docs/api.md

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