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rabbitmq / rabbitmq-erlang-client

Erlang client for RabbitMQ
https://www.rabbitmq.com/
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Fix channels being killed on connection close #90

Closed dumbbell closed 7 years ago

dumbbell commented 7 years ago

When the server initiates an AMQP connection close, it sends a Connection.Close frame to the client. When it receives one, the Erlang client amqp_gen_connection process does the following steps:

  1. It notifies the amqp_channels_manager process, asking channels to be terminated.
  2. It waits for channels to terminate.

Here, the channels are expected to terminate before the TCP connection is closed. When this happens in this order, Everything Is Fine™.

However, when the TCP connection is closed before channel processes had a chance to terminate, the connection process exits. Because the the amqp_channel_sup supervisor, managed by the amqp_channel_sup_sup supervisor, has a restart strategy of brutal_kill, this supervisor and all its children (including the channel process) are killed.

From the rabbitmq-federation plugin PoV, the link process crashes with the reason {upstream_channel_down, killed} or {downstream_channel_down, killed}.

michaelklishin commented 7 years ago

I recall we had to fix a very similar issue in the server where channel shutdown and socket termination messages competed and produced confusing connection process crashes. So this makes sense 👍.