}}]
2023-06-26 07:13:33.457541+00:00 [debug] <0.2494.0> Received an UNSUBSCRIBE for topic filter(s) [<<"my/topic">>]
2023-06-26 07:13:33.762171+00:00 [debug] <0.2494.0> Received a DISCONNECT with reason code 0 and properties #{}
2023-06-26 07:13:33.762350+00:00 [info] <0.2494.0> Web MQTT closing connection 127.0.0.1:38808 -> 127.0.0.1:21007
2023-06-26 07:13:33.762780+00:00 [debug] <0.2504.0> Deleting exclusive queue 'mqtt-subscription-eventsqos0' in vhost '/' because its declaring connection <0.2494.0> was closed
```
However, there could be some delay between disconnecting on the client
WebMQTT side and the processor processing the DISCONNECT packet.
due to the following flake:
```
v5_SUITE:subscription_identifier failed on line 783
Reason: {test_case_failed,Received unexpected message: {publish,#{client_pid => <0.495.0>,dup => false,
packet_id => undefined,
payload => <<"m3">>,properties => #{},
qos => 0,retain => true,
topic => <<"t/3">>,
via => #Port<0.164>}}}
```
Also, log if unexpected message received due to flake in
```
=== Ended at 2023-06-22 14:30:07
=== Location: [{v5_SUITE,will_delay_message_expiry_publish_properties,1597},
{test_server,ts_tc,1782},
{test_server,run_test_case_eval1,1291},
{test_server,run_test_case_eval,1223}]
=== === Reason: {test_case_failed,"did not receive Will Message"}
```
- testQueuePropertiesWithCleanSessionSet() was not used
- testQueuePropertiesWithCleanSessionUnset() and
testQueuePropertiesWithCleanSession() was called only once so removing
the extra layer here to simply structure
- no need to set username and password unless they are different from
guest/guest
- clean start and clean session default to true; no need to set
explicitly
- same tests as v3 test suite, with pathos mqtt V5 client.
- two test cases are removed:
1. sessionRedelivery callback behaviors in v3 and v5 client seems
to be different that throwing exception does not shutdown a v5 client
immediately. This test case tests that unacked qos1 msgs are redelivered
by RMQ broker, which is covered in other test suite
2. lastWillDowngradesQoS2 is removed because for mqtt 5, will msgs with
unsupported Qos is an error and not accepted
This commit fixes the following crash:
```
2388-2023-06-21 08:53:28.189519+00:00 [error] <0.2191.0> exception error: bad argument
2389-2023-06-21 08:53:28.189519+00:00 [error] <0.2191.0> in function lists:keymember/3
2390-2023-06-21 08:53:28.189519+00:00 [error] <0.2191.0> called as lists:keymember(<<"x-mqtt-publish-qos">>,1,undefined)
2391-2023-06-21 08:53:28.189519+00:00 [error] <0.2191.0> *** argument 3: not a list
2392-2023-06-21 08:53:28.189519+00:00 [error] <0.2191.0> in call from rabbit_mqtt_processor:amqp_props_to_mqtt_props/2 (rabbit_mqtt_processor.erl, line 2219)
```
This crash occurs when a message without AMQP 0.9.1 #P_basic.headers
is sent to the MQTT v4 connection process, but consumed by an MQTT v5
connection process.
This is the case when an AMQP 0.9.1 client sends a message to a v4 MQTT
client, and this same client subsequently upgrades to v5 consuming the
message.
When sending from AMQP 0.9.1 client directly to a v5 MQTT connection,
the AMQP 0.9.1 header <<"x-binding-keys">> is set.
When sending from AMQP 0.9.1 client directly to a v4 MQTT connection,
no header is set, but this code branch was not evaluated.
RabbitMQ MQTT already supports authenticating clients via
username + password, OAuth tokens, and certificates.
We could make use of RabbitMQ SASL mechanisms in the future,
if needed. For now, if the client wants to perform extended
authentication, we return Bad Authentication Method in the CONNACK
packet.
Once the server's Topic Alias cache for messages from server to client
is full, this commit does not replace any existing aliases.
So, the first topics "win" and stay in the cache forever.
This matches the behaviour of VerneMQ and EMQX.
For now that's good enough.
In the future, we can easily change that behaviour to some smarter strategy,
for example
1. Hash the TopicName to an Topic Alias and replace the old
alias, or
2. For the Topic Alias Cache from server to client, keep 2 Maps:
#{TopicName => TopicAlias} and #{TopicAlias => TopicName} and a
counter that wraps to 1 once the Topic Alias Maximum is reached and
just replace an existing Alias if the TopicName is not cached.
Also, refactor Topic Alias Maximum:
* Remove code duplication
* Allow an operator to prohibit Topic Aliases by allowing value 0 to be
configured
* Change config name to topic_alias_maximum to that it matches exactly
the MQTT feture name
* Fix wrong code formatting
* Add the invalid or unkown Topic Alias to log message for easier
troubleshooting
For MQTT 5.0 destination queues, the topic exchange does not only have
to return the destination queue names, but also the matched binding
keys.
This is needed to implement MQTT 5.0 subscription options No Local,
Retain As Published and Subscription Identifiers.
Prior to this commit, as the trie was walked down, we remembered the
edges being walked and assembled the final binding key with
list_to_binary/1.
list_to_binary/1 is very expensive with long lists (long topic names),
even in OTP 26.
The CPU flame graph showed ~3% of CPU usage was spent only in
list_to_binary/1.
Unfortunately and unnecessarily, the current topic exchange
implementation stores topic levels as lists.
It would be better to store topic levels as binaries:
split_topic_key/1 should ideally use binary:split/3 similar as follows:
```
1> P = binary:compile_pattern(<<".">>).
{bm,#Ref<0.1273071188.1488322568.63736>}
2> Bin = <<"aaa.bbb..ccc">>.
<<"aaa.bbb..ccc">>
3> binary:split(Bin, P, [global]).
[<<"aaa">>,<<"bbb">>,<<>>,<<"ccc">>]
```
The compiled pattern could be placed into persistent term.
This commit decided to avoid migrating Mnesia tables to use binaries
instead of lists. Mnesia migrations are non-trivial, especially with the
current feature flag subsystem.
Furthermore the Mnesia topic tables are already getting migrated to
their Khepri counterparts in 3.13.
Adding additional migration only for Mnesia does not make sense.
So, instead of assembling the binding key as we walk down the trie and
then calling list_to_binary/1 in the leaf, it
would be better to just fetch the binding key from the database in the leaf.
As we reach the leaf of the trie, we know both source and destination.
Unfortunately, we cannot fetch the binding key efficiently with the
current rabbit_route (sorted by source exchange) and
rabbit_reverse_route (sorted by destination) tables as the key is in
the middle between source and destination.
If there are a huge number of bindings for a given sourc exchange (very
realistic in MQTT use cases) or a large number of bindings for a given
destination (also realistic), it would require scanning these large
number of bindings.
Therefore this commit takes the simplest possible solution:
The solution leverages the fact that binding arguments are already part of
table rabbit_topic_trie_binding.
So, if we simply include the binding key into the binding arguments, we
can fetch and return it efficiently in the topic exchange
implementation.
The following patch omitting fetching the empty list binding argument
(the default) makes routing slower because function
`analyze_pattern.constprop.0` requires significantly more (~2.5%) CPU time
```
@@ -273,7 +273,11 @@ trie_bindings(X, Node) ->
node_id = Node,
destination = '$1',
arguments = '$2'}},
- mnesia:select(?MNESIA_BINDING_TABLE, [{MatchHead, [], [{{'$1', '$2'}}]}]).
+ mnesia:select(
+ ?MNESIA_BINDING_TABLE,
+ [{MatchHead, [{'andalso', {'is_list', '$2'}, {'=/=', '$2', []}}], [{{'$1', '$2'}}]},
+ {MatchHead, [], ['$1']}
+ ]).
```
Hence, this commit always fetches the binding arguments.
All MQTT 5.0 destination queues will create a binding that
contains the binding key in the binding arguments.
Not only does this solution avoid expensive list_to_binay/1 calls, but
it also means that Erlang app rabbit (specifically the topic exchange
implementation) does not need to be aware of MQTT anymore:
It just returns the binding key when the binding args tell to do so.
In future, once the Khepri migration completed, we should be able to
relatively simply remove the binding key from the binding arguments
again to free up some storage space.
Note that one of the advantages of a trie data structue is its space
efficiency that you don't have to store the same prefixes multiple
times.
However, for RabbitMQ the binding key is already stored at least N times
in various routing tables, so storing it a few times more via the
binding arguments should be acceptable.
The speed improvements are favoured over a few more MBs ETS usage.
The format of #mqtt_msg{} changes from 3.12 to 3.13.
In 3.13 the record contains 2 additional fields:
* props
* timestamp
The old #mqtt_msg{} might still be stored by the retained message store
in ets or dets.
This commit converts such an old message format when read from the
database.
The alternative would have been to run a migration function over the
whole table which is slightly more complex to implement.
Instead of giving the new message format a different record name,
e.g. #mqtt_msg_v2{}, this commit decides to re-use the same name such
that the new code only handles the record name #mqtt_msg{}.
When RabbitMQ enters maintenance mode / is being drained, all client
connections are closed.
This commit sends a DISCONNECT packet to (Web) MQTT 5.0 clients with
Reason Code "Server shutting down" before the connection is closed.
The following PUBLISH and Will properties are forwarded unaltered by the
server:
* Payload Format Indicator
* Content Type
* Response Topic
* Correlation Data
* User Property
Not only must these properties be forwarded unaltered from an MQTT
publishing client to an MQTT receiving client, but it would also be nice
to allow for protocol interoperability:
Think about RPC request-response style patterns where the requester is
an MQTT client and the responder is an AMQP 0.9.1 or STOMP client.
We reuse the P_basic fields where possible:
* content_type (if <= 255 bytes)
* correlation_id (if <= 255 bytes)
Otherwise, we add custom AMQP 0.9.1 headers.
The headers follow the naming pattern "x-mqtt-<property>" where
<property> is the MQTT v5 property if that property makes only
(mainly) sense in the MQTT world:
* x-mqtt-user-property
* x-mqtt-payload-format-indicator
If the MQTT v5 property makes also sense outside of the MQTT world, we
name it more generic:
* x-correlation (if > 255 bytes)
* x-reply-to-topic (since P_basic.reply_to assumes a queue name)
In the future, we can think about adding a header x-reply-to-exchange
and have the MQTT plugin set its value to the configured mqtt.exchange
such that clients don't have to assume the default topic exchange amq.topic.
Previously, the Will Message could be kept in memory in the MQTT
connection process state. Upon termination, the Will Message is sent.
The new MQTT 5.0 feature Will Delay Interval requires storing the Will
Message outside of the MQTT connection process state.
The Will Message should not be stored node local because the client
could reconnect to a different node.
Storing the Will Message in Mnesia is not an option because we want to
get rid of Mnesia. Storing the Will Message in a Ra cluster or in Khepri
is only an option if the Will Payload is small as there is currently no
way in Ra to **efficiently** snapshot large binary data (Note that these
Will Messages are not consumed in a FIFO style workload like messages in
quorum queues. A Will Message needs to be stored for as long as the
Session lasts - up to 1 day by default, but could also be much longer if
RabbitMQ is configured with a higher maximum session expiry interval.)
Usually Will Payloads are small: They are just a notification that its
MQTT session ended abnormally. However, we don't know how users leverage
the Will Message feature. The MQTT protocol allows for large Will Payloads.
Therefore, the solution implemented in this commit - which should work
good enough - is storing the Will Message in a queue.
Each MQTT session which has a Session Expiry Interval and Will Delay
Interval of > 0 seconds will create a queue if the current Network
Connection ends where it stores its Will Message. The Will Message has a
message TTL set (corresponds to the Will Delay Interval) and the queue
has a queue TTL set (corresponds to the Session Expiry Interval).
If the client does not reconnect within the Will Delay Interval, the
message is dead lettered to the configured MQTT topic exchange
(amq.topic by default).
The Will Delay Interval can be set by both publishers and subscribers.
Therefore, the Will Message is the 1st session state that RabbitMQ keeps
for publish-only MQTT clients.
One current limitation of this commit is that a Will Message that is
delayed (i.e. Will Delay Interval is set) and retained (i.e. Will Retain
flag set) will not be retained.
One solution to retain delayed Will Messages is that the retainer
process consumes from a queue and the queue binds to the topic exchange
with a topic starting with `$`, for example `$retain/#`.
The AMQP 0.9.1 Will Message that is dead lettered could then be added a
CC header such that it won't not only be published with the Will Topic,
but also with `$retain` topic. For example, if the Will Topic is `a/b`,
it will publish with routing key `a/b` and CC header `$retain/a/b`.
The reason this is not implemented in this commit is that to keep the
currently broken retained message store behaviour, we would require
creating at least one queue per node and publishing only to that local
queue. In future, once we have a replicated retained message store based
on a Stream for example, we could just publish all retained messages to
the `$retain` topic and thefore into the Stream.
So, for now, we list "retained and delayed Will Messages" as a limitation
that they actually won't be retained.
This commit fixes 2 separate issues:
1. No quorum queue got created in v5 because Session Expiry Interval was 0.
2. Fix a function_clause error. Pass the decoded properties further to other
functions looking up headers.
due to rebasing onto main.
mqtt5 branch adds a new header
```
{<<"x-mqtt-retain">>, bool, false}
```
which caused the incoming_message_interceptors test case to fail.
The MQTT v5 spec is a bit vague on Retain Handling 1:
"If Retain Handling is set to 1 then if the subscription did not
already exist, the Server MUST send all retained message matching the
Topic Filter of the subscription to the Client, and if the subscription
did exist the Server MUST NOT send the retained messages.
[MQTT-3.3.1-10]." [v5 3.3.1.3]
Does a subscription with the same topic filter but different
subscription options mean that "the subscription did exist"?
This commit interprets "subscription exists" as both topic filter and
subscription options must be the same.
Therefore, if a client creates a subscription with a topic filter that
is identical to a previous subscription and subscription options that
are different and Retain Handling 1, the server sends the retained
message.
Support subscription options "No Local" and "Retain As Published"
as well as Subscription Identifiers.
All three MQTT 5.0 features can be set on a per subscription basis.
Due to wildcards in topic filters, multiple subscriptions
can match a given topic. Therefore, to implement Retain As Published and
Subscription Identifiers, the destination MQTT connection process needs
to know what subscription(s) caused it to receive the message.
There are a few ways how this could be implemented:
1. The destination MQTT connection process is aware of all its
subscriptions. Whenever, it receives a message, it can match the
message's routing key / topic against all its known topic filters.
However, to iteratively match the routing key against all topic
filters for every received message can become very expensive in the
worst case when the MQTT client creates many subscriptions containing
wildcards. This could be the case for an MQTT client that acts as a
bridge or proxy or dispatcher: It could subscribe via a wildcard for
each of its own clients.
2. Instead of interatively matching the topic of the received message
against all topic filters that contain wildcards, a better approach
would be for every MQTT subscriber connection process to maintain a
local trie datastructure (similar to how topic exchanges are
implemented) and perform matching therefore more efficiently.
However, this does not sound optimal either because routing is
effectively performed twice: in the topic exchange and again against
a much smaller trie in each destination connection process.
3. Given that the topic exchange already perform routing, a much more
sensible way would be to send the matched binding key(s) to the
destination MQTT connection process. A subscription (topic filter)
maps to a binding key in AMQP 0.9.1 routing. Therefore, for the first
time in RabbitMQ, the routing function should not only output a list
of unique destination queues, but also the binding keys (subscriptions)
that caused the message to be routed to the destination queue.
This commit therefore implements the 3rd approach.
The downside of the 3rd approach is that it requires API changes to the
routing function and topic exchange.
Specifically, this commit adds a new function rabbit_exchange:route/3
that accepts a list of routing options. If that list contains version 2,
the caller of the routing function knows how to handle the return value
that could also contain binding keys.
This commits allows an MQTT connection process, the channel process, and
at-most-once dead lettering to handle binding keys. Binding keys are
included as AMQP 0.9.1 headers into the basic message.
Therefore, whenever a message is sent from an MQTT client or AMQP 0.9.1
client or AMQP 1.0 client or STOMP client, the MQTT receiver will know
the subscription identifier that caused the message to be received.
Note that due to the low number of allowed wildcard characters (# and
+), the cardinality of matched binding keys shouldn't be high even if
the topic contains for example 3 levels and the message is sent to for
example 5 million destination queues. In other words, sending multiple
distinct basic messages to the destination shouldn't hurt the delegate
optimisation too much. The delegate optimisation implemented for classic
queues and rabbit_mqtt_qos0_queue(s) still takes place for all basic
messages that contain the same set of matched binding keys.
The topic exchange returns all matched binding keys by remembering the
edges walked down to the leaves. As an optimisation, only for MQTT
queues are binding keys being returned. This does add a small dependency
from app rabbit to app rabbitmq_mqtt which is not optimal. However, this
dependency should be simple to remove when omitting this optimisation.
Another important feature of this commit is persisting subscription
options and subscription identifiers because they are part of the
MQTT 5.0 session state.
In MQTT v3 and v4, the only subscription information that were part of
the session state was the topic filter and the QoS level.
Both information were implicitly stored in the form of bindings:
The topic filter as the binding key and the QoS level as the destination
queue name of the binding.
For MQTT v5 we need to persist more subscription information.
From a domain perspective, it makes sense to store subscription options
as part of subscriptions, i.e. bindings, even though they are currently
not used in routing.
Therefore, this commits stores subscription options as binding arguments.
Storing subscription options as binding arguments comes in turn with
new challenges: How to handle mixed version clusters and upgrading an
MQTT session from v3 or v4 to v5?
Imagine an MQTT client connects via v5 with Session Expiry Interval > 0
to a new node in a mixed version cluster, creates a subscription,
disconnects, and subsequently connects via v3 to an old node. The
client should continue to receive messages.
To simplify such edge cases, this commit introduces a new feature flag
called mqtt_v5. If mqtt_v5 is disabled, clients cannot connect to
RabbitMQ via MQTT 5.0.
This still doesn't entirely solve the problem of MQTT session upgrades
(v4 to v5 client) or session downgrades (v5 to v4 client).
Ideally, once mqtt_v5 is enabled, all MQTT bindings contain non-empty binding
arguments. However, this will require a feature flag migration function
to modify all MQTT bindings. To be more precise, all MQTT bindings need
to be deleted and added because the binding argument is part of the
Mnesia table key.
Since feature flag migration functions are non-trivial to implement in
RabbitMQ (they can run on every node multiple times and concurrently),
this commit takes a simpler approach:
All v3 / v4 sessions keep the empty binding argument [].
All v5 sessions use the new binding argument [#mqtt_subscription_opts{}].
This requires only handling a session upgrade / downgrade by
creating a binding (with the new binding arg) and deleting the old
binding (with the old binding arg) when processing the CONNECT packet.
Note that such session upgrades or downgrades should be rather rare in
practice. Therefore these binding transactions shouldn't hurt peformance.
The No Local option is implemented within the MQTT publishing connection
process: The message is not sent to the MQTT destination if the
destination queue name matches the current MQTT client ID and the
message was routed due to a subscription that has the No Local flag set.
This avoids unnecessary traffic on the MQTT queue.
The alternative would have been that the "receiving side" (same process)
filters the message out - which would have been more consistent in how
Retain As Published and Subscription Identifiers are implemented, but
would have caused unnecessary load on the MQTT queue.
1. Shrinking times out if there is an error, therefore remove the 60
seconds Bazel timeout by using a medium size bazel test suite.
2. The MQTT 5.0 spec mandates for binary data types and UTF 8 string
data types to have values of maximum 65,535 bytes.
Therefore, ensure this test suite does not generate data greater than
that limit.
- when clients connect with a duplicate client id;
disconnect with reason code session taken over 142
- when keep alive has timed out;
disconnect with reason code keep alive timeout 141
All MQTT packets that can be sent in both directions (from client to
server and server to client) are tested in packet_prop_SUITE.
The symmetric property is very concise because encoding and then decoding an
MQTT packet should yield the original MQTT packet.
The input data variety of the previous example based tests was very
small.
- mqtt v5 has more descriptive return values for suback
- added two possible failure reason codes for suback packet
one for permission error, another for quota exceeded error
- modified auth suite to assert on reason codes for v5
- no new test case since failures were already covered
- rename processor state prefetch to receive_maximum
to better match property name for mqtt 5
- defaults to 10 (as previously) when not set
not saved in session state, configuration is per
connection
Allow Session Expiry Interval to be changed when client DISCONNECTs.
Deprecate config subscription_ttl in favour of max_session_expiry_interval_secs
because the Session Expiry Interval will also apply to publishers that
connect with a will message and will delay interval.
"The additional session state of an MQTT v5 server includes:
* The Will Message and the Will Delay Interval
* If the Session is currently not connected, the time at which the Session
will end and Session State will be discarded."
The Session Expiry Interval picked by the server and sent to the client
in the CONNACK is the minimum of max_session_expiry_interval_secs and
the requested Session Expiry Interval by the client in CONNECT.
This commit favours dynamically changing the queue argument x-expires
over creating millions of different policies since that many policies
will come with new scalability issues.
Dynamically changing queue arguments is not allowed by AMQP 0.9.1
clients. However, it should be perfectly okay for the MQTT plugin to do
so for the queues it manages. MQTT clients are not aware that these
queues exist.
If a Server receives a CONNECT packet containing a Will QoS that
exceeds its capabilities, it MUST reject the connection. It SHOULD
use a CONNACK packet with Reason Code 0x9B (QoS not supported) as
described in section 4.13 Handling errors, and MUST close the Network Connection
MQTT v5 allows client and server to negatively ack a message by setting
a reason code of 128 or greater indicating failure.
"If PUBACK or PUBREC is received containing a Reason Code of 0x80 or greater
the corresponding PUBLISH packet is treated as acknowledged, and MUST NOT be
retransmitted [MQTT-4.4.0-2]."
Even though the spec prohibits resending such messages, if a client does
not accept a message, RabbitMQ can still dead letter the message.
MQTT v5 spec:
"If the current retained message for a Topic expires, it is discarded
and there will be no retained message for that topic."
This commit also supports Message Expiry Interval for retained messages
when a node is restarted.
Therefore, the insertion timestamp needs to be stored on disk.
Upon recovery, the Erlang timers are re-created.
- "If the Server included a Maximum QoS in its CONNACK response
to a Client and it receives a PUBLISH packet with a QoS greater than this
then it uses DISCONNECT with Reason Code 0x9B (QoS not supported)"
- only affects mqtt v5, server max qos is 1
This commit does not yet implement Message Expiry Interval of
* retained messages: "If the current retained message for a Topic
expires, it is discarded and there will be no retained message for
that topic."
"Retained messages do not form part of the Session State in the Server,
they are not deleted as a result of a Session ending."
Both retained message stores ETS and DETS implement recovery.
This commit adds a test that recovery works as intended.
"Allow the Client and Server to independently specify the maximum
packet size they support. It is an error for the session partner
to send a larger packet."
This commit implements the part where the Server specifies the maximum
packet size.
"In the case of an error in a CONNECT packet it MAY send a CONNACK
packet containing the Reason Code, before closing the Network
Connection. In the case of an error in any other packet it SHOULD send a
DISCONNECT packet containing the Reason Code before closing the Network
Connection."
This commit implements only the "SHOULD" (second) part, not the "MAY"
(first) part.
There are now 2 different global wide MQTT settings on the server:
1. max_packet_size_unauthenticated which applies to the CONNECT packet
(and maybe AUTH packet in the future)
2. max_packet_size_authenticated which applies to all other MQTT
packets (that is, after the client successfully authenticated).
These two settings will apply to all MQTT versions.
In MQTT v5, if a non-CONNECT packet is too large, the server will send a
DISCONNECT packet to the client with Reason Code "Packet Too Large"
before closing the network connection.
"Allow the Client and Server to independently specify the maximum
packet size they support. It is an error for the session partner
to send a larger packet."
This commit implements the part where the Client specifies the maximum
packet size.
As per protocol spec, instead of sending, the server drops the MQTT packet
if it's too large.
A debug message is logged for "infrequent" packet types.
For PUBLISH packets, the messages is rejected to the queue such that it
will be dead lettered, if dead lettering is configured.
At the very least, Prometheus metrics for dead lettered messages will
be increased, even if dead lettering is not configured.
David Ansari
dependabot[bot]
Jean-Sébastien Pédron
Michael Klishin
Rin Kuryloski
LoisSotoLopez
Michael Klishin
Arnaud Cogoluègnes
Karl Nilsson
Diana Parra Corbacho
Loïc Hoguin
Chunyi Lyu