TaskExecutor ScheduledExecutorService etc. cleanup by vorburger · Pull Request #19 · enola-dev/be

vorburger · 2025-10-05T00:40:32Z

No description provided.

…no need)

gemini-code-assist · 2025-10-05T00:40:47Z

Summary of Changes

Hello @vorburger, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the TaskExecutor by introducing a crucial time-based eviction mechanism for completed tasks, effectively addressing potential memory leaks. Concurrently, it undertakes a substantial refactoring effort to centralize and standardize the creation and management of ExecutorService and ScheduledExecutorService instances. This involves moving common utilities for virtual threads and robust uncaught exception logging into a new, dedicated dev.enola.common.concurrent package, thereby improving code maintainability, reliability, and ensuring proper resource cleanup.

Highlights

Task Eviction Policy: Implemented a time-based eviction policy for completed tasks within the TaskExecutor to prevent memory leaks, with a default eviction interval of one hour.
Executor Refactoring: Centralized and standardized the creation of ExecutorService and ScheduledExecutorService instances, moving utility methods for virtual threads and robust uncaught exception logging to a new dev.enola.common.concurrent package.
Improved Thread Management: Introduced named virtual threads for scheduled executors and integrated logging for uncaught exceptions in all managed executors, enhancing debuggability and reliability.

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Copilot

Pull Request Overview

This PR refactors the TaskExecutor and related concurrent utilities by extracting common functionality into reusable components and adding automated cleanup capabilities. The changes move away from hardcoded implementations toward a more modular and maintainable concurrent utilities framework.

Extracted LoggingThreadUncaughtExceptionHandler into a standalone utility class with factory method
Created a centralized Executors utility class for creating configured executor services with virtual threads
Added automated cleanup scheduling for completed tasks in TaskExecutor with configurable eviction intervals

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/dev/enola/common/concurrent/LoggingThreadUncaughtExceptionHandler.java	New utility class for handling uncaught exceptions with logging support
src/dev/enola/common/concurrent/Executors.java	New factory class for creating configured executor services with virtual threads
src/dev/enola/be/task/TaskExecutorServices.java	Removed - functionality moved to common utilities
src/dev/enola/be/task/TaskExecutor.java	Updated to use new utilities and added automated cleanup scheduling

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gemini-code-assist

Code Review

This pull request introduces a cleanup mechanism for completed tasks to prevent memory leaks and refactors executor creation into a new common utility class. The changes are a good improvement, but I've identified a critical bug in the task eviction scheduling logic that could cause incorrect behavior. I've also found some opportunities to improve maintainability by removing code duplication and an obsolete comment.

vorburger · 2025-10-05T00:46:54Z

/gemini review

gemini-code-assist

Code Review

This pull request is a good refactoring that moves executor service creation to a common utility package and adds a mechanism to clean up completed tasks, addressing a potential memory leak. The changes are generally well-structured. I have identified two high-severity issues: one in TaskExecutor related to the precision of the cleanup interval, which could prevent cleanup from running periodically for sub-second intervals, and another in the new Executors utility class concerning the use of virtual threads for a ScheduledExecutorService, which is an established anti-pattern. I've included specific code suggestions to address these points.

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Copilot

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

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Copilot

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

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vorburger · 2025-10-05T01:02:26Z

/gemini review

gemini-code-assist

Code Review

This pull request refactors the creation of ExecutorService and ScheduledExecutorService into a new common Executors utility class. It also introduces a mechanism in TaskExecutor to periodically evict completed tasks, preventing a memory leak. The changes are well-structured. My feedback focuses on improving the API of the new Executors utility for better consistency and diagnostics.

vorburger · 2025-10-05T01:08:17Z

/gemini review

Copilot

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

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gemini-code-assist

Code Review

This pull request is a nice cleanup and improvement. It refactors the creation of ExecutorServices into a new common utility class dev.enola.common.concurrent.Executors, which improves code organization and reusability. It also introduces a periodic cleanup of completed tasks in TaskExecutor to prevent potential memory leaks, addressing a previous TODO. My review includes a critical fix for the new Executors class and a suggestion to improve the robustness of the new TaskExecutor constructor.

Copilot

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

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Copilot · 2025-10-05T01:09:42Z

+        cleanupScheduler.close();
        timeoutScheduler.close();
+        executor.close();


The executor services should be shut down in reverse order of dependency to avoid potential issues. Since the executor might have tasks that could be cancelled by the timeout scheduler, consider closing the executor first, then the timeout scheduler, and finally the cleanup scheduler.

Suggested change

cleanupScheduler.close();

timeoutScheduler.close();

executor.close();

executor.close();

timeoutScheduler.close();

cleanupScheduler.close();

Copilot · 2025-10-05T01:09:43Z

+    private void evictCompletedTasks() {
+        tasks.values().removeIf(task -> task.status().isTerminal());
+    }


The evictCompletedTasks method iterates over all tasks to find completed ones. For large task maps, this could be inefficient. Consider maintaining a separate queue of completed tasks or using a time-based eviction strategy that tracks completion timestamps.

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Copilot

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

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Copilot · 2025-10-05T01:12:15Z

+    public TaskExecutor(Duration completedTaskEvictionInterval) {
+        if (completedTaskEvictionInterval == null) {
+            throw new IllegalArgumentException("completedTaskEvictionInterval must not be null");
+        }
+        if (completedTaskEvictionInterval.isNegative() || completedTaskEvictionInterval.isZero()) {
+            throw new IllegalArgumentException("completedTaskEvictionInterval must be positive");
+        }


Consider using Objects.requireNonNull() for the null check on line 47-48 for consistency with the null validation pattern used elsewhere in the codebase.

vorburger added 3 commits October 5, 2025 02:10

fix: Implement periodic cleanup of completed tasks in TaskExecutor

9af6de1

clean: Remove TODO re. virtual threads for ScheduledExecutorService (…

efabdc5

…no need)

fix: Use ScheduledExecutorService with uncaughtExceptionHandler

8cf3967

Copilot AI review requested due to automatic review settings October 5, 2025 00:40

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Comment thread src/dev/enola/be/task/TaskExecutor.java Outdated

Comment thread src/dev/enola/common/concurrent/Executors.java Outdated

Comment thread src/dev/enola/common/concurrent/LoggingThreadUncaughtExceptionHandler.java Outdated

clean: Apply findings from Gemini Code Assist

aa3b62c

gemini-code-assist Bot reviewed Oct 5, 2025

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Comment thread src/dev/enola/be/task/TaskExecutor.java Outdated

Comment thread src/dev/enola/common/concurrent/Executors.java Outdated

fix: Use Millis instead of Seconds in TaskExecutor

f0d4d7a

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Copilot AI review requested due to automatic review settings October 5, 2025 00:50

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Comment thread src/dev/enola/be/task/TaskExecutor.java

Comment thread src/dev/enola/be/task/TaskExecutor.java

Comment thread src/dev/enola/be/task/TaskExecutor.java

fix: Switch order in TaskExecutor.close()

d1705bc

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Comment thread src/dev/enola/be/task/TaskExecutor.java

Comment thread src/dev/enola/be/task/TaskExecutor.java

fix: Use Platform instead of Virtual thread for ScheduledExecutorService

3eaaa7a

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Comment thread src/dev/enola/be/task/TaskExecutor.java Outdated

Comment thread src/dev/enola/common/concurrent/Executors.java Outdated

clean: newVirtualThreadPerTaskExecutor() shorter name

5968af2

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Comment thread src/dev/enola/be/task/TaskExecutor.java

fix: Make TaskExecutor completedTaskEvictionInterval more robust

3f7d00f

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Comment thread src/dev/enola/be/task/TaskExecutor.java

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fix: Executors Thread.ofVirtual() builder gotcha

070dfd4

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Copilot AI review requested due to automatic review settings October 5, 2025 01:11

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vorburger added this pull request to the merge queue Oct 5, 2025

Merged via the queue into enola-dev:main with commit 618b7c7 Oct 5, 2025
1 check passed

vorburger deleted the TaskExecutor-cleanupScheduler branch October 5, 2025 01:15

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