1 import type { Worker
} from
'cluster'
2 import type { JSONValue
} from
'../../utility-types'
3 import type { ClusterPoolOptions
} from
'./fixed'
4 import { FixedClusterPool
} from
'./fixed'
7 * A cluster pool with a dynamic number of workers, but a guaranteed minimum number of workers.
9 * This cluster pool creates new workers when the others are busy, up to the maximum number of workers.
10 * When the maximum number of workers is reached, an event is emitted. If you want to listen to this event, use the pool's `emitter`.
12 * @template Data Type of data sent to the worker.
13 * @template Response Type of response of execution.
15 * @author [Christopher Quadflieg](https://github.com/Shinigami92)
18 export class DynamicClusterPool
<
19 Data
extends JSONValue
= JSONValue
,
20 Response
extends JSONValue
= JSONValue
21 > extends FixedClusterPool
<Data
, Response
> {
23 * Constructs a new poolifier dynamic cluster pool.
25 * @param min Minimum number of workers which are always active.
26 * @param max Maximum number of workers that can be created by this pool.
27 * @param filename Path to an implementation of a `ClusterWorker` file, which can be relative or absolute.
28 * @param opts Options for this fixed cluster pool. Default: `{ maxTasks: 1000 }`
32 public readonly max
: number,
34 opts
: ClusterPoolOptions
= { maxTasks
: 1000 }
36 super(min
, filename
, opts
)
40 * Choose a worker for the next task.
42 * It will first check for and return an idle worker.
43 * If all workers are busy, then it will try to create a new one up to the `max` worker count.
44 * If the max worker count is reached, the emitter will emit a `FullPool` event and it will fall back to using a round robin algorithm to distribute the load.
46 * @returns Cluster worker.
48 protected chooseWorker (): Worker
{
49 for (const [worker
, numberOfTasks
] of this.tasks
) {
50 if (numberOfTasks
=== 0) {
51 // A worker is free, use it
56 if (this.workers
.length
=== this.max
) {
57 this.emitter
.emit('FullPool')
58 return super.chooseWorker()
61 // All workers are busy, create a new worker
62 const worker
= this.createAndSetupWorker()
63 this.registerWorkerMessageListener
<Data
>(worker
, message
=> {
65 this.sendToWorker(worker
, { kill
: 1 })
66 void this.destroyWorker(worker
)