Simple backoff algorithm in Go (golang)
A simple exponential backoff counter in Go (Golang)
$ go get -v github.com/jpillora/backoffBackoff is a time.Duration counter. It starts at Min. After every call to Duration() it is multiplied by Factor. It is capped at Max. It returns to Min on every call to Reset(). Jitter adds randomness (see below). Used in conjunction with the time package.
b := &backoff.Backoff{
//These are the defaults
Min: 100 * time.Millisecond,
Max: 10 * time.Second,
Factor: 2,
Jitter: false,
}
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("Reset!\n")
b.Reset()
fmt.Printf("%s\n", b.Duration())100ms
200ms
400ms
Reset!
100msnet packageb := &backoff.Backoff{
Max: 5 * time.Minute,
}
for {
conn, err := net.Dial("tcp", "example.com:5309")
if err != nil {
d := b.Duration()
fmt.Printf("%s, reconnecting in %s", err, d)
time.Sleep(d)
continue
}
//connected
b.Reset()
conn.Write([]byte("hello world!"))
// ... Read ... Write ... etc
conn.Close()
//disconnected
}
JitterEnabling Jitter adds some randomization to the backoff durations. See Amazon's writeup of performance gains using jitter. Seeding is not necessary but doing so gives repeatable results.
import "math/rand"
b := &backoff.Backoff{
Jitter: true,
}
rand.Seed(42)
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("Reset!\n")
b.Reset()
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())100ms
106.600049ms
281.228155ms
Reset!
100ms
104.381845ms
214.957989mshttps://godoc.org/github.com/jpillora/backoff
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