Bug #21621: async_msgr: bind must be called before registering any dispatcher - Messengers - Ceph

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Bug #21621

closed

async_msgr: bind must be called before registering any dispatcher

Added by Ricardo Dias over 6 years ago. Updated about 5 years ago.

Status:

Closed

Priority:

Normal

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Category:

Target version:

% Done:

Source:

Tags:

msgr

Backport:

Regression:

Severity:

3 - minor

Reviewed:

Affected Versions:

ceph-qa-suite:

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Crash signature (v1):

Crash signature (v2):

Description

While building a small client/server example using the Ceph messenger classes, I found that if I register a dispatcher before calling the "Messenger::bind" method on the messenger, the messenger will start the connection processor before having a server socket initialized and will not process any incoming connections on the server socket that is later initialized in the "Messenger::bind" method.

I think this is a weird behavior because I think the most intuitive behavior would be for the programmer to add the dispatchers before binding the messenger to an address.

Is there a good reason for the current behavior? or is this a bug?

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Updated by Haomai Wang over 6 years ago

there exists legacy reason about this. we want to have a quick fail when binding failed instead of exited background.

maybe it's a feature to implement your hope

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Updated by Haomai Wang over 6 years ago

Oh, sorry. I misunderstand the description just now.

YES, you could call Messenger::start instead of bind

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Updated by Ricardo Dias over 6 years ago

Haomai Wang wrote:

Oh, sorry. I misunderstand the description just now.

What I meant was:
When we register a dispatcher before calling "bind", no messages will be processed by the dispatcher. Is this a bug or is this the intended behavior?

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Updated by Sage Weil over 6 years ago

I think it's an oversight. It doesn't matter for most daemons: they don't expect any messages until they've started up and registered themselves with the monitors, so dropping stray messages before that is irrelevant.

For the mons it is a bit nonintuitive, but also harmless, since the mons are written to expect a stream of messages intended for predecessors and will still behave.

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