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.destroy()`](#pooldestroy)
  10   - [`pool.listTaskFunctionNames()`](#poollisttaskfunctionnames)
  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.listTaskFunctionNames()`](#yourworkerlisttaskfunctionnames)
  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 newly 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
  37 ### `pool.execute(data, name, transferList)`
  38
  39 `data` (optional) An object that you want to pass to your worker implementation
  40 `name` (optional) A string with the task function name that you want to execute on the worker. Default: `'default'`
  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
  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
  49 ### `pool.listTaskFunctionNames()`
  50
  51 This method is available on both pool implementations and returns an array of the task function names.
  52
  53 ### `PoolOptions`
  54
  55 An object with these properties:
  56
  57 - `onlineHandler` (optional) - A function that will listen for online event on each worker
  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
  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
  66   - `WorkerChoiceStrategies.LEAST_ELU`: Submit tasks to the worker with the minimum event loop utilization (ELU)
  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-experimental) 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
  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
  77   - `retries` (optional) - The number of retries to perform if no worker is eligible.
  78   - `measurement` (optional) - The measurement to use in worker choice strategies: `runTime`, `waitTime` or `elu`.
  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.
  82   - `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.
  83
  84   Default: `{ retries: 6, runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`
  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
  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.
  97   - `concurrency` (optional) - The maximum number of tasks that can be executed concurrently on a worker. It must be a positive integer.
  98
  99   Default: `{ size: (pool maximum size)^2, concurrency: 1 }`
 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
 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
 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
 130 - `killHandler` (optional) - A function that will be called when a worker is killed.
 131   Default: `() => {}`
 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.listTaskFunctionNames()`
 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.