CHANGELOG.md

   1 # Changelog
   2
   3 All notable changes to this project will be documented in this file.
   4
   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).
   7
   8 ## [Unreleased]
   9
  10 ### Changed
  11
  12 - Rename worker choice strategy options `choiceRetries` to `retries`.
  13
  14 ## [2.6.36] - 2023-08-27
  15
  16 ### Fixed
  17
  18 - Fix pool `execute()` arguments check.
  19
  20 ### Changed
  21
  22 - Make continuous tasks stealing algorithm less aggressive.
  23 - Fine tune tasks stealing algorithm under back pressure.
  24
  25 ## [2.6.35] - 2023-08-25
  26
  27 ### Fixed
  28
  29 - Don't account worker usage statistics for tasks that have failed.
  30 - Fix pool information runtime and wait time median computation.
  31
  32 ### Changed
  33
  34 - Update simple moving average implementation to use a circular buffer.
  35 - Update simple moving median implementation to use a circular buffer.
  36 - Account for stolen tasks in worker usage statistics and pool information.
  37
  38 ### Added
  39
  40 - Continuous tasks stealing algorithm.
  41
  42 ## [2.6.34] - 2023-08-24
  43
  44 ### Fixes
  45
  46 - Avoid cascading tasks stealing under back pressure.
  47
  48 ### Changed
  49
  50 - Add fastpath to queued tasks rescheduling.
  51
  52 ## [2.6.33] - 2023-08-24
  53
  54 ### Fixed
  55
  56 - Fix queued tasks rescheduling.
  57
  58 ### Changed
  59
  60 - Rename tasks queue options `queueMaxSize` to `size`.
  61
  62 ### Added
  63
  64 - Task stealing scheduling algorithm if tasks queueing is enabled.
  65
  66 ## [2.6.32] - 2023-08-23
  67
  68 ### Fixed
  69
  70 - Ensure no task can be executed when the pool is destroyed.
  71
  72 ### Added
  73
  74 - Add `queueMaxSize` option to tasks queue options.
  75 - Add O(1) deque implementation implemented with doubly linked list and use it for tasks queueing.
  76 - Add tasks stealing algorithm when a worker node queue is back pressured if tasks queueing is enabled.
  77
  78 ## [2.6.31] - 2023-08-20
  79
  80 ### Fixed
  81
  82 - Fix worker choice strategy retries mechanism in some edge cases.
  83
  84 ### Changed
  85
  86 - Make orthogonal worker choice strategies tasks distribution and created dynamic worker usage.
  87 - Remove the experimental status of the `LEAST_ELU` worker choice strategy.
  88
  89 ## [2.6.30] - 2023-08-19
  90
  91 ### Fixed
  92
  93 - Ensure pool event `backPressure` is emitted.
  94 - Ensure pool event `full` is emitted only once.
  95 - Ensure worker node cannot be instantiated without proper arguments.
  96
  97 ## [2.6.29] - 2023-08-18
  98
  99 ### Fixed
 100
 101 - Fix race condition between ready and task functions worker message handling at startup.
 102 - Fix duplicate task function worker usage statistics computation per task function.
 103 - Update task function worker usage statistics if and only if there's at least two different task functions.
 104 - Fix race condition at task function worker usage executing task computation leading to negative value.
 105
 106 ### Added
 107
 108 - 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).
 109 - Use back pressure detection in worker choice strategies.
 110 - Add worker choice strategies retries mechanism if no worker is eligible.
 111
 112 ## [2.6.28] - 2023-08-16
 113
 114 ### Fixed
 115
 116 - Ensure pool workers are properly initialized.
 117
 118 ### Added
 119
 120 - HTTP server pool examples: express-cluster, express-hybrid.
 121
 122 ### Changed
 123
 124 - Remove now useless branching in worker hot code path.
 125
 126 ## [2.6.27] - 2023-08-15
 127
 128 ### Fixed
 129
 130 - Add `KillHandler` type definition to exported types.
 131
 132 ### Added
 133
 134 - Add `destroy` event to pool API.
 135
 136 ## [2.6.26] - 2023-08-15
 137
 138 ### Added
 139
 140 - Add kill handler to worker options allowing to execute custom code when worker is killed.
 141 - Add `listTaskFunctions()` method to pool API.
 142 - SMTP server pool example: nodemailer.
 143
 144 ## [2.6.25] - 2023-08-13
 145
 146 ### Added
 147
 148 - HTTP server pool examples: fastify-cluster, fastify-hybrid.
 149 - WebSocket server pool examples: ws-cluster, ws-hybrid.
 150
 151 ## [2.6.24] - 2023-08-12
 152
 153 ### Added
 154
 155 - Add array of transferable objects to the `execute()` method arguments.
 156 - WebSocket server pool examples: ws-worker_threads.
 157
 158 ## [2.6.23] - 2023-08-11
 159
 160 ### Fixed
 161
 162 - 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.
 163
 164 ### Added
 165
 166 - HTTP client pool examples: fetch, node-fetch and axios with multiple task functions.
 167 - HTTP server pool examples: express-worker_threads, fastify-worker_threads.
 168
 169 ## [2.6.22] - 2023-08-10
 170
 171 ### Fixed
 172
 173 - Add missing `types` field to package.json `exports`.
 174
 175 ### Changed
 176
 177 - Structure markdown documentation (PR #811).
 178
 179 ## [2.6.21] - 2023-08-03
 180
 181 ### Changed
 182
 183 - Improve code documentation.
 184 - Code refactoring and cleanup for better maintainability and readability.
 185
 186 ## [2.6.20] - 2023-07-21
 187
 188 ### Fixed
 189
 190 - Fix queued tasks redistribution on error task execution starvation.
 191 - Ensure tasks queueing per worker condition is untangled from the pool busyness semantic.
 192
 193 ### Changed
 194
 195 - Drastically reduce lookups by worker in the worker nodes.
 196
 197 ## [2.6.19] - 2023-07-20
 198
 199 ### Added
 200
 201 - Dedicated internal communication channel for worker_threads pools.
 202
 203 ## [2.6.18] - 2023-07-19
 204
 205 ### Changed
 206
 207 - Code refactoring and cleanup for better maintainability and readability. Bundle size is a bit smaller.
 208
 209 ## [2.6.17] - 2023-07-16
 210
 211 ### Added
 212
 213 - Add `listTaskFunctions()` method to worker API.
 214
 215 ## [2.6.16] - 2023-07-12
 216
 217 ### Fixed
 218
 219 - Fix pool startup detection.
 220 - Fix worker task functions handling.
 221
 222 ## [2.6.15] - 2023-07-11
 223
 224 ### Added
 225
 226 - Take into account worker node readiness in worker choice strategies.
 227
 228 ## [2.6.14] - 2023-07-10
 229
 230 ### Fixed
 231
 232 - Fix task function statistics tracking.
 233
 234 ## [2.6.13] - 2023-07-10
 235
 236 ### Added
 237
 238 - Add per task function statistics tracking.
 239 - Add public methods to manipulate the worker task functions at runtime.
 240
 241 ## [2.6.12] - 2023-07-09
 242
 243 ### Fixed
 244
 245 - Workaround import issue with `node:os` module in node 16.x.x.
 246
 247 ## [2.6.11] - 2023-07-09
 248
 249 ### Fixed
 250
 251 - Fix pool readiness semantic.
 252
 253 ## [2.6.10] - 2023-07-08
 254
 255 ### Fixed
 256
 257 - Ensure workers are not recreated on error at pool startup.
 258
 259 ### Added
 260
 261 - Add `ready` and `strategy` fields to pool information.
 262 - Add pool event `ready` to notify when the number of workers created in the pool has reached the maximum size expected and are ready.
 263 - Add dynamic pool sizing checks.
 264
 265 ## [2.6.9] - 2023-07-07
 266
 267 ### Fixed
 268
 269 - Recreate the right worker type on uncaught exception.
 270
 271 ### Added
 272
 273 - Add minimum and maximum to internal measurement statistics.
 274 - Add `runTime` and `waitTime` to pool information.
 275 - Check worker inactive time only on dynamic worker.
 276
 277 ## [2.6.8] - 2023-07-03
 278
 279 ### Fixed
 280
 281 - Brown paper bag release to fix version handling in pool information.
 282
 283 ## [2.6.7] - 2023-07-03
 284
 285 ### Fixed
 286
 287 - Ensure worker queued tasks at error are reassigned to other pool workers.
 288
 289 ### Added
 290
 291 - Add pool `utilization` ratio to pool information.
 292 - Add `version` to pool information.
 293 - Add worker information to worker nodes.
 294
 295 ## [2.6.6] - 2023-07-01
 296
 297 ### Added
 298
 299 - Add safe helper `availableParallelism()` to help sizing the pool.
 300
 301 ### Fixed
 302
 303 - Ensure message handler is only registered in worker.
 304
 305 ## [2.6.5] - 2023-06-27
 306
 307 ### Known issues
 308
 309 - Cluster pools tasks execution are not working by using ESM files extension: https://github.com/poolifier/poolifier/issues/782
 310
 311 ### Fixed
 312
 313 - Artificial version bump to 2.6.5 to workaround publication issue.
 314 - Ensure cluster pool `destroy()` gracefully shutdowns worker's server.
 315 - Ensure pool event is emitted before task error promise rejection.
 316 - Fix queued tasks count computation.
 317
 318 ### Removed
 319
 320 - Remove unneeded worker_threads worker `MessageChannel` internal usage for IPC.
 321
 322 ## [2.6.4] - 2023-06-27
 323
 324 ### Known issues
 325
 326 - Cluster pools tasks execution are not working by using ESM files extension: https://github.com/poolifier/poolifier/issues/782
 327
 328 ### Fixed
 329
 330 - Ensure cluster pool `destroy()` gracefully shutdowns worker's server.
 331 - Ensure pool event is emitted before task error promise rejection.
 332 - Fix queued tasks count computation.
 333
 334 ### Removed
 335
 336 - Remove unneeded worker_threads worker `MessageChannel` internal usage for IPC.
 337
 338 ## [2.6.3] - 2023-06-19
 339
 340 ### Fixed
 341
 342 - Ensure no tasks are queued when trying to soft kill a dynamic worker.
 343 - Update strategies internals after statistics computation.
 344
 345 ### Changed
 346
 347 - Optimize O(1) queue implementation.
 348
 349 ## [2.6.2] - 2023-06-12
 350
 351 ### Fixed
 352
 353 - Fix new worker use after creation in dynamic pool given the current worker choice strategy.
 354
 355 ## [2.6.1] - 2023-06-10
 356
 357 ### Added
 358
 359 - Add worker choice strategy documentation: [README.md](./docs/worker-choice-strategies.md).
 360
 361 ### Fixed
 362
 363 - Fix average statistics computation: ensure failed tasks are not accounted.
 364
 365 ## [2.6.0] - 2023-06-09
 366
 367 ### Added
 368
 369 - Add `LEAST_ELU` worker choice strategy (experimental).
 370 - Add tasks ELU instead of runtime support to `FAIR_SHARE` worker choice strategy.
 371
 372 ### Changed
 373
 374 - Refactor pool worker node usage internals.
 375 - Breaking change: refactor worker choice strategy statistics requirements: the syntax of the worker choice strategy options has changed.
 376 - Breaking change: pool information `info` property object fields have been renamed.
 377
 378 ### Fixed
 379
 380 - Fix wait time accounting.
 381 - Ensure worker choice strategy `LEAST_BUSY` accounts also tasks wait time.
 382 - Ensure worker choice strategy `LEAST_USED` accounts also queued tasks.
 383
 384 ## [2.5.4] - 2023-06-07
 385
 386 ### Added
 387
 388 - Add Event Loop Utilization (ELU) statistics to worker tasks usage.
 389
 390 ### Changed
 391
 392 - Compute statistics at the worker level only if needed.
 393 - Add `worker_threads` options to thread pool options.
 394
 395 ### Fixed
 396
 397 - Make the `LEAST_BUSY` strategy only relies on task runtime.
 398
 399 ## [2.5.3] - 2023-06-04
 400
 401 ### Changed
 402
 403 - Refine pool information content.
 404 - Limit pool internals public exposure.
 405
 406 ## [2.5.2] - 2023-06-02
 407
 408 ### Added
 409
 410 - Add `taskError` pool event for task execution error.
 411 - Add pool information `info` property to pool.
 412 - Emit pool information on `busy` and `full` pool events.
 413
 414 ## [2.5.1] - 2023-06-01
 415
 416 ### Added
 417
 418 - Add pool option `restartWorkerOnError` to restart worker on uncaught error. Default to `true`.
 419 - Add `error` pool event for uncaught worker error.
 420
 421 ## [2.5.0] - 2023-05-31
 422
 423 ### Added
 424
 425 - Switch pool event emitter to `EventEmitterAsyncResource`.
 426 - Add tasks wait time accounting in per worker tasks usage.
 427 - Add interleaved weighted round robin `INTERLEAVED_WEIGHTED_ROUND_ROBIN` worker choice strategy (experimental).
 428
 429 ### Changed
 430
 431 - Renamed worker choice strategy `LESS_BUSY` to `LEAST_BUSY` and `LESS_USED` to `LEAST_USED`.
 432
 433 ## [2.4.14] - 2023-05-09
 434
 435 ### Fixed
 436
 437 - Ensure no undefined task runtime can land in the tasks history.
 438 - Fix median computation implementation once again.
 439
 440 ### Added
 441
 442 - Unit tests for median and queue implementations.
 443
 444 ## [2.4.13] - 2023-05-08
 445
 446 ### Fixed
 447
 448 - Fix worker choice strategy options validation.
 449 - Fix fair share worker choice strategy internals update: ensure virtual task end timestamp is computed at task submission.
 450
 451 ## [2.4.12] - 2023-05-06
 452
 453 ### Added
 454
 455 - Support multiple task functions per worker.
 456 - Add custom worker weights support to worker choice strategies options.
 457
 458 ### Changed
 459
 460 - Use O(1) queue implementation for tasks queueing.
 461
 462 ### Fixed
 463
 464 - Fix median computation implementation.
 465 - Fix fair share worker choice strategy internals update.
 466
 467 ## [2.4.11] - 2023-04-23
 468
 469 ### Changed
 470
 471 - Optimize free worker finding in worker choice strategies.
 472
 473 ## [2.4.10] - 2023-04-15
 474
 475 ### Fixed
 476
 477 - Fix typescript type definition for task function: ensure the input data is optional.
 478 - Fix typescript type definition for pool execute(): ensure the input data is optional.
 479
 480 ## [2.4.9] - 2023-04-15
 481
 482 ### Added
 483
 484 - Add tasks queue enablement runtime setter to pool.
 485 - Add tasks queue options runtime setter to pool.
 486 - Add worker choice strategy options runtime setter to pool.
 487
 488 ### Changed
 489
 490 - Remove the tasks queuing experimental status.
 491
 492 ### Fixed
 493
 494 - Fix task function type definition and validation.
 495 - Fix worker choice strategy options handling.
 496
 497 ## [2.4.8] - 2023-04-12
 498
 499 ### Fixed
 500
 501 - Fix message between main worker and worker type definition for tasks.
 502 - Fix code documentation.
 503
 504 ## [2.4.7] - 2023-04-11
 505
 506 ### Added
 507
 508 - Add worker tasks queue options to pool options.
 509
 510 ### Fixed
 511
 512 - Fix missing documentation.
 513
 514 ## [2.4.6] - 2023-04-10
 515
 516 ### Fixed
 517
 518 - Ensure one task at a time is executed per worker with tasks queueing enabled.
 519 - Properly count worker executing tasks with tasks queueing enabled.
 520
 521 ## [2.4.5] - 2023-04-09
 522
 523 ### Added
 524
 525 - Use monotonic high resolution timer for worker tasks runtime.
 526 - Add worker tasks median runtime to statistics.
 527 - Add worker tasks queue (experimental).
 528
 529 ## [2.4.4] - 2023-04-07
 530
 531 ### Added
 532
 533 - Add `PoolEvents` enumeration and `PoolEvent` type.
 534
 535 ### Fixed
 536
 537 - Destroy worker only on alive check.
 538
 539 ## [2.4.3] - 2023-04-07
 540
 541 ### Fixed
 542
 543 - Fix typedoc generation with inheritance.
 544
 545 ## [2.4.2] - 2023-04-06
 546
 547 ### Added
 548
 549 - Add `full` event to dynamic pool.
 550 - Keep worker choice strategy in memory for conditional reuse.
 551
 552 ### Fixed
 553
 554 - Fix possible negative worker key at worker removal in worker choice strategies.
 555
 556 ## [2.4.1] - 2023-04-05
 557
 558 ### Changed
 559
 560 - Optimize worker choice strategy for dynamic pool.
 561
 562 ### Fixed
 563
 564 - Ensure dynamic pool does not alter worker choice strategy expected behavior.
 565
 566 ## [2.4.0] - 2023-04-04
 567
 568 ### Added
 569
 570 - Add `LESS_BUSY` worker choice strategy.
 571
 572 ### Changed
 573
 574 - Optimize worker storage in pool.
 575 - Optimize worker alive status check.
 576 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 577 - Optimize `LESS_USED` worker choice strategy.
 578 - Update benchmarks versus external threads pools.
 579 - Optimize tasks usage statistics requirements for worker choice strategy.
 580
 581 ### Fixed
 582
 583 - Ensure trimmable characters are checked at pool initialization.
 584 - Fix message id integer overflow.
 585 - Fix pool worker removal in worker choice strategy internals.
 586 - Fix package publication with pnpm.
 587
 588 ## [2.4.0-3] - 2023-04-04
 589
 590 ### Added
 591
 592 - Add `LESS_BUSY` worker choice strategy.
 593
 594 ### Changed
 595
 596 - Optimize worker storage in pool.
 597 - Optimize worker alive status check.
 598 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 599 - Optimize `LESS_USED` worker choice strategy.
 600 - Update benchmarks versus external threads pools.
 601
 602 ### Fixed
 603
 604 - Ensure trimmable characters are checked at pool initialization.
 605 - Fix message id integer overflow.
 606 - Fix pool worker removal in worker choice strategy internals.
 607 - Fix package publication with pnpm.
 608
 609 ## [2.4.0-2] - 2023-04-03
 610
 611 ### Added
 612
 613 - Add `LESS_BUSY` worker choice strategy.
 614
 615 ### Changed
 616
 617 - Optimize worker storage in pool.
 618 - Optimize worker alive status check.
 619 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 620 - Optimize `LESS_USED` worker choice strategy.
 621
 622 ### Fixed
 623
 624 - Ensure trimmable characters are checked at pool initialization.
 625 - Fix message id integer overflow.
 626 - Fix pool worker removal in worker choice strategy internals.
 627 - Fix package publication with pnpm.
 628
 629 ## [2.4.0-1] - 2023-04-03
 630
 631 ### Added
 632
 633 - Add `LESS_BUSY` worker choice strategy.
 634
 635 ### Changed
 636
 637 - Optimize worker storage in pool.
 638 - Optimize worker alive status check.
 639 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 640 - Optimize `LESS_USED` worker choice strategy.
 641
 642 ### Fixed
 643
 644 - Ensure trimmable characters are checked at pool initialization.
 645 - Fix message id integer overflow.
 646 - Fix pool worker removal in worker choice strategy internals.
 647
 648 ## [2.4.0-0] - 2023-04-03
 649
 650 ### Added
 651
 652 - Add `LESS_BUSY` worker choice strategy.
 653
 654 ### Changed
 655
 656 - Optimize worker storage in pool.
 657 - Optimize worker alive status check.
 658 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 659 - Optimize `LESS_USED` worker choice strategy.
 660
 661 ### Fixed
 662
 663 - Ensure trimmable characters are checked at pool initialization.
 664 - Fix message id integer overflow.
 665 - Fix pool worker removal in worker choice strategy internals.
 666
 667 ## [2.3.10] - 2023-03-18
 668
 669 ### Fixed
 670
 671 - Fix package.json `exports` syntax for ESM and CommonJS.
 672
 673 ### Changed
 674
 675 - Permit SemVer pre-release publication.
 676
 677 ## [2.3.10-2] - 2023-03-18
 678
 679 ### Fixed
 680
 681 - Fix package.json `exports` syntax for ESM and CommonJS.
 682
 683 ## [2.3.10-1] - 2023-03-18
 684
 685 ### Changed
 686
 687 - Permit SemVer pre-release publication.
 688
 689 ## [2.3.10-0] - 2023-03-18
 690
 691 ### Fixed
 692
 693 - Fix package.json `exports` syntax for ESM and CommonJS.
 694
 695 ## [2.3.9] - 2023-03-18
 696
 697 ### Changed
 698
 699 - Introduce ESM module support along with CommonJS one.
 700
 701 ### Fixed
 702
 703 - Fix brown paper bag bug referencing the same object literal.
 704
 705 ## [2.3.8] - 2023-03-18
 706
 707 ### Changed
 708
 709 - Switch internal benchmarking code to benny.
 710 - Switch to TypeScript 5.x.x.
 711 - Switch rollup bundler plugins to core ones.
 712 - Switch to TSDoc syntax.
 713 - Enforce conventional commits.
 714
 715 ### Fixed
 716
 717 - Fix random integer generator.
 718 - Fix worker choice strategy pool type identification at initialization.
 719
 720 ## [2.3.7] - 2022-10-23
 721
 722 ### Changed
 723
 724 - Switch to open collective FOSS project funding platform.
 725 - Switch to ts-standard linter configuration on TypeScript code.
 726
 727 ### Fixed
 728
 729 - Fixed missing async on pool execute method.
 730 - Fixed typing in TypeScript example.
 731 - Fixed types in unit tests.
 732
 733 ## [2.3.6] - 2022-10-22
 734
 735 ### Changed
 736
 737 - Cleanup pool attributes and methods.
 738 - Refine error types thrown.
 739
 740 ### Fixed
 741
 742 - Fix continuous integration build on windows.
 743 - Fix code coverage reporting by using c8 instead of nyc.
 744
 745 ## [2.3.5] - 2022-10-21
 746
 747 ### Changed
 748
 749 - Improve benchmarks: add IO intensive task workload, add task size option, integrate code into linter.
 750 - Optimize tasks usage lookup implementation.
 751
 752 ### Fixed
 753
 754 - Fix missed pool event emitter type export.
 755 - Fix typedoc documentation generation.
 756
 757 ## [2.3.4] - 2022-10-17
 758
 759 ### Added
 760
 761 - Fully automate release process with release-it.
 762
 763 ### Changed
 764
 765 - Optimize fair share task scheduling algorithm implementation.
 766 - Update benchmarks versus external pools results with latest version.
 767
 768 ## [2.3.3] - 2022-10-15
 769
 770 ### Added
 771
 772 - Add support for [cluster settings](https://nodejs.org/api/cluster.html#cluster_cluster_settings) in cluster pool options.
 773
 774 ## [2.3.2] - 2022-10-14
 775
 776 ### Changed
 777
 778 - Optimize fair share worker selection strategy implementation.
 779
 780 ### Fixed
 781
 782 - Fix WRR worker selection strategy: ensure the condition triggering the round robin can be fulfilled.
 783
 784 ## [2.3.1] - 2022-10-13
 785
 786 ### Added
 787
 788 - Pool worker choice strategies:
 789   - `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN` strategy based on weighted round robin scheduling algorithm using tasks execution time for now.
 790   - `WorkerChoiceStrategies.FAIR_SHARE` strategy based on fair share scheduling algorithm using tasks execution time for now.
 791
 792 ## [2.2.2] - 2022-10-09
 793
 794 ### Fixed
 795
 796 - Fixed `README.md` file.
 797
 798 ## [2.2.1] - 2022-10-08
 799
 800 ### Added
 801
 802 - Dynamic worker choice strategy change at runtime.
 803
 804 ## [2.2.0] - 2022-01-05
 805
 806 ### Breaking Changes
 807
 808 - Support only Node.js version 16.x.x for cluster pool: upstream cluster API have changed on that version.
 809
 810 ## [2.1.0] - 2021-08-29
 811
 812 ### Added
 813
 814 - Add an optional pool option `messageHandler` to `PoolOptions<Worker>` for registering a message handler callback on each worker.
 815
 816 ### Breaking Changes
 817
 818 - `AbstractWorker` class `maxInactiveTime`, `killBehavior` and `async` attributes have been removed in favour of the same ones in the worker options `opts` public attribute.
 819 - `AbstractWorker` class `lastTask` attribute have been renamed to `lastTaskTimestamp`.
 820 - `AbstractWorker` class `interval` attribute have been renamed to `aliveInterval`.
 821 - `AbstractWorker` class cannot be instantiated without specifying the `mainWorker` argument referencing the main worker.
 822
 823 ## [2.0.2] - 2021-05-12
 824
 825 ### Bug fixes
 826
 827 - Fix `busy` event emission on fixed pool type
 828
 829 ## [2.0.1] - 2021-03-16
 830
 831 ### Bug fixes
 832
 833 - Check if pool options are properly set.
 834 - `busy` event is emitted on all pool types.
 835
 836 ## [2.0.0] - 2021-03-01
 837
 838 ### Bug fixes
 839
 840 - Now a thread/process by default is not deleted when the task submitted take more time than maxInactiveTime configured (issue #70).
 841
 842 ### Breaking Changes
 843
 844 - `FullPool` event is now renamed to `busy`.
 845 - `maxInactiveTime` on `ThreadWorker` default behavior is now changed, if you want to keep the old behavior set `killBehavior` to `KillBehaviors.HARD`.
 846   _Find more details on our JSDoc._
 847
 848 - `maxTasks` option on `FixedThreadPool` and `DynamicThreadPool` is now removed since is no more needed.
 849
 850 - We changed some internal structures, but you shouldn't be too affected by them as these are internal changes.
 851
 852 ### Pool options types declaration merge
 853
 854 `FixedThreadPoolOptions` and `DynamicThreadPoolOptions` type declarations have been merged to `PoolOptions<Worker>`.
 855
 856 #### New `export` strategy
 857
 858 ```js
 859 // Before
 860 const DynamicThreadPool = require('poolifier/lib/dynamic')
 861 // After
 862 const { DynamicThreadPool } = require('poolifier/lib/dynamic')
 863 ```
 864
 865 But you should always prefer just using
 866
 867 ```js
 868 const { DynamicThreadPool } = require('poolifier')
 869 ```
 870
 871 #### New type definitions for input data and response
 872
 873 For cluster worker and worker-thread pools, you can now only send and receive structured-cloneable data.
 874 _This is not a limitation by poolifier but Node.js._
 875
 876 #### Public property replacements
 877
 878 `numWorkers` property is now `numberOfWorkers`
 879
 880 #### Internal (protected) properties and methods renaming
 881
 882 These properties are not intended for end users
 883
 884 - `id` => `nextMessageId`
 885
 886 These methods are not intended for end users
 887
 888 - `_chooseWorker` => `chooseWorker`
 889 - `_newWorker` => `createWorker`
 890 - `_execute` => `internalExecute`
 891 - `_chooseWorker` => `chooseWorker`
 892 - `_checkAlive` => `checkAlive`
 893 - `_run` => `run`
 894 - `_runAsync` => `runAsync`
 895
 896 ## [1.1.0] - 2020-05-21
 897
 898 ### Added
 899
 900 - ThreadWorker support async functions as option
 901 - Various external library patches
 902
 903 ## [1.0.0] - 2020-01-24
 904
 905 ### Added
 906
 907 - FixedThreadPool implementation
 908 - DynamicThreadPool implementation
 909 - WorkerThread implementation to improve developer experience