GoAwait
Package goawait is a simple module for asynchronous waiting. Use goawait when you need to wait for asynchronous tasks to complete before continuing normal execution.
GoAwait has functions that take a polling function and execute that function until it succeeds or the specified timeout is exceeded.
Example with polling function that returns an error:
ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond)
defer cancel()
poll := func(ctx context.Context) (interface{}, error) {
return nil, errors.New("error message")
}
if result != await.Func(ctx, 500*time.Microsecond, poll); result.Err != nil {
return result.Err
}Example simultaneously polling multiple functions:
ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond)
defer cancel()
poll1 := func(ctx context.Context) (interface{}, error) {
return "ok", nil
}
poll2 := func(ctx context.Context) (interface{}, error) {
return nil, fmt.Error("error message")
}
polls := map[string]goawait.PollFunc{"poll1": poll1, "poll2": poll2}
results := await.All(ctx, 200*time.Microsecond, polls)
for name, result := range results {
fmt.Println("Name:", name, "result:", result)
}Example polling until the first function returns:
faster := func(ctx context.Context) (interface{}, error) {
time.Sleep(time.Microsecond)
return "I'm fast", nil
}
slower := func(ctx context.Context) (interface{}, error) {
time.Sleep(time.Millisecond)
return "I'm slow", nil
}
polls := map[string]goawait.PollFunc{"faster": faster, "slower": slower}
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
result := await.First(ctx, time.Millisecond, polls)
if result.Err != nil {
log.Fatal(result.Err)
}
fmt.Prinln("First result:", result.Value)