35 lines
885 B
Go
35 lines
885 B
Go
|
package slowmessage
|
||
|
|
|
||
|
|
import (
|
||
|
|
"time"
|
||
|
|
)
|
||
|
|
|
||
|
|
// SlowFunc is the function that could be slow. Usually, you'll have to
|
||
|
|
// wrap an existing function in a lambda to make it match this type signature.
|
||
|
|
type SlowFunc func() error
|
||
|
|
|
||
|
|
// CallbackFunc is the function that is triggered when the threshold is reached.
|
||
|
|
type CallbackFunc func()
|
||
|
|
|
||
|
|
// Do calls sf. If threshold time has passed, cb is called. Note that this
|
||
|
|
// call will be made concurrently to sf still running.
|
||
|
|
func Do(threshold time.Duration, sf SlowFunc, cb CallbackFunc) error {
|
||
|
|
// Call the slow function
|
||
|
|
errCh := make(chan error, 1)
|
||
|
|
go func() {
|
||
|
|
errCh <- sf()
|
||
|
|
}()
|
||
|
|
|
||
|
|
// Wait for it to complete or the threshold to pass
|
||
|
|
select {
|
||
|
|
case err := <-errCh:
|
||
|
|
return err
|
||
|
|
case <-time.After(threshold):
|
||
|
|
// Threshold reached, call the callback
|
||
|
|
cb()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Wait an indefinite amount of time for it to finally complete
|
||
|
|
return <-errCh
|
||
|
|
}
|