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.hasTaskFunction(name)`](#poolhastaskfunctionname)
  12   - [`pool.addTaskFunction(name, fn)`](#pooladdtaskfunctionname-fn)
  13   - [`pool.removeTaskFunction(name)`](#poolremovetaskfunctionname)
  14   - [`pool.listTaskFunctionNames()`](#poollisttaskfunctionnames)
  15   - [`pool.setDefaultTaskFunction(name)`](#poolsetdefaulttaskfunctionname)
  16   - [Pool options](#pool-options)
  17 - [Worker](#worker)
  18   - [`class YourWorker extends ThreadWorker/ClusterWorker`](#class-yourworker-extends-threadworkerclusterworker)
  19     - [`YourWorker.hasTaskFunction(name)`](#yourworkerhastaskfunctionname)
  20     - [`YourWorker.addTaskFunction(name, fn)`](#yourworkeraddtaskfunctionname-fn)
  21     - [`YourWorker.removeTaskFunction(name)`](#yourworkerremovetaskfunctionname)
  22     - [`YourWorker.listTaskFunctionNames()`](#yourworkerlisttaskfunctionnames)
  23     - [`YourWorker.setDefaultTaskFunction(name)`](#yourworkersetdefaulttaskfunctionname)
  24
  25 ## Pool
  26
  27 ### `pool = new FixedThreadPool/FixedClusterPool(numberOfThreads/numberOfWorkers, filePath, opts)`
  28
  29 `numberOfThreads/numberOfWorkers` (mandatory) Number of workers for this pool.
  30 `filePath` (mandatory) Path to a file with a worker implementation.
  31 `opts` (optional) An object with the pool options properties described below.
  32
  33 ### `pool = new DynamicThreadPool/DynamicClusterPool(min, max, filePath, opts)`
  34
  35 `min` (mandatory) Same as _FixedThreadPool_/_FixedClusterPool_ numberOfThreads/numberOfWorkers, this number of workers will be always active.
  36 `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).
  37 `filePath` (mandatory) Path to a file with a worker implementation.
  38 `opts` (optional) An object with the pool options properties described below.
  39
  40 ### `pool.execute(data, name, transferList)`
  41
  42 `data` (optional) An object that you want to pass to your worker task function implementation.
  43 `name` (optional) A string with the task function name that you want to execute on the worker. Default: `'default'`
  44 `transferList` (optional) An array of transferable objects that you want to transfer to your [`ThreadWorker`](#class-yourworker-extends-threadworkerclusterworker) worker implementation.
  45
  46 This method is available on both pool implementations and returns a promise with the task function execution response.
  47
  48 ### `pool.start()`
  49
  50 This method is available on both pool implementations and will start the minimum number of workers.
  51
  52 ### `pool.destroy()`
  53
  54 This method is available on both pool implementations and will call the terminate method on each worker.
  55
  56 ### `pool.hasTaskFunction(name)`
  57
  58 `name` (mandatory) The task function name.
  59
  60 This method is available on both pool implementations and returns a boolean.
  61
  62 ### `pool.addTaskFunction(name, fn)`
  63
  64 `name` (mandatory) The task function name.
  65 `fn` (mandatory) The task function.
  66
  67 This method is available on both pool implementations and returns a boolean promise.
  68
  69 ### `pool.removeTaskFunction(name)`
  70
  71 `name` (mandatory) The task function name.
  72
  73 This method is available on both pool implementations and returns a boolean promise.
  74
  75 ### `pool.listTaskFunctionNames()`
  76
  77 This method is available on both pool implementations and returns an array of the task function names.
  78
  79 ### `pool.setDefaultTaskFunction(name)`
  80
  81 `name` (mandatory) The task function name.
  82
  83 This method is available on both pool implementations and returns a boolean promise.
  84
  85 ### Pool options
  86
  87 An object with these properties:
  88
  89 - `onlineHandler` (optional) - A function that will listen for online event on each worker.
  90   Default: `() => {}`
  91 - `messageHandler` (optional) - A function that will listen for message event on each worker.
  92   Default: `() => {}`
  93 - `errorHandler` (optional) - A function that will listen for error event on each worker.
  94   Default: `() => {}`
  95 - `exitHandler` (optional) - A function that will listen for exit event on each worker.
  96   Default: `() => {}`
  97
  98 - `workerChoiceStrategy` (optional) - The worker choice strategy to use in this pool:
  99
 100   - `WorkerChoiceStrategies.ROUND_ROBIN`: Submit tasks to worker in a round robin fashion
 101   - `WorkerChoiceStrategies.LEAST_USED`: Submit tasks to the worker with the minimum number of executed, executing and queued tasks
 102   - `WorkerChoiceStrategies.LEAST_BUSY`: Submit tasks to the worker with the minimum tasks total execution and wait time
 103   - `WorkerChoiceStrategies.LEAST_ELU`: Submit tasks to the worker with the minimum event loop utilization (ELU)
 104   - `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
 105   - `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)
 106   - `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
 107
 108   `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN`, `WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN` and `WorkerChoiceStrategies.FAIR_SHARE` strategies are targeted to heavy and long tasks.
 109   Default: `WorkerChoiceStrategies.ROUND_ROBIN`
 110
 111 - `workerChoiceStrategyOptions` (optional) - The worker choice strategy options object to use in this pool.
 112   Properties:
 113
 114   - `measurement` (optional) - The measurement to use in worker choice strategies: `runTime`, `waitTime` or `elu`.
 115   - `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.
 116   - `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.
 117   - `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.
 118   - `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.
 119
 120   Default: `{ runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`
 121
 122 - `startWorkers` (optional) - Start the minimum number of workers at pool initialization.
 123   Default: `true`
 124 - `restartWorkerOnError` (optional) - Restart worker on uncaught error in this pool.
 125   Default: `true`
 126 - `enableEvents` (optional) - Events integrated with async resource emission enablement in this pool.
 127   Default: `true`
 128 - `enableTasksQueue` (optional) - Tasks queue per worker enablement in this pool.
 129   Default: `false`
 130
 131 - `tasksQueueOptions` (optional) - The worker tasks queue options object to use in this pool.
 132   Properties:
 133
 134   - `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.
 135   - `concurrency` (optional) - The maximum number of tasks that can be executed concurrently on a worker. It must be a positive integer.
 136   - `taskStealing` (optional) - Task stealing enablement on idle.
 137   - `tasksStealingOnBackPressure` (optional) - Tasks stealing enablement under back pressure.
 138   - `tasksFinishedTimeout` (optional) - Queued tasks finished timeout in milliseconds at worker termination.
 139
 140   Default: `{ size: (pool maximum size)^2, concurrency: 1, taskStealing: true, tasksStealingOnBackPressure: true, tasksFinishedTimeout: 2000 }`
 141
 142 - `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.
 143
 144 - `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.
 145
 146 - `settings` (optional) - An object with the cluster settings. See [cluster](https://nodejs.org/api/cluster.html#cluster_cluster_settings) for more details.
 147
 148 ## Worker
 149
 150 ### `class YourWorker extends ThreadWorker/ClusterWorker`
 151
 152 `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.
 153 `opts` (optional) An object with these properties:
 154
 155 - `killBehavior` (optional) - Dictates if your worker will be deleted in case a task is active on it.
 156   **KillBehaviors.SOFT**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker **won't** be deleted.
 157   **KillBehaviors.HARD**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker will be deleted.
 158   This option only apply to the newly created workers.
 159   Default: `KillBehaviors.SOFT`
 160
 161 - `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.
 162   The last active time of your worker will be updated when it terminates a task.
 163   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.
 164   If `killBehavior` is set to `KillBehaviors.SOFT` your tasks have no timeout and your workers will not be terminated until your task is completed.
 165   Default: `60000`
 166
 167 - `killHandler` (optional) - A function that will be called when a worker is killed.
 168   Default: `() => {}`
 169
 170 #### `YourWorker.hasTaskFunction(name)`
 171
 172 `name` (mandatory) The task function name.
 173
 174 This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
 175
 176 #### `YourWorker.addTaskFunction(name, fn)`
 177
 178 `name` (mandatory) The task function name.
 179 `fn` (mandatory) The task function.
 180
 181 This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
 182
 183 #### `YourWorker.removeTaskFunction(name)`
 184
 185 `name` (mandatory) The task function name.
 186
 187 This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
 188
 189 #### `YourWorker.listTaskFunctionNames()`
 190
 191 This method is available on both worker implementations and returns an array of the task function names.
 192
 193 #### `YourWorker.setDefaultTaskFunction(name)`
 194
 195 `name` (mandatory) The task function name.
 196
 197 This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.