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.listTaskFunctions()`](#poollisttaskfunctions)
  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.listTaskFunctions()`](#yourworkerlisttaskfunctions)
  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.listTaskFunctions()`
  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 - `messageHandler` (optional) - A function that will listen for message event on each worker
  64 - `errorHandler` (optional) - A function that will listen for error event on each worker
  65 - `exitHandler` (optional) - A function that will listen for exit event on each worker
  66 - `startWorkers` (optional) - Start the minimum number of workers at pool creation.
  67   Default: `true`
  68 - `workerChoiceStrategy` (optional) - The worker choice strategy to use in this pool:
  69
  70   - `WorkerChoiceStrategies.ROUND_ROBIN`: Submit tasks to worker in a round robin fashion
  71   - `WorkerChoiceStrategies.LEAST_USED`: Submit tasks to the worker with the minimum number of executed, executing and queued tasks
  72   - `WorkerChoiceStrategies.LEAST_BUSY`: Submit tasks to the worker with the minimum tasks total execution and wait time
  73   - `WorkerChoiceStrategies.LEAST_ELU`: Submit tasks to the worker with the minimum event loop utilization (ELU)
  74   - `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
  75   - `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)
  76   - `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
  77
  78   `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN`, `WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN` and `WorkerChoiceStrategies.FAIR_SHARE` strategies are targeted to heavy and long tasks.
  79   Default: `WorkerChoiceStrategies.ROUND_ROBIN`
  80
  81 - `workerChoiceStrategyOptions` (optional) - The worker choice strategy options object to use in this pool.
  82   Properties:
  83
  84   - `retries` (optional) - The number of retries to perform if no worker is eligible.
  85   - `measurement` (optional) - The measurement to use in worker choice strategies: `runTime`, `waitTime` or `elu`.
  86   - `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.
  87   - `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.
  88   - `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.
  89   - `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.
  90
  91   Default: `{ retries: 6, runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`
  92
  93 - `restartWorkerOnError` (optional) - Restart worker on uncaught error in this pool.
  94   Default: `true`
  95 - `enableEvents` (optional) - Events emission enablement in this pool.
  96   Default: `true`
  97 - `enableTasksQueue` (optional) - Tasks queue per worker enablement in this pool.
  98   Default: `false`
  99
 100 - `tasksQueueOptions` (optional) - The worker tasks queue options object to use in this pool.
 101   Properties:
 102
 103   - `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.
 104   - `concurrency` (optional) - The maximum number of tasks that can be executed concurrently on a worker. It must be a positive integer.
 105   - `tasksStealing` (optional) - Tasks stealing enablement.
 106   - `tasksStealingOnBackPressure` (optional) - Tasks stealing enablement on back pressure.
 107
 108   Default: `{ size: (pool maximum size)^2, concurrency: 1, tasksStealing: true, tasksStealingOnBackPressure: true }`
 109
 110 #### `ThreadPoolOptions extends PoolOptions`
 111
 112 - `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.
 113
 114 #### `ClusterPoolOptions extends PoolOptions`
 115
 116 - `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.
 117
 118 - `settings` (optional) - An object with the cluster settings. See [cluster](https://nodejs.org/api/cluster.html#cluster_cluster_settings) for more details.
 119
 120 ## Worker
 121
 122 ### `class YourWorker extends ThreadWorker/ClusterWorker`
 123
 124 `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
 125 `opts` (optional) An object with these properties:
 126
 127 - `killBehavior` (optional) - Dictates if your worker will be deleted in case a task is active on it.
 128   **KillBehaviors.SOFT**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker **won't** be deleted.
 129   **KillBehaviors.HARD**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker will be deleted.
 130   This option only apply to the newly created workers.
 131   Default: `KillBehaviors.SOFT`
 132
 133 - `maxInactiveTime` (optional) - Maximum waiting time in milliseconds for tasks on newly created workers. After this time newly created workers will die.
 134   The last active time of your worker will be updated when it terminates a task.
 135   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.
 136   If `killBehavior` is set to `KillBehaviors.SOFT` your tasks have no timeout and your workers will not be terminated until your task is completed.
 137   Default: `60000`
 138
 139 - `killHandler` (optional) - A function that will be called when a worker is killed.
 140   Default: `() => {}`
 141
 142 #### `YourWorker.hasTaskFunction(name)`
 143
 144 `name` (mandatory) The task function name
 145
 146 This method is available on both worker implementations and returns a boolean.
 147
 148 #### `YourWorker.addTaskFunction(name, fn)`
 149
 150 `name` (mandatory) The task function name
 151 `fn` (mandatory) The task function
 152
 153 This method is available on both worker implementations and returns a boolean.
 154
 155 #### `YourWorker.removeTaskFunction(name)`
 156
 157 `name` (mandatory) The task function name
 158
 159 This method is available on both worker implementations and returns a boolean.
 160
 161 #### `YourWorker.listTaskFunctions()`
 162
 163 This method is available on both worker implementations and returns an array of the task function names.
 164
 165 #### `YourWorker.setDefaultTaskFunction(name)`
 166
 167 `name` (mandatory) The task function name
 168
 169 This method is available on both worker implementations and returns a boolean.