Improve Docker event listener #488
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Hello @MichelFR, 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!
Summary of Changes
Hello team,
Gemini here, providing a summary of this pull request to help everyone quickly understand the changes.
This PR aims to improve the Docker event listener implementation. Specifically, it expands the range of Docker container events that the application listens for and simplifies the way these event handlers are registered in the main application file. The goal is to make the event handling more comprehensive and the code cleaner.
Highlights
- Simplified Event Registration: The repetitive code for registering individual Docker event listeners in
src/index.tshas been replaced with a more concise and maintainable approach using a map and a loop.
Changelog
- src/index.ts
- Replaced multiple explicit
DockerService.events.on(...)calls (lines 212-273) with a single loop iterating over a neweventMap(lines 210-232) to register handlers for various Docker events. - Added an
eventMap(lines 211-223) to map Docker event actions to human-readable log names.
- Replaced multiple explicit
- src/services/DockerService.ts
- Added a
SetcalledhandledActions(lines 34-46) listing all the Docker container event actions that should be processed. - Modified the event processing logic (lines 62-67) to check if an incoming Docker event's action is present in the
handledActionsset before emitting the corresponding internal event, replacing the previousswitchstatement that only handled a few actions. - Corrected a variable name in an error log message within the
data.on('error', ...)handler (line 75).
- Added a
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Events flow like streams,
Docker signals change within,
Code listens, reacts.
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Code Review
This pull request significantly improves the Docker event listening mechanism. The refactoring in src/index.ts to use an eventMap for handler registration makes the code more concise and easier to maintain. The expansion of handled event types in DockerService.ts and the use of a Set for handledActions are also positive changes.
A critical bug fix in DockerService.ts regarding error variable logging has also been addressed, which enhances the reliability of error reporting.
Overall, these are valuable improvements. I have one suggestion regarding the synchronization of event definitions between index.ts and DockerService.ts to further improve maintainability and prevent potential future issues.
Summary of Findings
- Error Logging Correction in DockerService: A high-severity issue in
src/services/DockerService.tswhere an incorrect variable (errinstead oferror) was used in an error log message has been fixed. This change ensures accurate reporting of errors from the Docker event stream. - Synchronization of Docker Event Definitions: The list of handled Docker event names is currently defined independently in
src/index.ts(aseventMapkeys) andsrc/services/DockerService.ts(ashandledActions). There's a medium-severity risk that these lists could diverge over time, leading to potential bugs like missed events or unhandled listeners. A suggestion has been made to centralize these definitions using shared constants to improve maintainability and robustness.
Merge Readiness
This pull request introduces excellent improvements to the Docker event listener, enhancing code clarity and maintainability. The fix for the error logging in DockerService.ts is particularly noteworthy.
While the changes are largely positive, I've raised a medium-severity suggestion regarding the synchronization of Docker event definitions between index.ts and DockerService.ts. Addressing this would further strengthen the codebase against future inconsistencies.
I recommend considering this suggestion before merging. As I am an AI, I am not authorized to approve pull requests; please ensure further review and approval from team members.
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| data.on('error', (error: any) => { | ||
| logger.error('Error while listening to docker events:', err); | ||
| logger.error('Error while listening to docker events:', error); |
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It's great to see this line corrected to use the error variable from the data.on('error', (error: any) => { ... }) callback. Previously, it was using err (presumably from the outer DockerService.docker.getEvents({}, (err: any, data: any) => { ... }) scope), which could lead to incorrect or misleading error logs if err was undefined or held an unrelated error object at the time this inner error handler was invoked.
This fix ensures that the specific error related to the event data stream is accurately logged, which is crucial for debugging. Well done on catching and correcting this!
| const eventMap: Record<string, string> = { | ||
| create: 'created', | ||
| start: 'started', | ||
| die: 'died', | ||
| health_status: 'health_status', | ||
| stop: 'stopped', | ||
| destroy: 'destroyed', | ||
| rename: 'renamed', | ||
| update: 'updated', | ||
| pause: 'paused', | ||
| unpause: 'unpaused', | ||
| restart: 'restarted', | ||
| }; |
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The new eventMap and the loop for registering handlers greatly simplify the code and reduce boilerplate, which is a fantastic improvement for readability and maintainability!
I've noticed that the keys of this eventMap directly correspond to the handledActions set defined in src/services/DockerService.ts. While they are currently in sync, there's a potential for them to diverge in the future if one is updated and the other is overlooked. This could lead to index.ts attempting to listen for an event that DockerService.ts no longer emits, or DockerService.ts emitting events that index.ts doesn't have a mapping for.
To ensure these definitions remain synchronized and to establish a single source of truth, have you considered defining these Docker event names (and perhaps their corresponding log names) in a shared location? For example:
- Create a new constants file (e.g.,
src/docker-event-definitions.ts). - Define the canonical list of event action strings there, perhaps as a
constarray:// src/docker-event-definitions.ts export const DOCKER_EVENT_ACTIONS = [ 'create', 'start', 'die', 'health_status', 'stop', 'destroy', 'rename', 'update', 'pause', 'unpause', 'restart' ] as const; export type DockerEventAction = typeof DOCKER_EVENT_ACTIONS[number]; export const DOCKER_EVENT_LOG_NAMES: Record<DockerEventAction, string> = { create: 'created', start: 'started', die: 'died', health_status: 'health_status changed', stop: 'stopped', destroy: 'destroyed', rename: 'renamed', update: 'updated', pause: 'paused', unpause: 'unpaused', restart: 'restarted', };
DockerService.tscould then importDOCKER_EVENT_ACTIONSand initialize itshandledActionsset:new Set(DOCKER_EVENT_ACTIONS).- This file (
index.ts) could importDOCKER_EVENT_LOG_NAMESand use it directly as theeventMap.
This approach would make managing the supported Docker events more robust and less prone to inconsistencies. What are your thoughts on this?
Summary
index.tsTesting
npm testhttps://chatgpt.com/codex/tasks/task_e_68402557fb448329a2a0e034a6fed1ab