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The correct format is:
```
-export(Functions).
```
ELP detected this malformed syntax.
Interestingly, prior to this commit, the functions were still exported:
```
rabbitmq_amqp_address:module_info(exports).
[{exchange,1},
{exchange,2},
{queue,1},
{module_info,0},
{module_info,1}]
```
The correct format is:
```
-export(Functions).
```
ELP detected this malformed syntax.
Interestingly, prior to this commit, the functions were still exported:
```
rabbitmq_amqp_address:module_info(exports).
[{exchange,1},
{exchange,2},
{queue,1},
{module_info,0},
{module_info,1}]
```
## What?
This commit determines the queue topology without checking the queue type.
## Why?
This way, checking leader and replicas works the same across all queue
types without the need to introduce other rabbit_queue_type behaviour as
suggested in other PRs.
## How?
pid is the leader, nodes in queue_type_states are the members/replicas.
This commit results in an unknown stream leader during queue
declaration. However the correct leader will be returned eventually when
calling GET on the stream.
Bump the timeout for management operations and link attachments from 20s
to 30s. We've seen timeouts in CI.
We bump the poll interval of the `?awaitMatch` macro because CI
sometimes flaked by crashing in
0e803de6dd/deps/rabbitmq_amqp_client/src/rabbitmq_amqp_client.erl (L411)
which indicates that the client lib received a response from a previous
request.
This commit fixes a bug in the Erlang AMQP 1.0 client.
Prior to this commit, to repro this bug:
1. Send more than 2^16 messages to a queue.
2. Grant more than a total of 2^16 link credit initially (on a single link
or across multiple links) on a single session without any
auto or manual link credit renewal.
The expectation is that thanks to sufficiently granted initial link-credit,
the client will receive all messages.
However, consumption stops after exactly 2^16-1 messages.
That's because the client lib was never sending a flow frame to the server.
So, after the client received all 2^16-1 messages (the initial
incoming-window set by the client), the server's remote-incoming-window
reached 0 causing the server to stop delivering messages.
The expectation is that the client lib automatically handles session
flow control without any manual involvement of the client app.
This commit implements this fix:
* We keep the server's remote-incoming window always large by default as
explained in https://www.rabbitmq.com/blog/2024/09/02/amqp-flow-control#incoming-window
* Hence, the client lib sets its incoming-window to 100,000 initially.
* The client lib tracks its incoming-window decrementing it by 1 for
every transfer it received. (This wasn't done prior to this commit.)
* Whenever this window shrinks below 50,000, the client sends a flow
frame without any link information widening its incoming-window back to 100,000.
* For test cases (maybe later for apps as well), there is a new function
`amqp10_client_session:flow/3`, which allows for a test case to do manual
session flow control. Its API is designed very similar to
`amqp10_client_session:flow_link/4` in that the test can optionally request
the lib to auto widen the session window whenever it falls below a certain threshold.
Transient (i.e. `durable=false`) exchanges and queues are deprecated.
Khepri will store all entities durably.
(Even exclusive queues will be stored durably. Exclusive queues are
still deleted when the declaring connection is closed.)
Similar to how the RabbitMQ AMQP 1.0 Java client already disallows the
creation of transient exchanges and queues, this commit will prohibit
the declaration of transient exchanges and queues in the RabbitMQ
AMQP 1.0 Erlang client starting with RabbitMQ 4.1.
Closes#9259.
## What?
Allow an AMQP 1.0 client to renew an OAuth 2.0 token before it expires.
## Why?
This allows clients to keep the AMQP connection open instead of having
to create a new connection whenever the token expires.
## How?
As explained in https://github.com/rabbitmq/rabbitmq-server/issues/9259#issuecomment-2437602040
the client can `PUT` a new token on HTTP API v2 path `/auth/tokens`.
RabbitMQ will then:
1. Store the new token on the given connection.
2. Recheck access to the connection's vhost.
3. Clear all permission caches in the AMQP sessions.
4. Recheck write permissions to exchanges for links publishing to
RabbitMQ, and recheck read permissions from queues for links
consuming from RabbitMQ. The latter complies with the user
expectation in #11364.
As described in https://github.com/rabbitmq/rabbitmq-server/issues/12413#issuecomment-2385379386
test case queue_topology flaked in CI with the following error:
```
rabbitmq_amqp_client > management_SUITE > cluster_size_3 > queue_topology
#1. {error,{test_case_failed,{824,
<<"rmq-ct-cluster_size_3-1-21000@localhost">>}}}
```
This flake could not be reproduced locally (neither with Mnesia nor with Khepri).
This commit notifies the client app with the AMQP performative if
connection config `notify_with_performative` is set to `true`.
This allows the client app to learn about all fields including
properties and capabilities returned by the AMQP server.
This has no real impact on performance[1] but should
make it clear which application can run the broker
and/or publish to Hex.pm. In particular, applications
that we can't run the broker from will now give up
early if we try to.
Note that while the broker can't normally run from the
amqp_client application's directory, it can run from
tests and some of the tests start the broker.
[1] on my machine
This commit is a follow up of https://github.com/rabbitmq/rabbitmq-server/pull/11604
This commit changes the AMQP address format v2 from
```
/e/:exchange/:routing-key
/e/:exchange
/q/:queue
```
to
```
/exchanges/:exchange/:routing-key
/exchanges/:exchange
/queues/:queue
```
Advantages:
1. more user friendly
2. matches nicely with the plural forms of HTTP API v1 and HTTP API v2
This plural form is still non-overlapping with AMQP address format v1.
Although it might feel unusual at first to send a message to `/queues/q1`,
if you think about `queues` just being a namespace or entity type, this
address format makes sense.
to distinguish between v1 and v2 address formats.
Previously, v1 and v2 address formats overlapped and behaved differently
for example for:
```
/queue/:queue
/exchange/:exchange
```
This PR changes the v2 format to:
```
/e/:exchange/:routing-key
/e/:exchange
/q/:queue
```
to distinguish between v1 and v2 addresses.
This allows to call `rabbit_deprecated_features:is_permitted(amqp_address_v1)`
only if we know that the user requests address format v1.
Note that `rabbit_deprecated_features:is_permitted/1` should only
be called when the old feature is actually used.
Use percent encoding / decoding for address URI format v2.
This allows to use any UTF-8 encoded characters including slashes (`/`)
in routing keys, exchange names, and queue names and is more future
safe.
We don't need to duplicate so many patterns in so many
files since we have a monorepo (and want to keep it).
If I managed to miss something or remove something that
should stay, please put it back. Note that monorepo-wide
patterns should go in the top-level .gitignore file.
Other .gitignore files are for application or folder-
specific patterns.
## 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.
Apply the following PR feedback:
> The data returned is strongly validated; there can't be an extra unknown field.
> I would suggest ignoring field names that are not known as this allows for better
> extensibility. On the other hand, there should be a check that all required fields
> are found.
## What?
* Allow AMQP 1.0 clients to dynamically create and delete RabbitMQ
topologies (exchanges, queues, bindings).
* Provide an Erlang AMQP 1.0 client that manages topologies.
## Why?
Today, RabbitMQ topologies can be created via:
* [Management HTTP API](https://www.rabbitmq.com/docs/management#http-api)
(including Management UI and
[messaging-topology-operator](https://github.com/rabbitmq/messaging-topology-operator))
* [Definition Import](https://www.rabbitmq.com/docs/definitions#import)
* AMQP 0.9.1 clients
Up to RabbitMQ 3.13 the RabbitMQ AMQP 1.0 plugin auto creates queues
and bindings depending on the terminus [address
format](https://github.com/rabbitmq/rabbitmq-server/tree/v3.13.x/deps/rabbitmq_amqp1_0#routing-and-addressing).
Such implicit creation of topologies is limiting and obscure.
For some address formats, queues will be created, but not deleted.
Some of RabbitMQ's success is due to its flexible routing topologies
that AMQP 0.9.1 clients can create and delete dynamically.
This commit allows dynamic management of topologies for AMQP 1.0 clients.
This commit builds on top of Native AMQP 1.0 (PR #9022) and will be
available in RabbitMQ 4.0.
## How?
This commits adds the following management operations for AMQP 1.0 clients:
* declare queue
* delete queue
* purge queue
* bind queue to exchange
* unbind queue from exchange
* declare exchange
* delete exchange
* bind exchange to exchange
* unbind exchange from exchange
Hence, at least the AMQP 0.9.1 management operations are supported for
AMQP 1.0 clients.
In addition the operation
* get queue
is provided which - similar to `declare queue` - returns queue
information including the current leader and replicas.
This allows clients to publish or consume locally on the node that hosts
the queue.
Compared to AMQP 0.9.1 whose commands and command fields are fixed, the
new AMQP Management API is extensible: New operations and new fields can
easily be added in the future.
There are different design options how management operations could be
supported for AMQP 1.0 clients:
1. Use a special exchange type as done in https://github.com/rabbitmq/rabbitmq-management-exchange
This has the advantage that any protocol client (e.g. also STOMP clients) could
dynamically manage topologies. However, a special exchange type is the wrong abstraction.
2. Clients could send "special" messages with special headers that the broker interprets.
This commit decided for a variation of the 2nd option using a more
standardized way by re-using a subest of the following latest AMQP 1.0 extension
specifications:
* [AMQP Request-Response Messaging with Link Pairing Version 1.0 - Committee Specification 01](https://docs.oasis-open.org/amqp/linkpair/v1.0/cs01/linkpair-v1.0-cs01.html) (February 2021)
* [HTTP Semantics and Content over AMQP Version 1.0 - Working Draft 06](https://groups.oasis-open.org/higherlogic/ws/public/document?document_id=65571) (July 2019)
* [AMQP Management Version 1.0 - Working Draft 16](https://groups.oasis-open.org/higherlogic/ws/public/document?document_id=65575) (July 2019)
An important goal is to keep the interaction between AMQP 1.0 client and RabbitMQ
simple to increase usage, development and adoptability of future RabbitMQ AMQP 1.0
client library wrappers.
The AMQP 1.0 client has to create a link pair to the special `/management` node.
This allows the client to send and receive from the management node.
Similar to AMQP 0.9.1, there is no need for a reply queue since the reply
will be sent directly to the client.
Requests and responses are modelled via HTTP, but sent via AMQP using
the `HTTP Semantics and Content over AMQP` extension (henceforth `HTTP
over AMQP` extension).
This commit tries to follow the `HTTP over AMQP` extension as much as
possible but deviates where this draft spec doesn't make sense.
The projected mode §4.1 is used as opposed to tunneled mode §4.2.
A named relay `/management` is used (§6.3) where the message field `to` is the URL.
Deviations are
* §3.1 mandates that URIs are not encoded in an AMQP message.
However, we percent encode URIs in the AMQP message. Otherwise there
is for example no way to distinguish a `/` in a queue name from the
URI path separator `/`.
* §4.1.4 mandates a data section. This commit uses an amqp-value section
as it's a better fit given that the content is AMQP encoded data.
Using an HTTP API allows for a common well understood interface and future extensibility.
Instead of re-using the current RabbitMQ HTTP API, this commit uses a
new HTTP API (let's call it v2) which could be used as a future API for
plain HTTP clients.
### HTTP API v1
The current HTTP API (let's call it v1) is **not** used since v1
comes with a couple of weaknesses:
1. Deep level of nesting becomes confusing and difficult to manage.
Examples of deep nesting in v1:
```
/api/bindings/vhost/e/source/e/destination/props
/api/bindings/vhost/e/exchange/q/queue/props
```
2. Redundant endpoints returning the same resources
v1 has 9 endpoints to list binding(s):
```
/api/exchanges/vhost/name/bindings/source
/api/exchanges/vhost/name/bindings/destination
/api/queues/vhost/name/bindings
/api/bindings
/api/bindings/vhost
/api/bindings/vhost/e/exchange/q/queue
/api/bindings/vhost/e/exchange/q/queue/props
/api/bindings/vhost/e/source/e/destination
/api/bindings/vhost/e/source/e/destination/props
```
3. Verbs in path names
Path names should be nouns instead.
v1 contains verbs:
```
/api/queues/vhost/name/get
/api/exchanges/vhost/name/publish
```
### AMQP Management extension
Only few aspects of the AMQP Management extension are used.
The central idea of the AMQP management spec is **dynamic discovery** such that broker independent AMQP 1.0
clients can discover objects, types, operations, and HTTP endpoints of specific brokers.
In fact, clients are only conformant if:
> All request addresses are dynamically discovered starting from the discovery document.
> A requesting container MUST NOT use fixed assumptions about the addressing structure of the management API.
While this is a nice and powerful idea, no AMQP 1.0 client and no AMQP 1.0 server implement the
latest AMQP 1.0 management spec from 2019, partly presumably due to its complexity.
Therefore, the idea of such dynamic discovery has failed to be implemented in practice.
The AMQP management spec mandates that the management endpoint returns a discovery document containing
broker specific collections, types, configuration, and operations including their endpoints.
The API endpoints of the AMQP management spec are therefore all designed around dynamic discovery.
For example, to create either a queue or an exchange, the client has to
```
POST /$management/entities
```
which shows that the entities collection acts as a generic factory, see section 2.2.
The server will then create the resource and reply with a location header containing a URI pointing to the resource.
For RabbitMQ, we don’t need such a generic factory to create queues or exchanges.
To list bindings for a queue Q1, the spec suggests
```
GET /$management/Queues/Q1/$management/entities
```
which again shows the generic entities endpoint as well as a `$management` endpoint under Q1 to
allow a queue to return a discovery document.
For RabbitMQ, we don’t need such generic endpoints and discovery documents.
Given we aim for our own thin RabbitMQ AMQP 1.0 client wrapper libraries which expose
the RabbitMQ model to the developer, we can directly use fixed HTTP endpoint assumptions
in our RabbitMQ specific libraries.
This is by far simpler than using the dynamic endpoints of the management spec.
Simplicity leads to higher adoption and enables more developers to write RabbitMQ AMQP 1.0 client
library wrappers.
The AMQP Management extension also suffers from deep level of nesting in paths
Examples:
```
/$management/Queues/Q1/$management/entities
/$management/Queues/Q1/Bindings/Binding1
```
as well as verbs in path names: Section 7.1.4 suggests using verbs in path names,
for example “purge”, due to the dynamic operations discovery document.
### HTTP API v2
This commit introduces a new HTTP API v2 following best practices.
It could serve as a future API for plain HTTP clients.
This commit and RabbitMQ 4.0 will only implement a minimal set of
HTTP API v2 endpoints and only for HTTP over AMQP.
In other words, the existing HTTP API v1 Cowboy handlers will continue to be
used for all plain HTTP requests in RabbitMQ 4.0 and will remain untouched for RabbitMQ 4.0.
Over time, after 4.0 shipped, we could ship a pure HTTP API implementation for HTTP API v2.
Hence, the new HTTP API v2 endpoints for HTTP over AMQP should be designed such that they
can be re-used in the future for a pure HTTP implementation.
The minimal set of endpoints for RabbitMQ 4.0 are:
``
GET / PUT / DELETE
/vhosts/:vhost/queues/:queue
```
read, create, delete a queue
```
DELETE
/vhosts/:vhost/queues/:queue/messages
```
purges a queue
```
GET / DELETE
/vhosts/:vhost/bindings/:binding
```
read, delete bindings
where `:binding` is a binding ID of the following path segment:
```
src=e1;dstq=q2;key=my-key;args=
```
Binding arguments `args` has an empty value by default, i.e. there are no binding arguments.
If the binding includes binding arguments, `args` will be an Erlang portable term hash
provided by the server similar to what’s provided in HTTP API v1 today.
Alternatively, we could use an arguments scheme of:
```
args=k1,utf8,v1&k2,uint,3
```
However, such a scheme leads to long URIs when there are many binding arguments.
Note that it’s perfectly fine for URI producing applications to include URI
reserved characters `=` / `;` / `,` / `$` in a path segment.
To create a binding, the client therefore needs to POST to a bindings factory URI:
```
POST
/vhosts/:vhost/bindings
```
To list all bindings between a source exchange e1 and destination exchange e2 with binding key k1:
```
GET
/vhosts/:vhost/bindings?src=e1&dste=e2&key=k1
```
This endpoint will be called by the RabbitMQ AMQP 1.0 client library to unbind a
binding with non-empty binding arguments to get the binding ID before invoking a
```
DELETE
/vhosts/:vhost/bindings/:binding
```
In future, after RabbitMQ 4.0 shipped, new API endpoints could be added.
The following is up for discussion and is only meant to show the clean and simple design of HTTP API v2.
Bindings endpoint can be queried as follows:
to list all bindings for a given source exchange e1:
```
GET
/vhosts/:vhost/bindings?src=e1
```
to list all bindings for a given destination queue q1:
```
GET
/vhosts/:vhost/bindings?dstq=q1
```
to list all bindings between a source exchange e1 and destination queue q1:
```
GET
/vhosts/:vhost/bindings?src=e1&dstq=q1
```
multiple bindings between source exchange e1 and destination queue q1 could be deleted at once as follows:
```
DELETE /vhosts/:vhost/bindings?src=e1&dstq=q1
```
GET could be supported globally across all vhosts:
```
/exchanges
/queues
/bindings
```
Publish a message:
```
POST
/vhosts/:vhost/queues/:queue/messages
```
Consume or peek a message (depending on query parameters):
```
GET
/vhosts/:vhost/queues/:queue/messages
```
Note that the AMQP 1.0 client omits the `/vhost/:vhost` path prefix.
Since an AMQP connection belongs to a single vhost, there is no need to
additionally include the vhost in every HTTP request.
Pros of HTTP API v2:
1. Low level of nesting
Queues, exchanges, bindings are top level entities directly under vhosts.
Although the HTTP API doesn’t have to reflect how resources are stored in the database,
v2 does nicely reflect the Khepri tree structure.
2. Nouns instead of verbs
HTTP API v2 is very simple to read and understand as shown by
```
POST /vhosts/:vhost/queues/:queue/messages to post messages, i.e. publish to a queue.
GET /vhosts/:vhost/queues/:queue/messages to get messages, i.e. consume or peek from a queue.
DELETE /vhosts/:vhost/queues/:queue/messages to delete messages, i.e. purge a queue.
```
A separate new HTTP API v2 allows us to ship only handlers for HTTP over AMQP for RabbitMQ 4.0
and therefore move faster while still keeping the option on the table to re-use the new v2 API
for pure HTTP in the future.
In contrast, re-using the HTTP API v1 for HTTP over AMQP is possible, but dirty because separate handlers
(HTTP over AMQP and pure HTTP) replying differently will be needed for the same v1 endpoints.
David Ansari
Aitor Perez
Arnaud Cogoluègnes
Michael Klishin
Loïc Hoguin
Michael Klishin