Fix a possible deadlock when `OAuth2Client` is used with `RetryingClient`

[ikhoon]

Motivation:

When OAuth2Client fails to acquire a granted access token, it directly returns a failed response. As the response is returned, RequestLog is not completed.

RetryingClient waits for some properties of RequestLog to be completed. Therefore, the incomplete RequestLog causes RetryingClient to get stuck.

This PR is a temporary workaround to fix the problem. The deadlock phenomenon will occur easily if a decorator returns a response directly. I created #5714 in which I will try to solve this problem ultimately.

Modifications:

• If getAccessToken() completes exceptionally, completes the log and then returns a failed response.

Result:

Fixed a bug where RetryingClient gets to deadlock when OAuth2Client fails to obtain an access token.

[jrhee17]

Just to make sure, am I understanding correctly that this issue is still a problem even if RetryingClient isn't in the decorator chain? (logs not completing could potentially pose a problem not restricted to retrying)

[github-actions[bot]]

🔍 Build Scan® (commit: 631a878e1532ea8cd794404bcf3ac61646e0c42a)

Job name	Status	Build Scan®
build-windows-latest-jdk-21	✅	https://ge.armeria.dev/s/vpggi5w3fsxhc
build-self-hosted-unsafe-jdk-8	✅	https://ge.armeria.dev/s/5ky773jpyr5xg
build-self-hosted-unsafe-jdk-21-snapshot-blockhound	✅	https://ge.armeria.dev/s/q3dp7tkaqyrn4
build-self-hosted-unsafe-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/bf5nnb222zvzq
build-self-hosted-unsafe-jdk-17-min-java-11	✅	https://ge.armeria.dev/s/zltqipovbsev6
build-self-hosted-unsafe-jdk-17-leak	✅	https://ge.armeria.dev/s/nv2n5igzcifpw
build-self-hosted-unsafe-jdk-11	✅	https://ge.armeria.dev/s/hkn6nump2mvue
build-macos-12-jdk-21	✅	https://ge.armeria.dev/s/tklm7r3hevbm6

[ikhoon]

am I understanding correctly that this issue is still a problem even if RetryingClient isn't in the decorator chain? (logs not completing could potentially pose a problem not restricted to retrying)

Right. RequestLog isn't completed regardless of RetryingClient. So RequestLog related operations such as LoggingClient and MetricCollectingClient do not work with the failed request before.

[ikhoon]

I try to complete RequestLog if a response is returned by a decorator. I am not confident with the workaround though. I still need to come up with new ideas for the problem. https://github.com/line/armeria/pull/5714/files#diff-f2eb8203256e0ecc52bed39c1f10697323d973d9f15c83096214794378fb197fR174-R178

[jrhee17]

Thanks! I was just curious while writing the weekly report. Will also take a look at the approach in the other PR later 😃

[minwoox]

@ikhoon 👍 👍 👍