Fixes #29255: Remove unused LMAX Disruptor event bus and dependency

[harshach]

Describe your changes:

Fixes #29255

I removed the LMAX Disruptor event bus (EventPubSub) and the com.lmax:disruptor dependency because it is dead code. Its only producer, EventPubSub.publish(ChangeEvent), has had zero callers since the change-event flow moved to the database-backed change_event consumer pattern in #14422 — audit_log is now written by AuditLogConsumer (a Quartz job polling change_event), so the disruptor's attached handlers (AuditLogEventPublisher, EventMonitorPublisher) never fired. This deletes the orphaned plumbing plus its now-unreferenced EventMonitor backends and strips the boot wiring from OpenMetadataApplication.

Type of change:

• Improvement

High-level design:

• The live path — ChangeEventHandler → change_event table → AuditLogConsumer (Quartz) → AuditLogRepository.write() → audit_log — is untouched.
• Deleted EventPubSub, EventPublisher, AbstractEventPublisher, AuditLogEventPublisher, EventMonitorPublisher, and the orphaned EventMonitor / EventMonitorFactory / PrometheusEventMonitor / CloudwatchEventMonitor.
• Kept EventMonitorConfiguration / EventMonitorProvider — still used by the Micrometer HTTP metrics filter and ServicesStatusJobHandler.
• Backward compatibility: the CloudWatch/Prometheus ingestion-pipeline metric push was already non-functional (never fed by the disruptor), so no working behavior is lost. It is recoverable from git history if it needs re-wiring onto the change_event consumer.

Tests:

Unit tests

Removed 3 obsolete tests for the deleted classes (CloudWatchEventMonitorTest, EventMonitorFactoryTest, EventMonitorPublisherTest). No new logic was added — this is a pure dead-code removal.

Backend integration tests

• Not applicable (no API behavior change). Existing AuditLogResourceIT continues to cover the live change_event → audit_log path.

Manual testing performed

1. mvn -pl openmetadata-service test-compile — passes (main + test sources compile clean).
2. mvn -pl openmetadata-service spotless:apply — no formatting changes.
3. Verified repo-wide that EventPubSub.publish has no callers and no remaining lmax/disruptor references.

UI screen recording / screenshots:

Not applicable.

Checklist:

• I have read the CONTRIBUTING document.
• My PR title is Fixes <issue-number>: <short explanation>
• My PR is linked to a GitHub issue via Fixes #29255 above.
• For JSON Schema changes: not applicable (no schema changes).
• For UI changes: not applicable (no UI changes).

Greptile Summary

Removes the LMAX Disruptor-based EventPubSub and all attached plumbing (EventPublisher, AbstractEventPublisher, AuditLogEventPublisher, EventMonitorPublisher, EventMonitor* backends) that have had zero live callers since the change-event flow moved to the database-backed change_event consumer pattern. The live audit-log path (ChangeEventHandler → change_event table → AuditLogConsumer Quartz job → audit_log) is untouched.

• Deletes EventPubSub, the six publisher/monitor classes, and their three unit tests; removes com.lmax:disruptor 3.4.4 from both pom.xml files.
• Strips EventPubSub.start(), registerEventPublisher(), and EventPubSub.shutdown() from OpenMetadataApplication; keeps EventMonitorConfiguration and EventMonitorProvider, which are still consumed by ServicesStatusJobHandler and the Micrometer HTTP-metrics filter.

Confidence Score: 4/5

Safe to merge — purely removes dead code and its dependency; no live event path is touched.

The deletion is well-scoped and the live ChangeEventHandler → change_event → AuditLogConsumer → audit_log path is untouched. The only loose end is the software.amazon.awssdk:cloudwatch Maven artifact, which is now orphaned in openmetadata-service/pom.xml now that CloudwatchEventMonitor is gone — it adds unnecessary compile-time weight but does not break anything at runtime.

openmetadata-service/pom.xml — the CloudWatch AWS SDK dependency block should be removed alongside the deleted monitor class.

Important Files Changed

Filename	Overview
openmetadata-service/pom.xml	Removes the com.lmax:disruptor dependency; the software.amazon.awssdk:cloudwatch dependency is now orphaned and should also be removed.
openmetadata-service/src/main/java/org/openmetadata/service/OpenMetadataApplication.java	Removes EventPubSub.start(), registerEventPublisher(), and EventPubSub.shutdown() boot wiring; live audit-log and event-subscription paths are untouched.
openmetadata-service/src/main/java/org/openmetadata/service/events/EventPubSub.java	Deleted — LMAX Disruptor ring-buffer implementation with zero live callers.
openmetadata-service/src/main/java/org/openmetadata/service/monitoring/CloudwatchEventMonitor.java	Deleted — the sole consumer of the CloudWatch AWS SDK; its removal leaves the cloudwatch Maven artifact orphaned.
pom.xml	Removes com.lmax:disruptor 3.4.4 from the root BOM; no remaining references across the repository.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    subgraph removed["❌ Removed (dead code)"]
        EP["EventPubSub\n(LMAX Disruptor)"]
        ALEP["AuditLogEventPublisher"]
        EMP["EventMonitorPublisher"]
        EM["EventMonitor\n(CloudWatch / Prometheus)"]
        EP --> ALEP
        EP --> EMP
        EMP --> EM
    end

    subgraph live["✅ Live path (unchanged)"]
        CEH["ChangeEventHandler"]
        CE["change_event table"]
        ALC["AuditLogConsumer\n(Quartz job)"]
        AL["audit_log table"]
        CEH --> CE --> ALC --> AL
    end

    style removed fill:#fdd,stroke:#f66
    style live fill:#dfd,stroke:#6a6

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    subgraph removed["❌ Removed (dead code)"]
        EP["EventPubSub\n(LMAX Disruptor)"]
        ALEP["AuditLogEventPublisher"]
        EMP["EventMonitorPublisher"]
        EM["EventMonitor\n(CloudWatch / Prometheus)"]
        EP --> ALEP
        EP --> EMP
        EMP --> EM
    end

    subgraph live["✅ Live path (unchanged)"]
        CEH["ChangeEventHandler"]
        CE["change_event table"]
        ALC["AuditLogConsumer\n(Quartz job)"]
        AL["audit_log table"]
        CEH --> CE --> ALC --> AL
    end

    style removed fill:#fdd,stroke:#f66
    style live fill:#dfd,stroke:#6a6

Loading

Comments Outside Diff (1)

1. openmetadata-service/pom.xml, line 551-557 (link)

   The software.amazon.awssdk:cloudwatch artifact is now orphaned. Its only Java consumer was CloudwatchEventMonitor, which was deleted in this PR. No remaining source file under src/main/java imports any class from software.amazon.awssdk.services.cloudwatch.

   Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

_{Reviews (1): Last reviewed commit: "Fixes #29255: Remove unused LMAX Disrupt..." | Re-trigger Greptile}

[github-actions]

✅ PR checks passed

The linked issue has a description and all required Shipping project fields set. Thanks!

[gitar-bot]

Code Review ✅ Approved

Removes the unused LMAX Disruptor event bus and its associated dependency, effectively cleaning up orphaned code paths. No issues found.

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[sonarqubecloud]

Quality Gate passed for 'open-metadata-ingestion'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

🟡 Playwright Results — all passed (8 flaky)

✅ 4312 passed · ❌ 0 failed · 🟡 8 flaky · ⏭️ 88 skipped

Shard	Passed	Failed	Flaky	Skipped
✅ Shard 1	302	0	0	4
🟡 Shard 2	813	0	2	9
🟡 Shard 3	814	0	2	8
🟡 Shard 4	858	0	1	12
🟡 Shard 5	732	0	1	47
🟡 Shard 6	793	0	2	8

🟡 8 flaky test(s) (passed on retry)

• Features/DataQuality/TestCaseImportExportE2eFlow.spec.ts › Admin: Complete export-import-validate flow (shard 2, 1 retry)
• Features/Glossary/GlossaryTermRelationsGraph.spec.ts › cross-glossary related term appears as a node in the Relations Graph (shard 2, 1 retry)
• Features/SettingsNavigationPage.spec.ts › should save changes and navigate when "Save changes" is clicked in blocker (shard 3, 1 retry)
• Flow/AddRoleAndAssignToUser.spec.ts › Verify assigned role to new user (shard 3, 1 retry)
• Pages/DataContracts.spec.ts › Create Data Contract and validate for SearchIndex (shard 4, 1 retry)
• Pages/ExplorePageRightPanel_KnowledgeCenter.spec.ts › Should remove user owner for knowledgeCenter (shard 5, 1 retry)
• Pages/Lineage/DataAssetLineage.spec.ts › Column lineage for apiEndpoint -> table (shard 6, 1 retry)
• Pages/Lineage/LineageFilters.spec.ts › Verify Impact Analysis service filter selection (shard 6, 1 retry)

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How to debug locally

# Download playwright-test-results-<shard> artifact and unzip
npx playwright show-trace path/to/trace.zip    # view trace