mirror of https://github.com/pulumi/pulumi.git
86 lines
2.5 KiB
Go
86 lines
2.5 KiB
Go
// Copyright 2016-2017, Pulumi Corporation. All rights reserved.
|
|
|
|
package retry
|
|
|
|
import (
|
|
"context"
|
|
"time"
|
|
)
|
|
|
|
type Acceptor struct {
|
|
Accept Acceptance // a function that determines when to proceed.
|
|
Progress Progress // an optional progress function.
|
|
Delay *time.Duration // an optional delay duration.
|
|
Backoff *float64 // an optional backoff multiplier.
|
|
}
|
|
|
|
type Progress func(int) bool
|
|
|
|
const (
|
|
DefaultDelay time.Duration = 250 * time.Millisecond // by default, delay by 250ms
|
|
DefaultBackoff float64 = 2.0 // by default, backoff by 2.0
|
|
)
|
|
|
|
type Acceptance func() (bool, error)
|
|
|
|
// Until waits until the acceptor accepts the current condition, or the context expires, whichever comes first. A
|
|
// return boolean of true means the acceptor eventually accepted; a non-nil error means the acceptor returned an error.
|
|
// If an acceptor accepts a condition after the context has expired, we ignore the expiration and return the condition.
|
|
func Until(ctx context.Context, acceptor Acceptor) (bool, error) {
|
|
expired := false
|
|
|
|
// Prepare our delay and backoff variables.
|
|
var delay time.Duration
|
|
if acceptor.Delay == nil {
|
|
delay = DefaultDelay
|
|
} else {
|
|
delay = *acceptor.Delay
|
|
}
|
|
var backoff float64
|
|
if acceptor.Backoff == nil {
|
|
backoff = DefaultBackoff
|
|
} else {
|
|
backoff = *acceptor.Backoff
|
|
}
|
|
|
|
// If the context expires before the waiter has accepted, return.
|
|
go func() {
|
|
<-ctx.Done()
|
|
expired = true
|
|
}()
|
|
|
|
// Loop until the condition is accepted, or the context expires, whichever comes first.
|
|
tries := 1
|
|
for !expired {
|
|
if b, err := acceptor.Accept(); b || err != nil {
|
|
return b, err
|
|
}
|
|
if acceptor.Progress != nil && !acceptor.Progress(tries) {
|
|
break // progress function asked to quit.
|
|
}
|
|
time.Sleep(delay)
|
|
delay = time.Duration(float64(delay) * backoff)
|
|
tries++
|
|
}
|
|
|
|
return false, nil
|
|
}
|
|
|
|
// UntilDeadline creates a child context with the given deadline, and then invokes the above Until function.
|
|
func UntilDeadline(ctx context.Context, acceptor Acceptor, deadline time.Time) (bool, error) {
|
|
var cancel context.CancelFunc
|
|
ctx, cancel = context.WithDeadline(ctx, deadline)
|
|
b, err := Until(ctx, acceptor)
|
|
cancel()
|
|
return b, err
|
|
}
|
|
|
|
// UntilTimeout creates a child context with the given timeout, and then invokes the above Until function.
|
|
func UntilTimeout(ctx context.Context, acceptor Acceptor, timeout time.Duration) (bool, error) {
|
|
var cancel context.CancelFunc
|
|
ctx, cancel = context.WithTimeout(ctx, timeout)
|
|
b, err := Until(ctx, acceptor)
|
|
cancel()
|
|
return b, err
|
|
}
|