rabbit_logger_exchange_h: Do not re-enter itself (backport #14796) #14804
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[Why] Publishing a log message to an exchange might trigger other messages to be logged. This caused two issues: 1. the exchange logger re-entering itself in an infinite loop 2. if the message is logged from a gen_server-like process, like a Ra server, that is involved in the publishing code path, the process might call itself, leading to a blocked situation [How] The first issue is fixed with a variable stored in the process dictionary by the `log/2` function. This way, the function can check if it is called from itself because the first incantation stored a variable there. The second issue is fixed by publishing the message asynchronously from a separate process. This is ok because we don't care if the publish was successful or not. We re-use the process that was started initially to declare the exchange. Fixes #14069. (cherry picked from commit 7cc0aa9)
[Why] It makes debugging easier, especially now that this process does more than the initial setup: it acts as the actual publisher of the log messages. (cherry picked from commit 73a41cc)
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Why
Publishing a log message to an exchange might trigger other messages to be logged. This caused two issues:
How
The first issue is fixed with a variable stored in the process dictionary by the
log/2function. This way, the function can check if it is called from itself because the first incantation stored a variable there.The second issue is fixed by publishing the message asynchronously from a separate process. This is ok because we don't care if the publish was successful or not. We re-use the process that was started initially to declare the exchange.
Fixes #14069.
This is an automatic backport of pull request #14796 done by Mergify.