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   - [`PoolOptions`](#pooloptions)
  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 ### `PoolOptions`
  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   - `retries` (optional) - The number of retries to perform if no worker is eligible.
 115   - `measurement` (optional) - The measurement to use in worker choice strategies: `runTime`, `waitTime` or `elu`.
 116   - `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.
 117   - `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.
 118   - `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.
 119   - `weights` (optional) - The worker weights to use in weighted round robin worker choice strategies: `{ 0: 200, 1: 300, ..., n: 100 }`.
 120
 121   Default: `{ retries: 6, runTime: { median: false }, waitTime: { median: false }, elu: { median: false } }`
 122
 123 - `startWorkers` (optional) - Start the minimum number of workers at pool initialization.
 124   Default: `true`
 125 - `restartWorkerOnError` (optional) - Restart worker on uncaught error in this pool.
 126   Default: `true`
 127 - `enableEvents` (optional) - Events integrated with async resource emission enablement in this pool.
 128   Default: `true`
 129 - `enableTasksQueue` (optional) - Tasks queue per worker enablement in this pool.
 130   Default: `false`
 131
 132 - `tasksQueueOptions` (optional) - The worker tasks queue options object to use in this pool.
 133   Properties:
 134
 135   - `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.
 136   - `concurrency` (optional) - The maximum number of tasks that can be executed concurrently on a worker. It must be a positive integer.
 137   - `taskStealing` (optional) - Task stealing enablement on idle.
 138   - `tasksStealingOnBackPressure` (optional) - Tasks stealing enablement under back pressure.
 139   - `tasksFinishedTimeout` (optional) - Queued tasks finished timeout in milliseconds at worker termination.
 140
 141   Default: `{ size: (pool maximum size)^2, concurrency: 1, taskStealing: true, tasksStealingOnBackPressure: true, tasksFinishedTimeout: 1000 }`
 142
 143 - `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.
 144
 145 - `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.
 146
 147 - `settings` (optional) - An object with the cluster settings. See [cluster](https://nodejs.org/api/cluster.html#cluster_cluster_settings) for more details.
 148
 149 ## Worker
 150
 151 ### `class YourWorker extends ThreadWorker/ClusterWorker`
 152
 153 `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.
 154 `opts` (optional) An object with these properties:
 155
 156 - `killBehavior` (optional) - Dictates if your worker will be deleted in case a task is active on it.
 157   **KillBehaviors.SOFT**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker **won't** be deleted.
 158   **KillBehaviors.HARD**: If `currentTime - lastActiveTime` is greater than `maxInactiveTime` but a task is still executing or queued, then the worker will be deleted.
 159   This option only apply to the newly created workers.
 160   Default: `KillBehaviors.SOFT`
 161
 162 - `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.
 163   The last active time of your worker will be updated when it terminates a task.
 164   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.
 165   If `killBehavior` is set to `KillBehaviors.SOFT` your tasks have no timeout and your workers will not be terminated until your task is completed.
 166   Default: `60000`
 167
 168 - `killHandler` (optional) - A function that will be called when a worker is killed.
 169   Default: `() => {}`
 170
 171 #### `YourWorker.hasTaskFunction(name)`
 172
 173 `name` (mandatory) The task function name.
 174
 175 This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
 176
 177 #### `YourWorker.addTaskFunction(name, fn)`
 178
 179 `name` (mandatory) The task function name.
 180 `fn` (mandatory) The task function.
 181
 182 This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
 183
 184 #### `YourWorker.removeTaskFunction(name)`
 185
 186 `name` (mandatory) The task function name.
 187
 188 This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.
 189
 190 #### `YourWorker.listTaskFunctionNames()`
 191
 192 This method is available on both worker implementations and returns an array of the task function names.
 193
 194 #### `YourWorker.setDefaultTaskFunction(name)`
 195
 196 `name` (mandatory) The task function name.
 197
 198 This method is available on both worker implementations and returns `{ status: boolean, error?: Error }`.