go-pool-of-workers

This is a simplistic Go implementation of the pool of workers [1].

When you might need it:

If you want to handle a number/stream of jobs in parallel but with a limited number of goroutines.

All you need is:

• a job Runner -- a handler for a specific unit of work
• an optional callback to handle a result of job

Code example:

type Job struct{ result SomeType }

func (r *Job) Run() {
    time.Sleep(200 * time.Millisecond)
    r.result = x
}

func main() {
    p := pool.NewPool(2, 4) // minWorkers, maxWorkers
    p.fnOnResult = func(handledJob Job) {}

    tasks := 10
    for tasksCnt > 0; tasksCnt-- {
        p.Submit(&Job{})
    }
    p.Stop()
}

Design

The key difference from canonical pool [2] is an absence of a common job queue. Instead, there is a common queue of idle workers [1][2].

Features / properties

• The producer (submitting a job) is unlocked as soon as a idle worker consumes the job, thus potentially reducing the time producer is blocked.
• Number of workers increases on demand from minWorkers to maxWorkers
• You may have as many types of jobs as you like

References

1. Go: Worker Pool vs Pool of Workers
2. Go by Example: Worker Pools
3. Handling 1 Million Requests per Minute with Go