3 All notable changes to this project will be documented in this file.
5 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
6 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
12 - Convert pool event emitter to event emitter async resource.
14 ## [2.7.2] - 2023-09-23
18 - Add source maps to npm package to ease debugging.
22 - Continuous benchmarking versus other worker pools: [https://poolifier.github.io/benchmark](https://poolifier.github.io/benchmark).
24 ## [2.7.1] - 2023-09-20
28 - Ensure worker message listener used one time are removed after usage.
30 ## [2.7.0] - 2023-09-19
34 - Fix task stealing related tasks queue options handling at runtime.
38 - Rename `listTaskFunctions()` to `listTaskFunctionNames()` in pool and worker API.
42 - Add `hasTaskFunction()`, `addTaskFunction()`, `removeTaskFunction()`, `setDefaultTaskFunction()` methods to pool API: [PR #1148](https://github.com/poolifier/poolifier/pull/1148).
43 - Stricter worker constructor arguments validation.
45 ## [2.6.45] - 2023-09-17
49 - Disable publication on GitHub packages registry on release until authentication issue is fixed.
53 - Add `startWorkers` to pool options to whether start the minimum number of workers at pool initialization or not.
54 - Add `start()` method to pool API to start the minimum number of workers.
55 - Add `taskStealing` and `tasksStealingOnPressure` to tasks queue options to whether enable task stealing or not and whether enable tasks stealing on back pressure or not.
56 - Continuous internal benchmarking: [https://poolifier.github.io/benchmark-results/dev/bench](https://poolifier.github.io/benchmark-results/dev/bench).
58 ## [2.6.44] - 2023-09-08
62 - Use a dedicated PAT to publish on GitHub packages registry.
66 - Publish on GitHub packages registry on release.
70 - Switch from rome to biome: [PR #1128](https://github.com/poolifier/poolifier/pull/1128).
72 ## [2.6.43] - 2023-09-08
76 - Publish on GitHub packages registry on release.
80 - Switch from rome to biome: [PR #1128](https://github.com/poolifier/poolifier/pull/1128).
82 ## [2.6.42] - 2023-09-06
86 - Optimize hot code paths implementation: avoid unnecessary branching, add and use optimized helpers (min, max), use reduce() array helper, ...
88 ## [2.6.41] - 2023-09-03
92 - Optimize worker choice strategies implementation.
94 ## [2.6.40] - 2023-09-01
98 - Do not pre-choose in WRR worker choice strategy to avoid bias.
99 - Avoid array out of bound in worker choice strategies after worker node removal.
101 ## [2.6.39] - 2023-08-30
105 - Fix race condition in worker choice strategies at worker node info querying while not yet initialized.
107 ## [2.6.38] - 2023-08-30
111 - Bundle typescript types declaration into one file.
115 - Improve interleaved weighted round robin worker choice strategy implementation.
117 ## [2.6.37] - 2023-08-28
121 - Ensure unused worker usage statistics are deleted at runtime.
125 - Rename worker choice strategy options `choiceRetries` to `retries`.
126 - Avoid unnecessary branching in worker choice strategies.
128 ## [2.6.36] - 2023-08-27
132 - Fix pool `execute()` arguments check.
136 - Make continuous tasks stealing algorithm less aggressive.
137 - Fine tune tasks stealing algorithm under back pressure.
139 ## [2.6.35] - 2023-08-25
143 - Don't account worker usage statistics for tasks that have failed.
144 - Fix pool information runtime and wait time median computation.
148 - Update simple moving average implementation to use a circular buffer.
149 - Update simple moving median implementation to use a circular buffer.
150 - Account for stolen tasks in worker usage statistics and pool information.
154 - Continuous tasks stealing algorithm.
156 ## [2.6.34] - 2023-08-24
160 - Avoid cascading tasks stealing under back pressure.
164 - Add fastpath to queued tasks rescheduling.
166 ## [2.6.33] - 2023-08-24
170 - Fix queued tasks rescheduling.
174 - Rename tasks queue options `queueMaxSize` to `size`.
178 - Task stealing scheduling algorithm if tasks queueing is enabled.
180 ## [2.6.32] - 2023-08-23
184 - Ensure no task can be executed when the pool is destroyed.
188 - Add `queueMaxSize` option to tasks queue options.
189 - Add O(1) deque implementation implemented with doubly linked list and use it for tasks queueing.
190 - Add tasks stealing algorithm when a worker node queue is back pressured if tasks queueing is enabled.
192 ## [2.6.31] - 2023-08-20
196 - Fix worker choice strategy retries mechanism in some edge cases.
200 - Make orthogonal worker choice strategies tasks distribution and created dynamic worker usage.
201 - Remove the experimental status of the `LEAST_ELU` worker choice strategy.
203 ## [2.6.30] - 2023-08-19
207 - Ensure pool event `backPressure` is emitted.
208 - Ensure pool event `full` is emitted only once.
209 - Ensure worker node cannot be instantiated without proper arguments.
211 ## [2.6.29] - 2023-08-18
215 - Fix race condition between ready and task functions worker message handling at startup.
216 - Fix duplicate task function worker usage statistics computation per task function.
217 - Update task function worker usage statistics if and only if there's at least two different task functions.
218 - Fix race condition at task function worker usage executing task computation leading to negative value.
222 - Add back pressure detection on the worker node queue. Event `backPressure` is emitted when all worker node queues are full (worker node queue size >= poolMaxSize^2).
223 - Use back pressure detection in worker choice strategies.
224 - Add worker choice strategies retries mechanism if no worker is eligible.
226 ## [2.6.28] - 2023-08-16
230 - Ensure pool workers are properly initialized.
234 - HTTP server pool examples: express-cluster, express-hybrid.
238 - Remove now useless branching in worker hot code path.
240 ## [2.6.27] - 2023-08-15
244 - Add `KillHandler` type definition to exported types.
248 - Add `destroy` event to pool API.
250 ## [2.6.26] - 2023-08-15
254 - Add kill handler to worker options allowing to execute custom code when worker is killed.
255 - Add `listTaskFunctions()` method to pool API.
256 - SMTP client pool example: nodemailer.
258 ## [2.6.25] - 2023-08-13
262 - HTTP server pool examples: fastify-cluster, fastify-hybrid.
263 - WebSocket server pool examples: ws-cluster, ws-hybrid.
265 ## [2.6.24] - 2023-08-12
269 - Add array of transferable objects to the `execute()` method arguments.
270 - WebSocket server pool examples: ws-worker_threads.
272 ## [2.6.23] - 2023-08-11
276 - Fix pool busyness semantic when tasks queueing is enabled: the pool is busy when the number of executing tasks on each worker has reached the maximum tasks concurrency per worker.
280 - HTTP client pool examples: fetch, node-fetch and axios with multiple task functions.
281 - HTTP server pool examples: express-worker_threads, fastify-worker_threads.
283 ## [2.6.22] - 2023-08-10
287 - Add missing `types` field to package.json `exports`.
291 - Structure markdown documentation (PR #811).
293 ## [2.6.21] - 2023-08-03
297 - Improve code documentation.
298 - Code refactoring and cleanup for better maintainability and readability.
300 ## [2.6.20] - 2023-07-21
304 - Fix queued tasks redistribution on error task execution starvation.
305 - Ensure tasks queueing per worker condition is untangled from the pool busyness semantic.
309 - Drastically reduce lookups by worker in the worker nodes.
311 ## [2.6.19] - 2023-07-20
315 - Dedicated internal communication channel for worker_threads pools.
317 ## [2.6.18] - 2023-07-19
321 - Code refactoring and cleanup for better maintainability and readability. Bundle size is a bit smaller.
323 ## [2.6.17] - 2023-07-16
327 - Add `listTaskFunctions()` method to worker API.
329 ## [2.6.16] - 2023-07-12
333 - Fix pool startup detection.
334 - Fix worker task functions handling.
336 ## [2.6.15] - 2023-07-11
340 - Take into account worker node readiness in worker choice strategies.
342 ## [2.6.14] - 2023-07-10
346 - Fix task function statistics tracking.
348 ## [2.6.13] - 2023-07-10
352 - Add per task function statistics tracking.
353 - Add public methods to manipulate the worker task functions at runtime.
355 ## [2.6.12] - 2023-07-09
359 - Workaround import issue with `node:os` module in node 16.x.x.
361 ## [2.6.11] - 2023-07-09
365 - Fix pool readiness semantic.
367 ## [2.6.10] - 2023-07-08
371 - Ensure workers are not recreated on error at pool startup.
375 - Add `ready` and `strategy` fields to pool information.
376 - Add pool event `ready` to notify when the number of workers created in the pool has reached the maximum size expected and are ready.
377 - Add dynamic pool sizing checks.
379 ## [2.6.9] - 2023-07-07
383 - Recreate the right worker type on uncaught exception.
387 - Add minimum and maximum to internal measurement statistics.
388 - Add `runTime` and `waitTime` to pool information.
389 - Check worker inactive time only on dynamic worker.
391 ## [2.6.8] - 2023-07-03
395 - Brown paper bag release to fix version handling in pool information.
397 ## [2.6.7] - 2023-07-03
401 - Ensure worker queued tasks at error are reassigned to other pool workers.
405 - Add pool `utilization` ratio to pool information.
406 - Add `version` to pool information.
407 - Add worker information to worker nodes.
409 ## [2.6.6] - 2023-07-01
413 - Add safe helper `availableParallelism()` to help sizing the pool.
417 - Ensure message handler is only registered in worker.
419 ## [2.6.5] - 2023-06-27
423 - Cluster pools tasks execution are not working by using ESM files extension: https://github.com/poolifier/poolifier/issues/782
427 - Artificial version bump to 2.6.5 to workaround publication issue.
428 - Ensure cluster pool `destroy()` gracefully shutdowns worker's server.
429 - Ensure pool event is emitted before task error promise rejection.
430 - Fix queued tasks count computation.
434 - Remove unneeded worker_threads worker `MessageChannel` internal usage for IPC.
436 ## [2.6.4] - 2023-06-27
440 - Cluster pools tasks execution are not working by using ESM files extension: https://github.com/poolifier/poolifier/issues/782
444 - Ensure cluster pool `destroy()` gracefully shutdowns worker's server.
445 - Ensure pool event is emitted before task error promise rejection.
446 - Fix queued tasks count computation.
450 - Remove unneeded worker_threads worker `MessageChannel` internal usage for IPC.
452 ## [2.6.3] - 2023-06-19
456 - Ensure no tasks are queued when trying to soft kill a dynamic worker.
457 - Update strategies internals after statistics computation.
461 - Optimize O(1) queue implementation.
463 ## [2.6.2] - 2023-06-12
467 - Fix new worker use after creation in dynamic pool given the current worker choice strategy.
469 ## [2.6.1] - 2023-06-10
473 - Add worker choice strategy documentation: [README.md](./docs/worker-choice-strategies.md).
477 - Fix average statistics computation: ensure failed tasks are not accounted.
479 ## [2.6.0] - 2023-06-09
483 - Add `LEAST_ELU` worker choice strategy (experimental).
484 - Add tasks ELU instead of runtime support to `FAIR_SHARE` worker choice strategy.
488 - Refactor pool worker node usage internals.
489 - Breaking change: refactor worker choice strategy statistics requirements: the syntax of the worker choice strategy options has changed.
490 - Breaking change: pool information `info` property object fields have been renamed.
494 - Fix wait time accounting.
495 - Ensure worker choice strategy `LEAST_BUSY` accounts also tasks wait time.
496 - Ensure worker choice strategy `LEAST_USED` accounts also queued tasks.
498 ## [2.5.4] - 2023-06-07
502 - Add Event Loop Utilization (ELU) statistics to worker tasks usage.
506 - Compute statistics at the worker level only if needed.
507 - Add `worker_threads` options to thread pool options.
511 - Make the `LEAST_BUSY` strategy only relies on task runtime.
513 ## [2.5.3] - 2023-06-04
517 - Refine pool information content.
518 - Limit pool internals public exposure.
520 ## [2.5.2] - 2023-06-02
524 - Add `taskError` pool event for task execution error.
525 - Add pool information `info` property to pool.
526 - Emit pool information on `busy` and `full` pool events.
528 ## [2.5.1] - 2023-06-01
532 - Add pool option `restartWorkerOnError` to restart worker on uncaught error. Default to `true`.
533 - Add `error` pool event for uncaught worker error.
535 ## [2.5.0] - 2023-05-31
539 - Switch pool event emitter to `EventEmitterAsyncResource`.
540 - Add tasks wait time accounting in per worker tasks usage.
541 - Add interleaved weighted round robin `INTERLEAVED_WEIGHTED_ROUND_ROBIN` worker choice strategy (experimental).
545 - Renamed worker choice strategy `LESS_BUSY` to `LEAST_BUSY` and `LESS_USED` to `LEAST_USED`.
547 ## [2.4.14] - 2023-05-09
551 - Ensure no undefined task runtime can land in the tasks history.
552 - Fix median computation implementation once again.
556 - Unit tests for median and queue implementations.
558 ## [2.4.13] - 2023-05-08
562 - Fix worker choice strategy options validation.
563 - Fix fair share worker choice strategy internals update: ensure virtual task end timestamp is computed at task submission.
565 ## [2.4.12] - 2023-05-06
569 - Support multiple task functions per worker.
570 - Add custom worker weights support to worker choice strategies options.
574 - Use O(1) queue implementation for tasks queueing.
578 - Fix median computation implementation.
579 - Fix fair share worker choice strategy internals update.
581 ## [2.4.11] - 2023-04-23
585 - Optimize free worker finding in worker choice strategies.
587 ## [2.4.10] - 2023-04-15
591 - Fix typescript type definition for task function: ensure the input data is optional.
592 - Fix typescript type definition for pool execute(): ensure the input data is optional.
594 ## [2.4.9] - 2023-04-15
598 - Add tasks queue enablement runtime setter to pool.
599 - Add tasks queue options runtime setter to pool.
600 - Add worker choice strategy options runtime setter to pool.
604 - Remove the tasks queuing experimental status.
608 - Fix task function type definition and validation.
609 - Fix worker choice strategy options handling.
611 ## [2.4.8] - 2023-04-12
615 - Fix message between main worker and worker type definition for tasks.
616 - Fix code documentation.
618 ## [2.4.7] - 2023-04-11
622 - Add worker tasks queue options to pool options.
626 - Fix missing documentation.
628 ## [2.4.6] - 2023-04-10
632 - Ensure one task at a time is executed per worker with tasks queueing enabled.
633 - Properly count worker executing tasks with tasks queueing enabled.
635 ## [2.4.5] - 2023-04-09
639 - Use monotonic high resolution timer for worker tasks runtime.
640 - Add worker tasks median runtime to statistics.
641 - Add worker tasks queue (experimental).
643 ## [2.4.4] - 2023-04-07
647 - Add `PoolEvents` enumeration and `PoolEvent` type.
651 - Destroy worker only on alive check.
653 ## [2.4.3] - 2023-04-07
657 - Fix typedoc generation with inheritance.
659 ## [2.4.2] - 2023-04-06
663 - Add `full` event to dynamic pool.
664 - Keep worker choice strategy in memory for conditional reuse.
668 - Fix possible negative worker key at worker removal in worker choice strategies.
670 ## [2.4.1] - 2023-04-05
674 - Optimize worker choice strategy for dynamic pool.
678 - Ensure dynamic pool does not alter worker choice strategy expected behavior.
680 ## [2.4.0] - 2023-04-04
684 - Add `LESS_BUSY` worker choice strategy.
688 - Optimize worker storage in pool.
689 - Optimize worker alive status check.
690 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
691 - Optimize `LESS_USED` worker choice strategy.
692 - Update benchmark versus external threads pools.
693 - Optimize tasks usage statistics requirements for worker choice strategy.
697 - Ensure trimmable characters are checked at pool initialization.
698 - Fix message id integer overflow.
699 - Fix pool worker removal in worker choice strategy internals.
700 - Fix package publication with pnpm.
702 ## [2.4.0-3] - 2023-04-04
706 - Add `LESS_BUSY` worker choice strategy.
710 - Optimize worker storage in pool.
711 - Optimize worker alive status check.
712 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
713 - Optimize `LESS_USED` worker choice strategy.
714 - Update benchmark versus external threads pools.
718 - Ensure trimmable characters are checked at pool initialization.
719 - Fix message id integer overflow.
720 - Fix pool worker removal in worker choice strategy internals.
721 - Fix package publication with pnpm.
723 ## [2.4.0-2] - 2023-04-03
727 - Add `LESS_BUSY` worker choice strategy.
731 - Optimize worker storage in pool.
732 - Optimize worker alive status check.
733 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
734 - Optimize `LESS_USED` worker choice strategy.
738 - Ensure trimmable characters are checked at pool initialization.
739 - Fix message id integer overflow.
740 - Fix pool worker removal in worker choice strategy internals.
741 - Fix package publication with pnpm.
743 ## [2.4.0-1] - 2023-04-03
747 - Add `LESS_BUSY` worker choice strategy.
751 - Optimize worker storage in pool.
752 - Optimize worker alive status check.
753 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
754 - Optimize `LESS_USED` worker choice strategy.
758 - Ensure trimmable characters are checked at pool initialization.
759 - Fix message id integer overflow.
760 - Fix pool worker removal in worker choice strategy internals.
762 ## [2.4.0-0] - 2023-04-03
766 - Add `LESS_BUSY` worker choice strategy.
770 - Optimize worker storage in pool.
771 - Optimize worker alive status check.
772 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
773 - Optimize `LESS_USED` worker choice strategy.
777 - Ensure trimmable characters are checked at pool initialization.
778 - Fix message id integer overflow.
779 - Fix pool worker removal in worker choice strategy internals.
781 ## [2.3.10] - 2023-03-18
785 - Fix package.json `exports` syntax for ESM and CommonJS.
789 - Permit SemVer pre-release publication.
791 ## [2.3.10-2] - 2023-03-18
795 - Fix package.json `exports` syntax for ESM and CommonJS.
797 ## [2.3.10-1] - 2023-03-18
801 - Permit SemVer pre-release publication.
803 ## [2.3.10-0] - 2023-03-18
807 - Fix package.json `exports` syntax for ESM and CommonJS.
809 ## [2.3.9] - 2023-03-18
813 - Introduce ESM module support along with CommonJS one.
817 - Fix brown paper bag bug referencing the same object literal.
819 ## [2.3.8] - 2023-03-18
823 - Switch internal benchmarking code to benny.
824 - Switch to TypeScript 5.x.x.
825 - Switch rollup bundler plugins to core ones.
826 - Switch to TSDoc syntax.
827 - Enforce conventional commits.
831 - Fix random integer generator.
832 - Fix worker choice strategy pool type identification at initialization.
834 ## [2.3.7] - 2022-10-23
838 - Switch to open collective FOSS project funding platform.
839 - Switch to ts-standard linter configuration on TypeScript code.
843 - Fixed missing async on pool execute method.
844 - Fixed typing in TypeScript example.
845 - Fixed types in unit tests.
847 ## [2.3.6] - 2022-10-22
851 - Cleanup pool attributes and methods.
852 - Refine error types thrown.
856 - Fix continuous integration build on windows.
857 - Fix code coverage reporting by using c8 instead of nyc.
859 ## [2.3.5] - 2022-10-21
863 - Improve benchmarks: add IO intensive task workload, add task size option, integrate code into linter.
864 - Optimize tasks usage lookup implementation.
868 - Fix missed pool event emitter type export.
869 - Fix typedoc documentation generation.
871 ## [2.3.4] - 2022-10-17
875 - Fully automate release process with release-it.
879 - Optimize fair share task scheduling algorithm implementation.
880 - Update benchmark versus external pools results with latest version.
882 ## [2.3.3] - 2022-10-15
886 - Add support for [cluster settings](https://nodejs.org/api/cluster.html#cluster_cluster_settings) in cluster pool options.
888 ## [2.3.2] - 2022-10-14
892 - Optimize fair share worker selection strategy implementation.
896 - Fix WRR worker selection strategy: ensure the condition triggering the round robin can be fulfilled.
898 ## [2.3.1] - 2022-10-13
902 - Pool worker choice strategies:
903 - `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN` strategy based on weighted round robin scheduling algorithm using tasks execution time for now.
904 - `WorkerChoiceStrategies.FAIR_SHARE` strategy based on fair share scheduling algorithm using tasks execution time for now.
906 ## [2.2.2] - 2022-10-09
910 - Fixed `README.md` file.
912 ## [2.2.1] - 2022-10-08
916 - Dynamic worker choice strategy change at runtime.
918 ## [2.2.0] - 2022-01-05
922 - Support only Node.js version 16.x.x for cluster pool: upstream cluster API have changed on that version.
924 ## [2.1.0] - 2021-08-29
928 - Add an optional pool option `messageHandler` to `PoolOptions<Worker>` for registering a message handler callback on each worker.
932 - `AbstractWorker` class `maxInactiveTime`, `killBehavior` and `async` attributes have been removed in favour of the same ones in the worker options `opts` public attribute.
933 - `AbstractWorker` class `lastTask` attribute have been renamed to `lastTaskTimestamp`.
934 - `AbstractWorker` class `interval` attribute have been renamed to `aliveInterval`.
935 - `AbstractWorker` class cannot be instantiated without specifying the `mainWorker` argument referencing the main worker.
937 ## [2.0.2] - 2021-05-12
941 - Fix `busy` event emission on fixed pool type
943 ## [2.0.1] - 2021-03-16
947 - Check if pool options are properly set.
948 - `busy` event is emitted on all pool types.
950 ## [2.0.0] - 2021-03-01
954 - Now a thread/process by default is not deleted when the task submitted take more time than maxInactiveTime configured (issue #70).
958 - `FullPool` event is now renamed to `busy`.
959 - `maxInactiveTime` on `ThreadWorker` default behavior is now changed, if you want to keep the old behavior set `killBehavior` to `KillBehaviors.HARD`.
960 _Find more details on our JSDoc._
962 - `maxTasks` option on `FixedThreadPool` and `DynamicThreadPool` is now removed since is no more needed.
964 - We changed some internal structures, but you shouldn't be too affected by them as these are internal changes.
966 ### Pool options types declaration merge
968 `FixedThreadPoolOptions` and `DynamicThreadPoolOptions` type declarations have been merged to `PoolOptions<Worker>`.
970 #### New `export` strategy
974 const DynamicThreadPool = require('poolifier/lib/dynamic')
976 const { DynamicThreadPool } = require('poolifier/lib/dynamic')
979 But you should always prefer just using
982 const { DynamicThreadPool } = require('poolifier')
985 #### New type definitions for input data and response
987 For cluster worker and worker-thread pools, you can now only send and receive structured-cloneable data.
988 _This is not a limitation by poolifier but Node.js._
990 #### Public property replacements
992 `numWorkers` property is now `numberOfWorkers`
994 #### Internal (protected) properties and methods renaming
996 These properties are not intended for end users
998 - `id` => `nextMessageId`
1000 These methods are not intended for end users
1002 - `_chooseWorker` => `chooseWorker`
1003 - `_newWorker` => `createWorker`
1004 - `_execute` => `internalExecute`
1005 - `_chooseWorker` => `chooseWorker`
1006 - `_checkAlive` => `checkAlive`
1008 - `_runAsync` => `runAsync`
1010 ## [1.1.0] - 2020-05-21
1014 - ThreadWorker support async functions as option
1015 - Various external library patches
1017 ## [1.0.0] - 2020-01-24
1021 - FixedThreadPool implementation
1022 - DynamicThreadPool implementation
1023 - WorkerThread implementation to improve developer experience