move render events to after template command#1370
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When using CT as a library, the "standard" way to monitor and know when to exit is to watch for messages on the TemplateRenderedCh(). The problem is that the message is sent down that channel before the commands are run, so the program could exit before the command has run. The problem is more obvious when CT is run in a transient container, where even if the commands are run the container might exit before they finish and they get killed. Moving the render events to after the command avoids these issues (the container exit issue also requires a command_timeout > 0s).
findkim
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Appreciate the context on the use case this solves! The changes makes sense wrt CT running in a transient container.
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I'm going to update the PR to tweak to documentation to mention the 0s/fire-n-forget case. |
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@findkim I updated the PR with the documentation change. |
jasonodonnell
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I tested this functionally by adding varying sleeps as commands, all which ran and then Consul Template notified the render event. Thanks for this fix!
This was referenced May 20, 2020
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When using CT as a library, the "standard" way to monitor and know when
to exit is to watch for messages on the TemplateRenderedCh(). The
problem is that the message is sent down that channel before the
commands are run, so the program could exit before the command has run.
The problem is more obvious when CT is run in a transient container,
where even if the commands are run the container might exit before they
finish and they get killed.
Moving the render events to after the command avoids these issues (the
container exit issue also requires a command_timeout > 0s).
Fixes #1369