[poolifier.git] / docs / api.md

# [API](https://poolifier.github.io/poolifier/)

## Table of contents

- [Pool](#pool)
  - [`pool = new FixedThreadPool/FixedClusterPool(numberOfThreads/numberOfWorkers, filePath, opts)`](#pool--new-fixedthreadpoolfixedclusterpoolnumberofthreadsnumberofworkers-filepath-opts)
  - [`pool = new DynamicThreadPool/DynamicClusterPool(min, max, filePath, opts)`](#pool--new-dynamicthreadpooldynamicclusterpoolmin-max-filepath-opts)
  - [`pool.execute(data, name, transferList)`](#poolexecutedata-name-transferlist)
  - [`pool.start()`](#poolstart)
  - [`pool.destroy()`](#pooldestroy)
  - [`pool.listTaskFunctionNames()`](#poollisttaskfunctionnames)
  - [`PoolOptions`](#pooloptions)
    - [`ThreadPoolOptions extends PoolOptions`](#threadpooloptions-extends-pooloptions)
    - [`ClusterPoolOptions extends PoolOptions`](#clusterpooloptions-extends-pooloptions)
- [Worker](#worker)
  - [`class YourWorker extends ThreadWorker/ClusterWorker`](#class-yourworker-extends-threadworkerclusterworker)
    - [`YourWorker.hasTaskFunction(name)`](#yourworkerhastaskfunctionname)
    - [`YourWorker.addTaskFunction(name, fn)`](#yourworkeraddtaskfunctionname-fn)
    - [`YourWorker.removeTaskFunction(name)`](#yourworkerremovetaskfunctionname)
    - [`YourWorker.listTaskFunctionNames()`](#yourworkerlisttaskfunctionnames)
    - [`YourWorker.setDefaultTaskFunction(name)`](#yourworkersetdefaulttaskfunctionname)

## Pool

### `pool = new FixedThreadPool/FixedClusterPool(numberOfThreads/numberOfWorkers, filePath, opts)`

`numberOfThreads/numberOfWorkers` (mandatory) Number of workers for this pool.  
`filePath` (mandatory) Path to a file with a worker implementation.  
`opts` (optional) An object with the pool options properties described below.

### `pool = new DynamicThreadPool/DynamicClusterPool(min, max, filePath, opts)`

`min` (mandatory) Same as _FixedThreadPool_/_FixedClusterPool_ numberOfThreads/numberOfWorkers, this number of workers will be always active.  
`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).  
`filePath` (mandatory) Path to a file with a worker implementation.  
`opts` (optional) An object with the pool options properties described below.

### `pool.execute(data, name, transferList)`

`data` (optional) An object that you want to pass to your worker implementation.  
`name` (optional) A string with the task function name that you want to execute on the worker. Default: `'default'`  
`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

This method is available on both pool implementations and returns a promise with the task function execution response.

### `pool.start()`

This method is available on both pool implementations and will start the minimum number of workers.

### `pool.destroy()`

This method is available on both pool implementations and will call the terminate method on each worker.

### `pool.hasTaskFunction(name)`

`name` (mandatory) The task function name

This method is available on both pool implementations and returns a boolean.

### `pool.listTaskFunctionNames()`

This method is available on both pool implementations and returns an array of the task function names.

### `PoolOptions`

An object with these properties:

- `onlineHandler` (optional) - A function that will listen for online event on each worker.  
  Default: `() => {}`
- `messageHandler` (optional) - A function that will listen for message event on each worker.  
  Default: `() => {}`
- `errorHandler` (optional) - A function that will listen for error event on each worker.  
  Default: `() => {}`
- `exitHandler` (optional) - A function that will listen for exit event on each worker.  
  Default: `() => {}`

- `workerChoiceStrategy` (optional) - The worker choice strategy to use in this pool:

  - `WorkerChoiceStrategies.ROUND_ROBIN`: Submit tasks to worker in a round robin fashion
  - `WorkerChoiceStrategies.LEAST_USED`: Submit tasks to the worker with the minimum number of executed, executing and queued tasks
  - `WorkerChoiceStrategies.LEAST_BUSY`: Submit tasks to the worker with the minimum tasks total execution and wait time
  - `WorkerChoiceStrategies.LEAST_ELU`: Submit tasks to the worker with the minimum event loop utilization (ELU)
  - `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
  - `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)
  - `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

  `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN`, `WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN` and `WorkerChoiceStrategies.FAIR_SHARE` strategies are targeted to heavy and long tasks.  
  Default: `WorkerChoiceStrategies.ROUND_ROBIN`

- `workerChoiceStrategyOptions` (optional) - The worker choice strategy options object to use in this pool.  
  Properties:

  - `retries` (optional) - The number of retries to perform if no worker is eligible.
  - `measurement` (optional) - The measurement to use in worker choice strategies: `runTime`, `waitTime` or `elu`.
  - `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.
  - `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.
  - `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.
  - `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.

  Default: `{ retries: 6, runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`

- `startWorkers` (optional) - Start the minimum number of workers at pool creation.  
  Default: `true`
- `restartWorkerOnError` (optional) - Restart worker on uncaught error in this pool.  
  Default: `true`
- `enableEvents` (optional) - Events emission enablement in this pool.  
  Default: `true`
- `enableTasksQueue` (optional) - Tasks queue per worker enablement in this pool.  
  Default: `false`

- `tasksQueueOptions` (optional) - The worker tasks queue options object to use in this pool.  
  Properties:

  - `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.
  - `concurrency` (optional) - The maximum number of tasks that can be executed concurrently on a worker. It must be a positive integer.
  - `taskStealing` (optional) - Task stealing enablement.
  - `tasksStealingOnBackPressure` (optional) - Tasks stealing enablement on back pressure.

  Default: `{ size: (pool maximum size)^2, concurrency: 1, taskStealing: true, tasksStealingOnBackPressure: true }`

#### `ThreadPoolOptions extends PoolOptions`

- `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.

#### `ClusterPoolOptions extends PoolOptions`

- `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.

- `settings` (optional) - An object with the cluster settings. See [cluster](https://nodejs.org/api/cluster.html#cluster_cluster_settings) for more details.

## Worker

### `class YourWorker extends ThreadWorker/ClusterWorker`

`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.  
`opts` (optional) An object with these properties:

- `killBehavior` (optional) - Dictates if your worker will be deleted in case a task is active on it.  
  **KillBehaviors.SOFT**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker **won't** be deleted.  
  **KillBehaviors.HARD**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker will be deleted.  
  This option only apply to the newly created workers.  
  Default: `KillBehaviors.SOFT`

- `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.  
  The last active time of your worker will be updated when it terminates a task.  
  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.  
  If `killBehavior` is set to `KillBehaviors.SOFT` your tasks have no timeout and your workers will not be terminated until your task is completed.  
  Default: `60000`

- `killHandler` (optional) - A function that will be called when a worker is killed.  
  Default: `() => {}`

#### `YourWorker.hasTaskFunction(name)`

`name` (mandatory) The task function name.

This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.

#### `YourWorker.addTaskFunction(name, fn)`

`name` (mandatory) The task function name.  
`fn` (mandatory) The task function.

This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.

#### `YourWorker.removeTaskFunction(name)`

`name` (mandatory) The task function name.

This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.

#### `YourWorker.listTaskFunctionNames()`

This method is available on both worker implementations and returns an array of the task function names.

#### `YourWorker.setDefaultTaskFunction(name)`

`name` (mandatory) The task function name.

This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
Commit	Line	Data
a47027a0 JB	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)
6703b9f4	11	- [`pool.listTaskFunctionNames()`](#poollisttaskfunctionnames)
a47027a0 JB	12	- [`PoolOptions`](#pooloptions)
	13	- [`ThreadPoolOptions extends PoolOptions`](#threadpooloptions-extends-pooloptions)
	14	- [`ClusterPoolOptions extends PoolOptions`](#clusterpooloptions-extends-pooloptions)
	15	- [Worker](#worker)
	16	- [`class YourWorker extends ThreadWorker/ClusterWorker`](#class-yourworker-extends-threadworkerclusterworker)
	17	- [`YourWorker.hasTaskFunction(name)`](#yourworkerhastaskfunctionname)
	18	- [`YourWorker.addTaskFunction(name, fn)`](#yourworkeraddtaskfunctionname-fn)
	19	- [`YourWorker.removeTaskFunction(name)`](#yourworkerremovetaskfunctionname)
6703b9f4	20	- [`YourWorker.listTaskFunctionNames()`](#yourworkerlisttaskfunctionnames)
a47027a0 JB	21	- [`YourWorker.setDefaultTaskFunction(name)`](#yourworkersetdefaulttaskfunctionname)
	22
	23	## Pool
	24
	25	### `pool = new FixedThreadPool/FixedClusterPool(numberOfThreads/numberOfWorkers, filePath, opts)`
	26
8c445a4e JB	27	`numberOfThreads/numberOfWorkers` (mandatory) Number of workers for this pool.
	28	`filePath` (mandatory) Path to a file with a worker implementation.
	29	`opts` (optional) An object with the pool options properties described below.
a47027a0 JB	30
	31	### `pool = new DynamicThreadPool/DynamicClusterPool(min, max, filePath, opts)`
	32
8c445a4e	33	`min` (mandatory) Same as _FixedThreadPool_/_FixedClusterPool_ numberOfThreads/numberOfWorkers, this number of workers will be always active.
a36b9e1f	34	`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).
8c445a4e JB	35	`filePath` (mandatory) Path to a file with a worker implementation.
8c445a4e JB	36	`opts` (optional) An object with the pool options properties described below.
a47027a0	37
7d91a8cd	38	### `pool.execute(data, name, transferList)`
a47027a0	39
8c445a4e	40	`data` (optional) An object that you want to pass to your worker implementation.
637100d9	41	`name` (optional) A string with the task function name that you want to execute on the worker. Default: `'default'`
7d91a8cd	42	`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
a47027a0 JB	43
	44	This method is available on both pool implementations and returns a promise with the task function execution response.
	45
47352846 JB	46	### `pool.start()`
	47
	48	This method is available on both pool implementations and will start the minimum number of workers.
	49
a47027a0 JB	50	### `pool.destroy()`
	51
	52	This method is available on both pool implementations and will call the terminate method on each worker.
	53
30500265 JB	54	### `pool.hasTaskFunction(name)`
	55
	56	`name` (mandatory) The task function name
	57
	58	This method is available on both pool implementations and returns a boolean.
	59
6703b9f4	60	### `pool.listTaskFunctionNames()`
90d7d101 JB	61
	62	This method is available on both pool implementations and returns an array of the task function names.
	63
a47027a0 JB	64	### `PoolOptions`
	65
	66	An object with these properties:
	67
d293923f JB	68	- `onlineHandler` (optional) - A function that will listen for online event on each worker.
	69	Default: `() => {}`
	70	- `messageHandler` (optional) - A function that will listen for message event on each worker.
	71	Default: `() => {}`
	72	- `errorHandler` (optional) - A function that will listen for error event on each worker.
	73	Default: `() => {}`
	74	- `exitHandler` (optional) - A function that will listen for exit event on each worker.
	75	Default: `() => {}`
	76
a47027a0 JB	77	- `workerChoiceStrategy` (optional) - The worker choice strategy to use in this pool:
	78
	79	- `WorkerChoiceStrategies.ROUND_ROBIN`: Submit tasks to worker in a round robin fashion
	80	- `WorkerChoiceStrategies.LEAST_USED`: Submit tasks to the worker with the minimum number of executed, executing and queued tasks
	81	- `WorkerChoiceStrategies.LEAST_BUSY`: Submit tasks to the worker with the minimum tasks total execution and wait time
a71b05bc	82	- `WorkerChoiceStrategies.LEAST_ELU`: Submit tasks to the worker with the minimum event loop utilization (ELU)
2904fcdb	83	- `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	84	- `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	85	- `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
a47027a0 JB	86
	87	`WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN`, `WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN` and `WorkerChoiceStrategies.FAIR_SHARE` strategies are targeted to heavy and long tasks.
	88	Default: `WorkerChoiceStrategies.ROUND_ROBIN`
	89
	90	- `workerChoiceStrategyOptions` (optional) - The worker choice strategy options object to use in this pool.
	91	Properties:
	92
8c0b113f	93	- `retries` (optional) - The number of retries to perform if no worker is eligible.
a47027a0	94	- `measurement` (optional) - The measurement to use in worker choice strategies: `runTime`, `waitTime` or `elu`.
06916f85 JB	95	- `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.
	96	- `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.
	97	- `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.
a47027a0 JB	98	- `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.
a47027a0 JB	99
8c0b113f	100	Default: `{ retries: 6, runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`
a47027a0	101
d293923f JB	102	- `startWorkers` (optional) - Start the minimum number of workers at pool creation.
d293923f JB	103	Default: `true`
a47027a0 JB	104	- `restartWorkerOnError` (optional) - Restart worker on uncaught error in this pool.
	105	Default: `true`
	106	- `enableEvents` (optional) - Events emission enablement in this pool.
	107	Default: `true`
	108	- `enableTasksQueue` (optional) - Tasks queue per worker enablement in this pool.
	109	Default: `false`
	110
	111	- `tasksQueueOptions` (optional) - The worker tasks queue options object to use in this pool.
	112	Properties:
	113
fa3cc835	114	- `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	115	- `concurrency` (optional) - The maximum number of tasks that can be executed concurrently on a worker. It must be a positive integer.
d293923f	116	- `taskStealing` (optional) - Task stealing enablement.
47352846	117	- `tasksStealingOnBackPressure` (optional) - Tasks stealing enablement on back pressure.
445264e8	118
dbd73092	119	Default: `{ size: (pool maximum size)^2, concurrency: 1, taskStealing: true, tasksStealingOnBackPressure: true }`
a47027a0 JB	120
	121	#### `ThreadPoolOptions extends PoolOptions`
	122
	123	- `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.
	124
	125	#### `ClusterPoolOptions extends PoolOptions`
	126
	127	- `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.
	128
	129	- `settings` (optional) - An object with the cluster settings. See [cluster](https://nodejs.org/api/cluster.html#cluster_cluster_settings) for more details.
	130
	131	## Worker
	132
	133	### `class YourWorker extends ThreadWorker/ClusterWorker`
	134
8c445a4e	135	`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.
a47027a0 JB	136	`opts` (optional) An object with these properties:
a47027a0 JB	137
968dbbe7 JB	138	- `killBehavior` (optional) - Dictates if your worker will be deleted in case a task is active on it.
	139	KillBehaviors.SOFT: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker won't be deleted.
	140	KillBehaviors.HARD: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker will be deleted.
	141	This option only apply to the newly created workers.
	142	Default: `KillBehaviors.SOFT`
	143
c20084b6	144	- `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.
a47027a0 JB	145	The last active time of your worker will be updated when it terminates a task.
	146	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.
	147	If `killBehavior` is set to `KillBehaviors.SOFT` your tasks have no timeout and your workers will not be terminated until your task is completed.
	148	Default: `60000`
	149
968dbbe7 JB	150	- `killHandler` (optional) - A function that will be called when a worker is killed.
968dbbe7 JB	151	Default: `() => {}`
a47027a0 JB	152
	153	#### `YourWorker.hasTaskFunction(name)`
	154
8c445a4e	155	`name` (mandatory) The task function name.
a47027a0	156
30500265	157	This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
a47027a0 JB	158
	159	#### `YourWorker.addTaskFunction(name, fn)`
	160
8c445a4e JB	161	`name` (mandatory) The task function name.
8c445a4e JB	162	`fn` (mandatory) The task function.
a47027a0	163
30500265	164	This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
a47027a0 JB	165
	166	#### `YourWorker.removeTaskFunction(name)`
	167
8c445a4e	168	`name` (mandatory) The task function name.
a47027a0	169
30500265	170	This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
a47027a0	171
6703b9f4	172	#### `YourWorker.listTaskFunctionNames()`
a47027a0 JB	173
	174	This method is available on both worker implementations and returns an array of the task function names.
	175
	176	#### `YourWorker.setDefaultTaskFunction(name)`
	177
8c445a4e	178	`name` (mandatory) The task function name.
a47027a0	179
30500265	180	This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.