[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.destroy()`](#pooldestroy)
  - [`pool.listTaskFunctions()`](#poollisttaskfunctions)
  - [`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.listTaskFunctions()`](#yourworkerlisttaskfunctions)
    - [`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 new 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.destroy()`

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

### `pool.listTaskFunctions()`

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
- `messageHandler` (optional) - A function that will listen for message event on each worker
- `errorHandler` (optional) - A function that will listen for error event on each worker
- `exitHandler` (optional) - A function that will listen for exit event on each worker
- `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 } }`

- `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.

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

#### `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.  
  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 a boolean.

#### `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 a boolean.

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

`name` (mandatory) The task function name

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

#### `YourWorker.listTaskFunctions()`

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 a boolean.
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)
a47027a0	9	- [`pool.destroy()`](#pooldestroy)
90d7d101	10	- [`pool.listTaskFunctions()`](#poollisttaskfunctions)
a47027a0 JB	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)`
a47027a0 JB	38
a47027a0 JB	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
a47027a0 JB	42
	43	This method is available on both pool implementations and returns a promise with the task function execution response.
	44
	45	### `pool.destroy()`
	46
	47	This method is available on both pool implementations and will call the terminate method on each worker.
	48
90d7d101 JB	49	### `pool.listTaskFunctions()`
	50
	51	This method is available on both pool implementations and returns an array of the task function names.
	52
a47027a0 JB	53	### `PoolOptions`
	54
	55	An object with these properties:
	56
c6ad8edf	57	- `onlineHandler` (optional) - A function that will listen for online event on each worker
a47027a0 JB	58	- `messageHandler` (optional) - A function that will listen for message event on each worker
a47027a0 JB	59	- `errorHandler` (optional) - A function that will listen for error event on each worker
a47027a0 JB	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)
2904fcdb	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
bde1a004	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-experimental) based on tasks execution time (experimental)
2904fcdb	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
a47027a0 JB	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
8c0b113f	77	- `retries` (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`.
06916f85 JB	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.
a47027a0 JB	82	- `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.
a47027a0 JB	83
8c0b113f	84	Default: `{ retries: 6, runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`
a47027a0 JB	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 }`
a47027a0 JB	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
968dbbe7 JB	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
a47027a0 JB	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
968dbbe7 JB	130	- `killHandler` (optional) - A function that will be called when a worker is killed.
968dbbe7 JB	131	Default: `() => {}`
a47027a0 JB	132
	133	#### `YourWorker.hasTaskFunction(name)`
	134
	135	`name` (mandatory) The task function name
	136
	137	This 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
	144	This 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
	150	This method is available on both worker implementations and returns a boolean.
	151
	152	#### `YourWorker.listTaskFunctions()`
	153
	154	This 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
	160	This method is available on both worker implementations and returns a boolean.