[BUG] SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder"

[reta]

Description

Interesting issue was reported recently. The OpenSearch core does not use SLF4J (but LOG4J2) however some plugins do:

./plugins/opensearch-ml/slf4j-api-1.7.36.jar
./plugins/opensearch-security/slf4j-api-1.7.30.jar
./plugins/opensearch-alerting/slf4j-api-1.7.30.jar
./plugins/opensearch-sql/slf4j-api-1.7.36.jar
./plugins/opensearch-sql/slf4j-reload4j-1.7.36.jar

The security plugin bundles slf4j-api but there is no binder to bridge SLF4J to LOG4J2. As the result, the following warnings prints out on startup:

[2023-03-17T14:00:00,953][WARN ][stderr                   ] [host] SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".                  
[2023-03-17T14:00:00,954][WARN ][stderr                   ] [host] SLF4J: Defaulting to no-operation (NOP) logger implementation                                         
[2023-03-17T14:00:00,954][WARN ][stderr                   ] [host] SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.                                                                                                                                                                                                                  
[2023-03-17T14:00:00,965][INFO ][o.o.s.s.t.SSLConfig      ] [host] SSL dual mode is disabled                                                            

Issues Resolved

Closes opensearch-project/OpenSearch#6663

Testing

The integration test configuration included log4j-slf4j-impl so the issue didn't manifest, but when only tests are run, same message in error log:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

Check List

• New functionality includes testing
• New functionality has been documented
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
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[DarshitChanpura]

Nice find @reta!

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-2.x 2.x
# Navigate to the new working tree
cd .worktrees/backport-2.x
# Create a new branch
git switch --create backport/backport-2564-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 575c2bc1e7283398ef448c404f480bd7b1eddef5
# Push it to GitHub
git push --set-upstream origin backport/backport-2564-to-2.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-2564-to-2.x.