## Why?
To introduce AMQP over WebSocket, we will add gun to the Erlang AMQP
1.0 client. We want to add the latest version of gun for this new
feature. Since rabbitmq_peer_discovery_etcd depends on the outdated
eetcd 0.3.6 which in turn depends on the outdated gun 1.3.3, this commit
first upgrades eetcd and gun.
## How?
See https://github.com/zhongwencool/eetcd?tab=readme-ov-file#migration-from-eetcd-03x-to-04x
## Breaking Changes
This commit causes the following breaking change:
`rabbitmq.conf` settings
* `cluster_formation.etcd.ssl_options.fail_if_no_peer_cert`
* `cluster_formation.etcd.ssl_options.dh`
* `cluster_formation.etcd.ssl_options.dhfile`
are unsupported because they are not valid `ssl:tls_client_option()`.
See https://github.com/erlang/otp/issues/7497#issuecomment-1636012198
## What?
Prior to this commit, the `rabbitmq_event_exchange` internally published
always AMQP 0.9.1 messages to the `amq.rabbitmq.event` topic exchange.
This commit allows users to configure the plugin to publish AMQP 1.0
messages instead.
## Why?
Prior to this commit, when an AMQP 1.0 client consumed events,
event properties that are lists were omitted. For example property
`client_properties` of event `connection.created` or property
`arguments` of event `queue.created` were omitted because of the following sequence:
1. The event exchange plugins listens for all kind of internal events.
2. The event exchange plugin re-publishes all events as AMQP 0.9.1 message to the event exchange.
3. Later, when an AMQP 1.0 client consumes this message, the broker must translate the message from AMQP 0.9.1 to AMQP 1.0.
4. This translation follows the rules outlined in https://www.rabbitmq.com/docs/conversions#amqpl-amqp
5. Specifically, in this table the row before the last one describes the rule we're hitting here. It says that if the AMQP 0.9.1
header value is not an `x-` prefixed header and its value is an array or table, then this header is not converted.
That's because AMQP 1.0 application-properties must be simple types as mandated in https://docs.oasis-open.org/amqp/core/v1.0/os/amqp-core-messaging-v1.0-os.html#type-application-properties
## How?
The user can configure the plugin as follows to have the plugin
internally publish AMQP 1.0 messages:
```
event_exchange.protocol = amqp_1_0
```
To support complex types such as lists, the plugin sets all event
properties as AMQP 1.0 message-annotations. The plugin prefixes all message
annotation keys with `x-opt-` to comply with the AMQP 1.0 spec.
## Alternative Design
An alternative design would have been to format all event properties
e.g. as JSON within the message body. However, this breaks routing on
specific event property values via a headers exchange.
## Documentation
https://github.com/rabbitmq/rabbitmq-website/pull/2129
## What?
On the connection page in the Management UI, display detailed session and
link information including:
* Link names
* Link target and source addresses
* Link flow control state
* Session flow control state
* Number of unconfirmed and unacknowledged messages
## How?
A new HTTP API endpoint is added:
```
/connections/:connection_name/sessions
```
The HTTP handler first queries the Erlang connection process to find out about
all session Pids. The handler then queries each Erlang session process
of this connection.
(The table auto-refreshes by default every 5 seconds. The handler querying a single
connection with 60 idle sessions with each 250 links takes ~100 ms.)
For better user experience in the Management UI, this commit also makes the
session process store and expose link names as well as source/target addresses.
Expose the same metrics for AMQP 1.0 connections as for AMQP 0.9.1 connections.
Display the following AMQP 1.0 metrics on the Management UI:
* Network bytes per second from/to client on connections page
* Number of sessions/channels on connections page
* Network bytes per second from/to client graph on connection page
* Reductions graph on connection page
* Garbage colletion info on connection page
Expose the following AMQP 1.0 per-object Prometheus metrics:
* rabbitmq_connection_incoming_bytes_total
* rabbitmq_connection_outgoing_bytes_total
* rabbitmq_connection_process_reductions_total
* rabbitmq_connection_incoming_packets_total
* rabbitmq_connection_outgoing_packets_total
* rabbitmq_connection_pending_packets
* rabbitmq_connection_channels
The rabbit_amqp_writer proc:
* notifies the rabbit_amqp_reader proc if it sent frames
* hibernates eventually if it doesn't send any frames
The rabbit_amqp_reader proc:
* does not emit stats (update ETS tables) if no frames are received
or sent to save resources when there are many idle connections.
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.
Support x-cc message annotation
Support an `x-cc` message annotation in AMQP 1.0
similar to the [CC](https://www.rabbitmq.com/docs/sender-selected) header in AMQP 0.9.1.
The value of the `x-cc` message annotation must by a list of strings.
A message annotation is used since application properties allow only simple types.
Given that the default max_message_size got decreased from 128 MiB to 16
MiB in RabbitMQ 4.0 in https://github.com/rabbitmq/rabbitmq-server/pull/11455,
it makes sense to also decrease the default MQTT Maximum Packet Size from 256 MiB to 16 MiB.
Since this change was missed in RabbitMQ 4.0, it is scheduled for RabbitMQ 4.1.
Michael Klishin
Michael Klishin
Michal Kuratczyk
David Ansari
Michael Klishin
Jean-Sébastien Pédron