Consistently use slf4j/log4j bridge by rjernst · Pull Request #139226 · elastic/elasticsearch

rjernst · 2025-12-09T00:14:05Z

Some 3rd party dependencies use SLF4J but Elasticsearch internally uses log4j. Historically there were problems with using the log4j adapter for SLF4J, but those have gone away with the removal of SecurityManager. This commit updates uses of slf4j to consistently use the log4j bridge. Note that long term we should still aim for something more turnkey so that we don't end up with multiple copies of the bridge jar, but this change at least removes warnings about no SLF4J providers being found.

closes #137556

Some 3rd party dependencies use SLF4J but Elasticsearch internally uses log4j. Historically there were problems with using the log4j adapter for SLF4J, but those have gone away with the removal of SecurityManager. This commit updates uses of slf4j to consistently use the log4j bridge.

elasticsearchmachine · 2025-12-09T00:14:29Z

Pinging @elastic/es-core-infra (Team:Core/Infra)

DaveCTurner

LGTM excellent, confirmed to work with e.g.

diff --git a/modules/repository-s3/src/javaRestTest/java/org/elasticsearch/repositories/s3/RepositoryS3BasicCredentialsRestIT.java b/modules/repository-s3/src/javaRestTest/java/org/elasticsearch/repositories/s3/RepositoryS3BasicCredentialsRestIT.java
index dfe3bbbc2613..8757263427d2 100644
--- a/modules/repository-s3/src/javaRestTest/java/org/elasticsearch/repositories/s3/RepositoryS3BasicCredentialsRestIT.java
+++ b/modules/repository-s3/src/javaRestTest/java/org/elasticsearch/repositories/s3/RepositoryS3BasicCredentialsRestIT.java
@@ -50,6 +50,8 @@ public class RepositoryS3BasicCredentialsRestIT extends AbstractRepositoryS3Rest
         .keystore("s3.client." + CLIENT + ".access_key", ACCESS_KEY)
         .keystore("s3.client." + CLIENT + ".secret_key", SECRET_KEY)
         .setting("s3.client." + CLIENT + ".endpoint", s3Fixture::getAddress)
+        .systemProperty("es.insecure_network_trace_enabled", "true")
+        .setting("logger.org.apache.http.headers", "TRACE")
         .build();

     @ClassRule

DaveCTurner · 2025-12-09T09:16:56Z

NB closes #137556

DaveCTurner · 2025-12-09T09:43:41Z

I proposed a test to verify the logging in repository-s3 since this is something we describe in the docs (incorrectly, today, but we can fix that).

Note that we restrict the AWS SDK v1 loggers in case they expose sensitive information:

elasticsearch/server/src/main/java/org/elasticsearch/common/logging/Loggers.java

Line 49 in a59c182

: List.of("org.apache.http", "com.amazonaws.request");

Should we do that for the AWS SDK v2 loggers too? I.e. everything under software.amazon.awssdk.

DaveCTurner · 2025-12-09T22:19:19Z

.../javaRestTest/java/org/elasticsearch/repositories/s3/RepositoryS3BasicCredentialsRestIT.java

+        .systemProperty("es.insecure_network_trace_enabled", "true")
+        .setting("logger.org.apache.http.headers", "TRACE")


We don't need these here, this was just something I mentioned in a review comment as how I verified by hand that it worked. RepositoryS3WireLoggingRestIT is a much more comprehensive test of this.

It turns out that the Azure SDK logs copiously at `ERROR` level for totally benign events such as a `BlobNotFound` response when trying to delete a blob that has already been deleted. Until elastic#139226 these messages were screamed into the void and caused no issue, but since that change landed we now see them in the server logs too. In due course we'd like to be able to capture these logs at a more appropriate level, maybe `DEBUG`, but in the meantime this commit removes the SLF4J bridge from the `repository-azure` module to redirect them back into the void.

It turns out that the Azure SDK logs copiously at `ERROR` level for totally benign events such as a `BlobNotFound` response when trying to delete a blob that has already been deleted. Until #139226 these messages were screamed into the void and caused no issue, but since that change landed we now see them in the server logs too. In due course we'd like to be able to capture these logs at a more appropriate level, maybe `DEBUG`, but in the meantime this commit removes the SLF4J bridge from the `repository-azure` module to redirect them back into the void.

It turns out that the Azure SDK logs copiously at `ERROR` level for totally benign events such as a `BlobNotFound` response when trying to delete a blob that has already been deleted. Until elastic#139226 these messages were screamed into the void and caused no issue, but since that change landed we now see them in the server logs too. In due course we'd like to be able to capture these logs at a more appropriate level, maybe `DEBUG`, but in the meantime this commit removes the SLF4J bridge from the `repository-azure` module to redirect them back into the void.

It turns out that the Azure SDK logs copiously at `ERROR` level for totally benign events such as a `BlobNotFound` response when trying to delete a blob that has already been deleted. Until #139226 these messages were screamed into the void and caused no issue, but since that change landed we now see them in the server logs too. In due course we'd like to be able to capture these logs at a more appropriate level, maybe `DEBUG`, but in the meantime this commit removes the SLF4J bridge from the `repository-azure` module to redirect them back into the void.

DaveCTurner · 2025-12-23T07:50:00Z

@rjernst I think we're missing backports here, this only seems to be in the 9.3 and main branches at the moment.

rjernst · 2025-12-23T15:04:53Z

This is why we need auto-backport by default 🤦

Some 3rd party dependencies use SLF4J but Elasticsearch internally uses log4j. Historically there were problems with using the log4j adapter for SLF4J, but those have gone away with the removal of SecurityManager. This commit updates uses of slf4j to consistently use the log4j bridge. closes elastic#137556 Co-authored-by: David Turner <david.turner@elastic.co>

rjernst · 2025-12-23T15:37:14Z

9.2: #139950
9.1: #139951
8.19: #139952

* Consistently use slf4j/log4j bridge (#139226) Some 3rd party dependencies use SLF4J but Elasticsearch internally uses log4j. Historically there were problems with using the log4j adapter for SLF4J, but those have gone away with the removal of SecurityManager. This commit updates uses of slf4j to consistently use the log4j bridge. closes #137556 Co-authored-by: David Turner <david.turner@elastic.co> * remove param from main * fix dep * update license * more licenses --------- Co-authored-by: David Turner <david.turner@elastic.co>

* Consistently use slf4j/log4j bridge (#139226) Some 3rd party dependencies use SLF4J but Elasticsearch internally uses log4j. Historically there were problems with using the log4j adapter for SLF4J, but those have gone away with the removal of SecurityManager. This commit updates uses of slf4j to consistently use the log4j bridge. closes #137556 Co-authored-by: David Turner <david.turner@elastic.co> * remove param from main * license update * more licenses --------- Co-authored-by: David Turner <david.turner@elastic.co>

* Consistently use slf4j/log4j bridge (#139226) Some 3rd party dependencies use SLF4J but Elasticsearch internally uses log4j. Historically there were problems with using the log4j adapter for SLF4J, but those have gone away with the removal of SecurityManager. This commit updates uses of slf4j to consistently use the log4j bridge. closes #137556 Co-authored-by: David Turner <david.turner@elastic.co> * fix dep * fix licenses * more licenses * fix compile --------- Co-authored-by: David Turner <david.turner@elastic.co>

rjernst requested a review from a team as a code owner December 9, 2025 00:14

rjernst added :Core/Infra/Logging Log management and logging utilities >refactoring branch:9.2 branch:9.1 branch:8.19 labels Dec 9, 2025

rjernst requested review from DaveCTurner and removed request for a team December 9, 2025 00:14

elasticsearchmachine added Team:Core/Infra Meta label for core/infra team v9.1.9 v9.3.0 v8.19.9 v9.2.3 and removed branch:9.2 branch:9.1 branch:8.19 labels Dec 9, 2025

DaveCTurner approved these changes Dec 9, 2025

View reviewed changes

Add test to verify repository-s3 logging

21d9747

rjernst added 2 commits December 9, 2025 11:14

cleanup licenses

558d776

actually add license files

d575a09

rjernst requested a review from a team as a code owner December 9, 2025 19:26

rjernst added 3 commits December 9, 2025 11:27

remove exclude

d76c5bd

more licenses

f69e181

more tweaks

2e5dd46

DaveCTurner reviewed Dec 9, 2025

View reviewed changes

Fix forbidden APIs violation

a46d127

rjernst added 2 commits December 10, 2025 10:56

Merge branch 'main' into logging/slf4j_bridge

535a1b2

set consistency model

13b8543

rjernst merged commit 9a473e9 into elastic:main Dec 10, 2025
34 checks passed

rjernst deleted the logging/slf4j_bridge branch December 10, 2025 23:03

DaveCTurner mentioned this pull request Dec 18, 2025

Suppress Azure SDK error logs #139729

Merged

DaveCTurner mentioned this pull request Dec 18, 2025

Suppress Azure SDK error logs #139730

Merged

DaveCTurner added v8.19.10 v9.2.4 v9.1.10 and removed v8.19.9 v9.2.3 v9.1.9 labels Jan 7, 2026

This was referenced Jan 13, 2026

[CLEAN] Synthetic Benchmark PR #139226 - Consistently use slf4j/log4j bridge qodo-benchmark/elasticsearch#79

Open

[CORRUPTED] Synthetic Benchmark PR #139226 - Consistently use slf4j/log4j bridge qodo-benchmark/elasticsearch#80

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Consistently use slf4j/log4j bridge#139226

Consistently use slf4j/log4j bridge#139226
rjernst merged 10 commits intoelastic:mainfrom
rjernst:logging/slf4j_bridge

rjernst commented Dec 9, 2025 •

edited

Loading

Uh oh!

elasticsearchmachine commented Dec 9, 2025

Uh oh!

DaveCTurner left a comment

Uh oh!

DaveCTurner commented Dec 9, 2025

Uh oh!

DaveCTurner commented Dec 9, 2025

Uh oh!

DaveCTurner Dec 9, 2025

Uh oh!

Uh oh!

DaveCTurner commented Dec 23, 2025

Uh oh!

rjernst commented Dec 23, 2025

Uh oh!

rjernst commented Dec 23, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Comments

		.systemProperty("es.insecure_network_trace_enabled", "true")
		.setting("logger.org.apache.http.headers", "TRACE")

Conversation

rjernst commented Dec 9, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

elasticsearchmachine commented Dec 9, 2025

Uh oh!

DaveCTurner left a comment

Choose a reason for hiding this comment

Uh oh!

DaveCTurner commented Dec 9, 2025

Uh oh!

DaveCTurner commented Dec 9, 2025

Uh oh!

DaveCTurner Dec 9, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

DaveCTurner commented Dec 23, 2025

Uh oh!

rjernst commented Dec 23, 2025

Uh oh!

rjernst commented Dec 23, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Comments

rjernst commented Dec 9, 2025 •

edited

Loading