mentalisttraceur/go-totaltimeout

totaltimeout

Spread one timeout over many operations.

Correctly and efficiently spreads one timeout over many steps by recalculating the time remaining after some amount of waiting has already happened, to pass an adjusted timeout to the next step.

Usually idiomatic Go code uses contexts, timers, or deadlines instead of timeouts - this helps dealing with code that doesn't.

Examples

Waiting in a "timed loop" for an API with retries (useful for unreliable APIs that may either hang or need retries):

timeout := totaltimeout.New(15 * time.Seconds)
for timeLeft := timeout.TimeLeft(); timeLeft > 0 {
    client := http.Client{Timeout: timeLeft}
    response, err := client.get("https://flaky.api.example.com")
    if err == nil && response.StatusCode == 200 {
        break
    }
}
// handle success or failure here, once all retries are done

Same as above, but with a wait between retries:

timeout := totaltimeout.New(15 * time.Seconds)
retryDelay := 2 * time.Seconds
for timeLeft := timeout.TimeLeft(); timeLeft > 0 {
    client := http.Client{Timeout: timeLeft}
    response, err := client.get("https://flaky.api.example.com")
    if err == nil && response.StatusCode == 200 {
        break
    }
    if timeout.TimeLeft() < retryDelay {
        break
    }
    time.Sleep(retryDelay)
}