perf: remove unneeded condition in tasks stealing code
[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)
a47027a0 9 - [`pool.destroy()`](#pooldestroy)
90d7d101 10 - [`pool.listTaskFunctions()`](#poollisttaskfunctions)
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11 - [`PoolOptions`](#pooloptions)
12 - [`ThreadPoolOptions extends PoolOptions`](#threadpooloptions-extends-pooloptions)
13 - [`ClusterPoolOptions extends PoolOptions`](#clusterpooloptions-extends-pooloptions)
14- [Worker](#worker)
15 - [`class YourWorker extends ThreadWorker/ClusterWorker`](#class-yourworker-extends-threadworkerclusterworker)
16 - [`YourWorker.hasTaskFunction(name)`](#yourworkerhastaskfunctionname)
17 - [`YourWorker.addTaskFunction(name, fn)`](#yourworkeraddtaskfunctionname-fn)
18 - [`YourWorker.removeTaskFunction(name)`](#yourworkerremovetaskfunctionname)
19 - [`YourWorker.listTaskFunctions()`](#yourworkerlisttaskfunctions)
20 - [`YourWorker.setDefaultTaskFunction(name)`](#yourworkersetdefaulttaskfunctionname)
21
22## Pool
23
24### `pool = new FixedThreadPool/FixedClusterPool(numberOfThreads/numberOfWorkers, filePath, opts)`
25
26`numberOfThreads/numberOfWorkers` (mandatory) Number of workers for this pool
27`filePath` (mandatory) Path to a file with a worker implementation
28`opts` (optional) An object with the pool options properties described below
29
30### `pool = new DynamicThreadPool/DynamicClusterPool(min, max, filePath, opts)`
31
32`min` (mandatory) Same as _FixedThreadPool_/_FixedClusterPool_ numberOfThreads/numberOfWorkers, this number of workers will be always active
33`max` (mandatory) Max number of workers that this pool can contain, the new created workers will die after a threshold (default is 1 minute, you can override it in your worker implementation).
34`filePath` (mandatory) Path to a file with a worker implementation
35`opts` (optional) An object with the pool options properties described below
36
7d91a8cd 37### `pool.execute(data, name, transferList)`
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38
39`data` (optional) An object that you want to pass to your worker implementation
637100d9 40`name` (optional) A string with the task function name that you want to execute on the worker. Default: `'default'`
7d91a8cd 41`transferList` (optional) An array of transferable objects that you want to transfer to your [worker_threads](https://nodejs.org/api/worker_threads.html) worker implementation
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42
43This method is available on both pool implementations and returns a promise with the task function execution response.
44
45### `pool.destroy()`
46
47This method is available on both pool implementations and will call the terminate method on each worker.
48
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49### `pool.listTaskFunctions()`
50
51This method is available on both pool implementations and returns an array of the task function names.
52
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53### `PoolOptions`
54
55An object with these properties:
56
c6ad8edf 57- `onlineHandler` (optional) - A function that will listen for online event on each worker
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58- `messageHandler` (optional) - A function that will listen for message event on each worker
59- `errorHandler` (optional) - A function that will listen for error event on each worker
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60- `exitHandler` (optional) - A function that will listen for exit event on each worker
61- `workerChoiceStrategy` (optional) - The worker choice strategy to use in this pool:
62
63 - `WorkerChoiceStrategies.ROUND_ROBIN`: Submit tasks to worker in a round robin fashion
64 - `WorkerChoiceStrategies.LEAST_USED`: Submit tasks to the worker with the minimum number of executed, executing and queued tasks
65 - `WorkerChoiceStrategies.LEAST_BUSY`: Submit tasks to the worker with the minimum tasks total execution and wait time
a71b05bc 66 - `WorkerChoiceStrategies.LEAST_ELU`: Submit tasks to the worker with the minimum event loop utilization (ELU)
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67 - `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
68 - `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) based on tasks execution time (experimental)
69 - `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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70
71 `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN`, `WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN` and `WorkerChoiceStrategies.FAIR_SHARE` strategies are targeted to heavy and long tasks.
72 Default: `WorkerChoiceStrategies.ROUND_ROBIN`
73
74- `workerChoiceStrategyOptions` (optional) - The worker choice strategy options object to use in this pool.
75 Properties:
76
8990357d 77 - `choiceRetries` (optional) - The number of retries to perform if no worker is eligible.
a47027a0 78 - `measurement` (optional) - The measurement to use in worker choice strategies: `runTime`, `waitTime` or `elu`.
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79 - `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.
80 - `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.
81 - `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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82 - `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.
83
8990357d 84 Default: `{ choiceRetries: 6, runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`
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85
86- `restartWorkerOnError` (optional) - Restart worker on uncaught error in this pool.
87 Default: `true`
88- `enableEvents` (optional) - Events emission enablement in this pool.
89 Default: `true`
90- `enableTasksQueue` (optional) - Tasks queue per worker enablement in this pool.
91 Default: `false`
92
93- `tasksQueueOptions` (optional) - The worker tasks queue options object to use in this pool.
94 Properties:
95
fa3cc835 96 - `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 97 - `concurrency` (optional) - The maximum number of tasks that can be executed concurrently on a worker. It must be a positive integer.
445264e8 98
fa3cc835 99 Default: `{ size: (pool maximum size)^2, concurrency: 1 }`
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100
101#### `ThreadPoolOptions extends PoolOptions`
102
103- `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.
104
105#### `ClusterPoolOptions extends PoolOptions`
106
107- `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.
108
109- `settings` (optional) - An object with the cluster settings. See [cluster](https://nodejs.org/api/cluster.html#cluster_cluster_settings) for more details.
110
111## Worker
112
113### `class YourWorker extends ThreadWorker/ClusterWorker`
114
115`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
116`opts` (optional) An object with these properties:
117
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118- `killBehavior` (optional) - Dictates if your worker will be deleted in case a task is active on it.
119 **KillBehaviors.SOFT**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker **won't** be deleted.
120 **KillBehaviors.HARD**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker will be deleted.
121 This option only apply to the newly created workers.
122 Default: `KillBehaviors.SOFT`
123
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124- `maxInactiveTime` (optional) - Maximum waiting time in milliseconds for tasks on newly created workers. After this time newly created workers will die.
125 The last active time of your worker will be updated when it terminates a task.
126 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.
127 If `killBehavior` is set to `KillBehaviors.SOFT` your tasks have no timeout and your workers will not be terminated until your task is completed.
128 Default: `60000`
129
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130- `killHandler` (optional) - A function that will be called when a worker is killed.
131 Default: `() => {}`
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132
133#### `YourWorker.hasTaskFunction(name)`
134
135`name` (mandatory) The task function name
136
137This method is available on both worker implementations and returns a boolean.
138
139#### `YourWorker.addTaskFunction(name, fn)`
140
141`name` (mandatory) The task function name
142`fn` (mandatory) The task function
143
144This method is available on both worker implementations and returns a boolean.
145
146#### `YourWorker.removeTaskFunction(name)`
147
148`name` (mandatory) The task function name
149
150This method is available on both worker implementations and returns a boolean.
151
152#### `YourWorker.listTaskFunctions()`
153
154This method is available on both worker implementations and returns an array of the task function names.
155
156#### `YourWorker.setDefaultTaskFunction(name)`
157
158`name` (mandatory) The task function name
159
160This method is available on both worker implementations and returns a boolean.