Go: a context timeout stops waiting on a Sume job, not the job

A context.WithTimeout around your status calls ends your wait; the Sume job carries on and bills. Sume's docs say it plainly: a client-side timeout does not cancel the job, so you stopped the wait and nothing else. Store the job id before you wait, and on a deadline error log it and poll again later.

Three ways a wait can end

Keep the ending of the wait apart from the ending of the job. Only the last row below changes what Sume does.

The loop

The 3-second deadline in the sample is for demonstration; a video job needs minutes, and the docs call 20 minutes a reasonable client deadline for video. select waits for either the poll delay or the deadline, so the loop never sleeps past the context.

package main

import ("context"; "encoding/json"; "errors"; "fmt"; "net/http"; "os"; "time")
func main() {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second) // your patience, not the job's
	defer cancel()
	for {
		req, _ := http.NewRequestWithContext(ctx, "GET", os.Getenv("SUME_BASE")+"/v1/jobs/"+os.Args[1]+"/status", nil)
		req.Header.Set("Authorization", "Bearer "+os.Getenv("SUME_API_KEY"))
		res, err := http.DefaultClient.Do(req)
		if errors.Is(err, context.DeadlineExceeded) {
			fmt.Println("stopped waiting; the job keeps running and billing. Store its id.")
			return
		} else if err != nil {
			fmt.Println(err)
			return
		}
		var s struct{ Data struct{ Status string `json:"sume_status"`; Terminal bool } }
		json.NewDecoder(res.Body).Decode(&s)
		res.Body.Close()
		if s.Data.Terminal {
			fmt.Println(s.Data.Status)
			return
		}
		select {
		case <-time.After(2 * time.Second):
		case <-ctx.Done():
		}
	}
}

What it leaves undone

It does not cancel. If you want the job gone, call POST /v1/jobs/{id}/cancel, which succeeds only before generation starts and answers 409 afterwards. Cancelling a job that is already canceled returns the same job.

It also does not read next_poll_after_seconds; the fixed 2-second delay is fine for a demo and wrong for a long queue, where the server's hint is a minimum.