feat: add commons pool2 instrumentation by YaoYingLong · Pull Request #19091 · open-telemetry/opentelemetry-java-instrumentation

YaoYingLong · 2026-06-28T13:19:54Z

Add support for commons pool2

Copilot

Pull request overview

This PR adds a new instrumentation family for Apache Commons Pool 2, enabling database connection pool metrics for GenericObjectPool and GenericKeyedObjectPool instances. It follows the established pattern of the existing database-pool instrumentations (Apache DBCP, c3p0, Alibaba Druid), providing a standalone library entrypoint (CommonsPool2Telemetry) plus a javaagent module that auto-registers metrics on pool construction and unregisters them on jmxUnregister.

Changes:

Adds library, javaagent, and testing modules under instrumentation/apache-commons-pool2, wiring metrics through DbConnectionPoolMetrics and using an identity-key map for pool lifecycle tracking.
Registers the new Gradle projects, supported-library docs, metadata, and latest-dependency version pin.
Adds FOSSA targets for the new modules (with an incorrect project path).

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
`settings.gradle.kts`	Registers the three new `apache-commons-pool2` Gradle projects
`instrumentation/apache-commons-pool2/library/.../ConnectionPoolMetrics.java`	Core metric registration/callback logic for both pool MXBean types via identity-keyed map
`instrumentation/apache-commons-pool2/library/.../CommonsPool2Telemetry.java`	Public library entrypoint accepting an `Object` pool
`instrumentation/apache-commons-pool2/javaagent/.../BaseGenericObjectPoolInstrumentation.java`	Constructor + `jmxUnregister` advice; derives pool name from JMX `ObjectName` with fallbacks
`instrumentation/apache-commons-pool2/javaagent/.../CommonsPool2Singletons.java`	Holds the `CommonsPool2Telemetry` singleton
`instrumentation/apache-commons-pool2/javaagent/.../CommonsPool2InstrumentationModule.java`	Registers the type instrumentation
`instrumentation/apache-commons-pool2/testing/.../AbstractCommonsPool2InstrumentationTest.java`	Shared tests covering both pool types with JMX enabled/disabled
`instrumentation/apache-commons-pool2/{library,javaagent}/src/test/.../CommonsPool2InstrumentationTest.java`	Library/agent test subclasses
`instrumentation/apache-commons-pool2/*/build.gradle.kts`	Build config, muzzle range, and stable-semconv test tasks
`instrumentation/apache-commons-pool2/metadata.yaml`	Instrumentation metadata and semconv opt-in config
`docs/supported-libraries.md`	Documents the new supported library
`.github/config/latest-dep-versions.json`	Pins latest commons-pool2 version
`.fossa.yml`	Adds FOSSA targets (referencing a non-existent project path)

+      target: ':instrumentation:commons-pool2-2.0:javaagent'
+    - type: gradle
+      path: ./
+      target: ':instrumentation:commons-pool2-2.0:library'


opentelemetry-pr-dashboard · 2026-06-28T13:26:29Z

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laurit · 2026-06-29T14:06:48Z

+  static void registerMetrics(OpenTelemetry openTelemetry, Object pool, String poolName) {
+    if (pool instanceof GenericObjectPoolMXBean) {
+      GenericObjectPoolMXBean objectPool = (GenericObjectPoolMXBean) pool;
+      registerMetrics(


how do you know that this pool is actually used for database connections?

This connection pool has a wide range of use cases and is not limited to database connection scenarios. For example, it can serve as a socket connection pool in Lettuce, Jedis, or Thrift applications, and can also function as other types of object pools. Should we define a separate set of metrics without database-specific semantics, instead of reusing the existing metric names designed for databases?

My understanding is that connection pool metrics can not be reused for other object pools.

laurit · 2026-06-29T16:06:42Z

+
+      String name = objectName == null ? null : objectName.getKeyProperty("name");
+      if (name == null) {
+        name = String.valueOf(System.identityHashCode(pool));


metric attributes should have low cardinality

jaydeluca · 2026-06-30T10:13:33Z

+            .and(takesArgument(1, named("java.lang.String")))
+            .and(takesArgument(2, named("java.lang.String"))),


named() does an exact type-name match and is mainly useful when you want to avoid classloading or reference a type that may not be on the compile classpath. For JDK core types like String, you can use the class literal instead

Suggested change

.and(takesArgument(1, named("java.lang.String")))

.and(takesArgument(2, named("java.lang.String"))),

.and(takesArgument(1, named(String.class)))

.and(takesArgument(2, named(String.class))),

jaydeluca · 2026-06-30T11:45:00Z

+    idleObjectsAttributes = attributes.toBuilder().put(OBJECT_STATE, STATE_IDLE).build();
+  }
+
+  ObservableLongMeasurement objects() {


since these metrics don't follow the semantic conventions, i think we'd need put them behind a feature flag in the java agent instrumentation. Or maybe based on Lauri's comment these all need to be reworked to just focus on database

@laurit @jaydeluca If we only focus on database scenarios such as Jedis and Lettuce, we will have to implement targeted handling for these two libraries. However, there are also non-database use cases. For instance, Thrift relies on commons-pool2 object pools to manage socket connections, where commons-pool2 is used as a standalone dependency instead of being built into Thrift. Such scenarios would not be covered under the database-only approach. Which of the two solutions do you recommend? Should we only instrument database-related components like Jedis and Lettuce, or instrument the entire commons-pool2 module with a feature toggle to enable or disable the capability?

jaydeluca · 2026-06-30T11:47:26Z

 | [Apache CXF JAX-RS](https://cxf.apache.org/)                                                                                                | 3.2+ (not including 4.0+ yet)      | N/A                                                                                                                                                                                                                                                                                                                                                                                     | Provides `http.route` [2], Controller Spans [3]                                                                                                   |
 | [Apache CXF JAX-WS](https://cxf.apache.org/)                                                                                                | 3.0+ (not including 4.0+ yet)      | N/A                                                                                                                                                                                                                                                                                                                                                                                     | Provides `http.route` [2], Controller Spans [3]                                                                                                   |
 | [Apache DBCP](https://commons.apache.org/proper/commons-dbcp/)                                                                              | 2.0+                               | [opentelemetry-apache-dbcp-2.0](../instrumentation/apache-dbcp-2.0/library)                                                                                                                                                                                                                                                                                                             | [Database Pool Metrics]                                                                                                                           |
+| [Apache Commons Pool 2](https://commons.apache.org/proper/commons-pool/)                                                                    | 2.0+                               | [opentelemetry-apache-commons-pool2-2.0](../instrumentation/apache-commons-pool2-2.0/library)                                                                                                                                                                                                                                                                                           | none                                                                                                                                              |


this should be put in alphabetical order

feat: add commons pool2 instrumentation

969a453

Copilot AI review requested due to automatic review settings June 28, 2026 13:19

YaoYingLong requested a review from a team as a code owner June 28, 2026 13:19

Copilot started reviewing on behalf of YaoYingLong June 28, 2026 13:20 View session

opentelemetry-pr-dashboard Bot mentioned this pull request Jun 28, 2026

Pull Request Dashboard #18435

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Copilot AI reviewed Jun 28, 2026

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Comment thread .fossa.yml Outdated

Comment on lines +99 to +102

target: ':instrumentation:commons-pool2-2.0:javaagent'

- type: gradle

path: ./

target: ':instrumentation:commons-pool2-2.0:library'

YaoYingLong added 2 commits June 29, 2026 11:07

fix: fix unsuccessful CI workflow checks

320c1cc

docs: fix Apache Commons Pool 2 library link

516fcaf

laurit reviewed Jun 29, 2026

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YaoYingLong added 3 commits June 30, 2026 11:14

feat: replace commons-pool2 db metrics with object pool metrics

7d22fb4

fix: reserve commons-pool2 pool names only while active

fa7c17a

refactor: optimize poolName logic

c56578c

jaydeluca reviewed Jun 30, 2026

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feat: add commons pool2 instrumentation#19091

feat: add commons pool2 instrumentation#19091
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