shutdown metrics actors more gracefully #4396
Open
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
On shutdown, Play sends the metrics actors a shutdown message, but as it uses an 'ask', it waits for a response. When no response arrives, it assumes something has gone wrong and shuts down with a more severe error. In fact nothing has gone wrong (usually), we simply don't bother to send a response. Let's do that, both to be graceful, and to enable slightly faster shutdowns
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
What does this change?
On shutdown, Play sends the metrics actors a shutdown message, but as it uses an 'ask', it waits for a response. When no response arrives, it assumes something has gone wrong and shuts down with a more severe error. Sometimes (possibly not always?) this can also interrupt Play's dev mode (recompiling and restarting the app on code changes).
In fact nothing has gone wrong (usually), we simply don't bother to send a response. Let's do that, both to be graceful, and to enable slightly faster shutdowns. The actual message sent is unimportant, as the requester does nothing with it, so send Unit.
How should a reviewer test this change?
Run locally, then stop the app. Does the app finish faster? Do the logs contain fewer shutdown related errors. (Currently some will end with errors that an actor did not respond within 5 seconds).
How can success be measured?
Faster shutdowns, fewer errors, more uninterrupted dev mode.
Who should look at this?
Tested? Documented?