Hi! I have an Elixir application that is ingesting messages from a queue (AWS SQS). It is based off this design that uses GenStage. The design is as follows: GenStage Producer that fetches messages from the queue GenStage Consumer that subscribes to Producer, receives the queue message and delet…

It may be a library that you invoke from the consumer that is sending the consumer processes unwanted messages. For example, maybe you are calling ExAWS.foo(...) and that is storing the consumer process which eventually leaks a message. Not saying it is ExAWS though, just an example.

One idea is to match on the message and use Port.info on the port and Process.info on the pid and then log the results so you can read it later on. That should give you more hints about which process is leaking them.

That makes sense. Thanks for the leads! I’ll continue investigating and will update with any progress made.

Update on the investigation - it looks like calling Port.info and Process.info on the port and pid result in nil. It looks like the processes have died by the time the message is handled…

What is your erlang version? Erlang 19 has an issue with broken ssl. I’ve run into a similar issue which was fixed when I used the proper tls version :‘tlsv1.2’ ( GitHub - edgurgel/httpoison: Yet Another HTTP client for Elixir powered by hackney · GitHub )

Unfortunately I’m on Erlang 20, I don’t know if that issue applies..

Did you find any solution to this issue? I’ve just encountered the same issue in a Genserver that consumes SQS messages using only ExAws.request()

I believe the reason was the one mentioned above. Something is doing a request using SSL, then the connection is closed, and that leaks the ssl_closed message. The best option is to track whatever is leaking the message and fix the leakage but the leakage in itself shouldn’t be harmful.

We noticed this behavior appearing after upgrading to OTP 21.2 (also using ExAWS with SQS). Upgrading to 21.2.3+ reduced the occurances but didn’t fix it completely yet. Some related pointers: [image] ERL-371: In {active, once}, ssl_closed message is received before final data... Origi…

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GenStage - Unexpected :ssl_closed message

Questions & Help Questions

andersonmcook February 6, 2019, 7:54pm 9

I’m in the same boat, as well, with SQS.