fix: readd cpu speed computation but only if necessary
[poolifier.git] / docs / api.md
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1# [API](https://poolifier.github.io/poolifier/)
2
3## Table of contents
4
5- [Pool](#pool)
6 - [`pool = new FixedThreadPool/FixedClusterPool(numberOfThreads/numberOfWorkers, filePath, opts)`](#pool--new-fixedthreadpoolfixedclusterpoolnumberofthreadsnumberofworkers-filepath-opts)
7 - [`pool = new DynamicThreadPool/DynamicClusterPool(min, max, filePath, opts)`](#pool--new-dynamicthreadpooldynamicclusterpoolmin-max-filepath-opts)
7d91a8cd 8 - [`pool.execute(data, name, transferList)`](#poolexecutedata-name-transferlist)
47352846 9 - [`pool.start()`](#poolstart)
a47027a0 10 - [`pool.destroy()`](#pooldestroy)
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11 - [`pool.hasTaskFunction(name)`](#poolhastaskfunctionname)
12 - [`pool.addTaskFunction(name, fn)`](#pooladdtaskfunctionname-fn)
13 - [`pool.removeTaskFunction(name)`](#poolremovetaskfunctionname)
6703b9f4 14 - [`pool.listTaskFunctionNames()`](#poollisttaskfunctionnames)
9eae3c69 15 - [`pool.setDefaultTaskFunction(name)`](#poolsetdefaulttaskfunctionname)
31d71267 16 - [Pool options](#pool-options)
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17- [Worker](#worker)
18 - [`class YourWorker extends ThreadWorker/ClusterWorker`](#class-yourworker-extends-threadworkerclusterworker)
19 - [`YourWorker.hasTaskFunction(name)`](#yourworkerhastaskfunctionname)
20 - [`YourWorker.addTaskFunction(name, fn)`](#yourworkeraddtaskfunctionname-fn)
21 - [`YourWorker.removeTaskFunction(name)`](#yourworkerremovetaskfunctionname)
6703b9f4 22 - [`YourWorker.listTaskFunctionNames()`](#yourworkerlisttaskfunctionnames)
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23 - [`YourWorker.setDefaultTaskFunction(name)`](#yourworkersetdefaulttaskfunctionname)
24
25## Pool
26
27### `pool = new FixedThreadPool/FixedClusterPool(numberOfThreads/numberOfWorkers, filePath, opts)`
28
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29`numberOfThreads/numberOfWorkers` (mandatory) Number of workers for this pool.
30`filePath` (mandatory) Path to a file with a worker implementation.
31`opts` (optional) An object with the pool options properties described below.
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32
33### `pool = new DynamicThreadPool/DynamicClusterPool(min, max, filePath, opts)`
34
8c445a4e 35`min` (mandatory) Same as _FixedThreadPool_/_FixedClusterPool_ numberOfThreads/numberOfWorkers, this number of workers will be always active.
a36b9e1f 36`max` (mandatory) Max number of workers that this pool can contain, the newly created workers will die after a threshold (default is 1 minute, you can override it in your worker implementation).
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37`filePath` (mandatory) Path to a file with a worker implementation.
38`opts` (optional) An object with the pool options properties described below.
a47027a0 39
7d91a8cd 40### `pool.execute(data, name, transferList)`
a47027a0 41
b51d8596 42`data` (optional) An object that you want to pass to your worker task function implementation.
637100d9 43`name` (optional) A string with the task function name that you want to execute on the worker. Default: `'default'`
5e4dbac9 44`transferList` (optional) An array of transferable objects that you want to transfer to your [`ThreadWorker`](#class-yourworker-extends-threadworkerclusterworker) worker implementation.
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45
46This method is available on both pool implementations and returns a promise with the task function execution response.
47
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48### `pool.start()`
49
50This method is available on both pool implementations and will start the minimum number of workers.
51
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52### `pool.destroy()`
53
54This method is available on both pool implementations and will call the terminate method on each worker.
55
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56### `pool.hasTaskFunction(name)`
57
679e657a 58`name` (mandatory) The task function name.
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59
60This method is available on both pool implementations and returns a boolean.
61
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62### `pool.addTaskFunction(name, fn)`
63
e7277e38 64`name` (mandatory) The task function name.
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65`fn` (mandatory) The task function.
66
67This method is available on both pool implementations and returns a boolean promise.
68
69### `pool.removeTaskFunction(name)`
70
71`name` (mandatory) The task function name.
72
73This method is available on both pool implementations and returns a boolean promise.
74
6703b9f4 75### `pool.listTaskFunctionNames()`
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76
77This method is available on both pool implementations and returns an array of the task function names.
78
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79### `pool.setDefaultTaskFunction(name)`
80
81`name` (mandatory) The task function name.
82
83This method is available on both pool implementations and returns a boolean promise.
84
31d71267 85### Pool options
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86
87An object with these properties:
88
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89- `onlineHandler` (optional) - A function that will listen for online event on each worker.
90 Default: `() => {}`
91- `messageHandler` (optional) - A function that will listen for message event on each worker.
92 Default: `() => {}`
93- `errorHandler` (optional) - A function that will listen for error event on each worker.
94 Default: `() => {}`
95- `exitHandler` (optional) - A function that will listen for exit event on each worker.
96 Default: `() => {}`
97
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98- `workerChoiceStrategy` (optional) - The worker choice strategy to use in this pool:
99
100 - `WorkerChoiceStrategies.ROUND_ROBIN`: Submit tasks to worker in a round robin fashion
101 - `WorkerChoiceStrategies.LEAST_USED`: Submit tasks to the worker with the minimum number of executed, executing and queued tasks
102 - `WorkerChoiceStrategies.LEAST_BUSY`: Submit tasks to the worker with the minimum tasks total execution and wait time
a71b05bc 103 - `WorkerChoiceStrategies.LEAST_ELU`: Submit tasks to the worker with the minimum event loop utilization (ELU)
2904fcdb 104 - `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN`: Submit tasks to worker by using a [weighted round robin scheduling algorithm](./worker-choice-strategies.md#weighted-round-robin) based on tasks execution time
bde1a004 105 - `WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN`: Submit tasks to worker by using an [interleaved weighted round robin scheduling algorithm](./worker-choice-strategies.md#interleaved-weighted-round-robin-experimental) based on tasks execution time (experimental)
2904fcdb 106 - `WorkerChoiceStrategies.FAIR_SHARE`: Submit tasks to worker by using a [fair share scheduling algorithm](./worker-choice-strategies.md#fair-share) based on tasks execution time (the default) or ELU active time
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107
108 `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN`, `WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN` and `WorkerChoiceStrategies.FAIR_SHARE` strategies are targeted to heavy and long tasks.
109 Default: `WorkerChoiceStrategies.ROUND_ROBIN`
110
111- `workerChoiceStrategyOptions` (optional) - The worker choice strategy options object to use in this pool.
112 Properties:
113
114 - `measurement` (optional) - The measurement to use in worker choice strategies: `runTime`, `waitTime` or `elu`.
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115 - `runTime` (optional) - Use the tasks [simple moving median](./worker-choice-strategies.md#simple-moving-median) runtime instead of the tasks simple moving average runtime in worker choice strategies.
116 - `waitTime` (optional) - Use the tasks [simple moving median](./worker-choice-strategies.md#simple-moving-median) wait time instead of the tasks simple moving average wait time in worker choice strategies.
117 - `elu` (optional) - Use the tasks [simple moving median](./worker-choice-strategies.md#simple-moving-median) ELU instead of the tasks simple moving average ELU in worker choice strategies.
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118 - `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.
119
26ce26ca 120 Default: `{ runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`
a47027a0 121
ce0ab2d7 122- `startWorkers` (optional) - Start the minimum number of workers at pool initialization.
d293923f 123 Default: `true`
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124- `restartWorkerOnError` (optional) - Restart worker on uncaught error in this pool.
125 Default: `true`
d67bed32 126- `enableEvents` (optional) - Pool events integrated with async resource emission enablement.
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127 Default: `true`
128- `enableTasksQueue` (optional) - Tasks queue per worker enablement in this pool.
129 Default: `false`
130
131- `tasksQueueOptions` (optional) - The worker tasks queue options object to use in this pool.
132 Properties:
133
fa3cc835 134 - `size` (optional) - The maximum number of tasks that can be queued on a worker before flagging it as back pressured. It must be a positive integer.
5137e2ae 135 - `concurrency` (optional) - The maximum number of tasks that can be executed concurrently on a worker. It must be a positive integer.
65542a35 136 - `taskStealing` (optional) - Task stealing enablement on idle.
af98b972 137 - `tasksStealingOnBackPressure` (optional) - Tasks stealing enablement under back pressure.
32b141fd 138 - `tasksFinishedTimeout` (optional) - Queued tasks finished timeout in milliseconds at worker termination.
445264e8 139
568d0075 140 Default: `{ size: (pool maximum size)^2, concurrency: 1, taskStealing: true, tasksStealingOnBackPressure: true, tasksFinishedTimeout: 2000 }`
a47027a0 141
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142- `workerOptions` (optional) - An object with the worker options to pass to worker. See [worker_threads](https://nodejs.org/api/worker_threads.html#worker_threads_new_worker_filename_options) for more details.
143
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144- `env` (optional) - An object with the environment variables to pass to worker. See [cluster](https://nodejs.org/api/cluster.html#cluster_cluster_fork_env) for more details.
145
146- `settings` (optional) - An object with the cluster settings. See [cluster](https://nodejs.org/api/cluster.html#cluster_cluster_settings) for more details.
147
148## Worker
149
150### `class YourWorker extends ThreadWorker/ClusterWorker`
151
8c445a4e 152`taskFunctions` (mandatory) The task function or task functions object `{ name_1: fn_1, ..., name_n: fn_n }` that you want to execute on the worker.
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153`opts` (optional) An object with these properties:
154
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155- `killBehavior` (optional) - Dictates if your worker will be deleted in case a task is active on it.
156 **KillBehaviors.SOFT**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker **won't** be deleted.
157 **KillBehaviors.HARD**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker will be deleted.
158 This option only apply to the newly created workers.
159 Default: `KillBehaviors.SOFT`
160
c20084b6 161- `maxInactiveTime` (optional) - Maximum waiting time in milliseconds for tasks on newly created workers. After this time newly created workers will die. It must be a positive integer greater or equal than 5.
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162 The last active time of your worker will be updated when it terminates a task.
163 If `killBehavior` is set to `KillBehaviors.HARD` this value represents also the timeout for the tasks that you submit to the pool, when this timeout expires your tasks is interrupted before completion and removed. The worker is killed if is not part of the minimum size of the pool.
164 If `killBehavior` is set to `KillBehaviors.SOFT` your tasks have no timeout and your workers will not be terminated until your task is completed.
165 Default: `60000`
166
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167- `killHandler` (optional) - A function that will be called when a worker is killed.
168 Default: `() => {}`
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169
170#### `YourWorker.hasTaskFunction(name)`
171
8c445a4e 172`name` (mandatory) The task function name.
a47027a0 173
30500265 174This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
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175
176#### `YourWorker.addTaskFunction(name, fn)`
177
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178`name` (mandatory) The task function name.
179`fn` (mandatory) The task function.
a47027a0 180
30500265 181This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
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182
183#### `YourWorker.removeTaskFunction(name)`
184
8c445a4e 185`name` (mandatory) The task function name.
a47027a0 186
30500265 187This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
a47027a0 188
6703b9f4 189#### `YourWorker.listTaskFunctionNames()`
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190
191This method is available on both worker implementations and returns an array of the task function names.
192
193#### `YourWorker.setDefaultTaskFunction(name)`
194
8c445a4e 195`name` (mandatory) The task function name.
a47027a0 196
30500265 197This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.