CAMEL-23352: Add syncOptimisticRetry option to Aggregate EIP by code-massel · Pull Request #22769 · apache/camel

code-massel · 2026-04-24T21:36:34Z

When optimisticLocking is enabled, retries are normally scheduled asynchronously on a background ScheduledExecutorService, which switches threads and breaks transactional use cases where the aggregation repository and inbound message store must commit/rollback within a single transaction boundary.

The new syncOptimisticRetry flag (default false) causes the retry delay to execute via Thread.sleep on the calling thread instead, preserving the transaction context. This restores the Camel 2.x behavior for users who need it, without changing the default async behavior.

Description

When optimisticLocking is enabled on the Aggregate EIP, retry failures are scheduled asynchronously on a background ScheduledExecutorService. This thread switch breaks transactional use cases where the aggregation repository and inbound message store must commit/rollback within a single transaction boundary (transaction context is bound to the originating thread).

This PR adds a new syncOptimisticRetry option (default false) to the aggregate EIP. When enabled, the retry delay runs via Thread.sleep on the calling thread instead of scheduling on a background executor, preserving the transaction context. Default is false so existing routes are unaffected.

Target

I checked that the commit is targeting the correct branch (Camel 4 uses the main branch)

Tracking

If this is a large change, bug fix, or code improvement, I checked there is a https://issues.apache.org/jira/browse/CAMEL-23352 filed for the change.

Apache Camel coding standards and style

I checked that each commit in the pull request has a meaningful subject line and body.
I have run mvn clean install -DskipTests locally from root folder and I have committed all auto-generated changes.

github-actions · 2026-04-25T06:55:01Z

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davsclaus · 2026-04-25T08:09:02Z

when you add new options to EIPs you generally need to rebuild the entire code base

	modified:   catalog/camel-catalog/src/generated/resources/org/apache/camel/catalog/models/aggregate.json
	modified:   catalog/camel-catalog/src/generated/resources/org/apache/camel/catalog/schemas/camel-spring.xsd
	modified:   catalog/camel-catalog/src/generated/resources/org/apache/camel/catalog/schemas/camel-xml-io.xsd
	modified:   core/camel-core-model/src/generated/resources/META-INF/org/apache/camel/model/aggregate.json
	modified:   core/camel-xml-io/src/generated/java/org/apache/camel/xml/in/ModelParser.java
	modified:   core/camel-xml-io/src/generated/java/org/apache/camel/xml/out/ModelWriter.java
	modified:   core/camel-yaml-io/src/generated/java/org/apache/camel/yaml/out/ModelWriter.java
	modified:   dsl/camel-yaml-dsl/camel-yaml-dsl-deserializers/src/generated/java/org/apache/camel/dsl/yaml/deserializers/ModelDeserializers.java
	modified:   dsl/camel-yaml-dsl/camel-yaml-dsl/src/generated/resources/schema/camelYamlDsl.json

davsclaus · 2026-04-25T08:09:41Z

for example run from root

mvn clean install -P fastinstall

When optimisticLocking is enabled, retries are normally scheduled asynchronously on a background ScheduledExecutorService, which switches threads and breaks transactional use cases where the aggregation repository and inbound message store must commit/rollback within a single transaction boundary. The new syncOptimisticRetry flag (default false) causes the retry delay to execute via Thread.sleep on the calling thread instead, preserving the transaction context. This restores the Camel 2.x behavior for users who need it, without changing the default async behavior.

gnodet

Review: CAMEL-23352 — Add `syncOptimisticRetry` option to Aggregate EIP

Thank you for this contribution! The use case is well-motivated — async optimistic locking retries breaking transaction context is a real problem, and adding an opt-in synchronous retry is a clean approach. The core implementation logic is correct.

A few items need attention before this can merge.

Blocker: Missing generated files

The PR modifies 4 hand-written files but does not include any regenerated downstream artifacts. CI will fail at the "Fail if there are uncommitted changes" step. Please run:

mvn install -B -pl core/camel-core-model -DskipTests

Then check git status and commit all generated file changes. This will update at minimum:

core/camel-core-model/src/generated/ — JSON model metadata, configurers
dsl/camel-yaml-dsl/ — YAML DSL schema and deserializers

The auto-generated options table in the aggregate EIP docs (aggregate-eip.adoc) will also pick up the new option from the Javadoc after regeneration, so a separate prose change is likely not needed.

Implementation

The core retry logic is sound:

The syncOptimisticRetry branch correctly calls doDelay(attempt) then continues the retry loop on the calling thread.
InterruptedException handling correctly restores the interrupt flag and propagates via exchange.setException().
Default (false) preserves existing async behavior — no regression risk.
The reifier and copy constructor correctly wire the new option.

See inline comments for minor suggestions.

Claude Code on behalf of Guillaume Nodet

Rename syncOptimisticRetry → optimisticLockingSyncRetry for consistency with the existing optimisticLocking option naming. Update Javadoc to note the flag only takes effect when optimisticLocking() is enabled. Add tests for non-zero retry delay and thread interruption scenarios. Regenerate catalog metadata.

…chemas)

code-massel · 2026-05-05T20:18:24Z

Thanks for the review! I've addressed your feedback in the latest push:

Renamed syncOptimisticRetry → optimisticLockingSyncRetry across all files for consistency with the existing optimisticLocking option naming
Updated Javadoc to clarify the flag only takes effect when optimisticLocking() is also enabled
Added two new tests: one verifying synchronous retry with a non-zero delay stays on the calling thread, and one exercising the InterruptedException path when the thread is interrupted mid-retry
Regenerated all downstream artifacts (catalog, YAML DSL, XML IO, XSD schemas)

Let me know if there's anything else to adjust

Croway · 2026-05-06T08:25:56Z

+        sender.start();
+
+        // Let at least one retry attempt happen before interrupting
+        Thread.sleep(100);


Can you use Awaitility instead of this Thread.sleep?

Croway · 2026-05-06T08:30:16Z

There are some uncommitted changes:

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	modified:   catalog/camel-catalog/src/generated/resources/org/apache/camel/catalog/schemas/camel-spring.xsd
	modified:   catalog/camel-catalog/src/generated/resources/org/apache/camel/catalog/schemas/camel-xml-io.xsd
	modified:   dsl/camel-yaml-dsl/camel-yaml-dsl/src/generated/resources/schema/camelYamlDsl-canonical.json
	```

github-actions Bot added the core label Apr 25, 2026

davsclaus force-pushed the CAMEL-23352 branch from edf96bb to c6d2b01 Compare April 25, 2026 10:52

gnodet requested changes Apr 27, 2026

View reviewed changes

marcelatsap added 2 commits May 5, 2026 21:28

CAMEL-23352: Regenerate downstream artifacts (YAML DSL, XML IO, XSD s…

1ffa14c

…chemas)

code-massel requested review from davsclaus and gnodet May 5, 2026 20:19

github-actions Bot added catalog dsl labels May 5, 2026

davsclaus approved these changes May 6, 2026

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Croway reviewed May 6, 2026

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CAMEL-23352: Add syncOptimisticRetry option to Aggregate EIP#22769

CAMEL-23352: Add syncOptimisticRetry option to Aggregate EIP#22769
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code-massel commented Apr 24, 2026 •

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Review: CAMEL-23352 — Add `syncOptimisticRetry` option to Aggregate EIP