1 files changed, 57 insertions, 0 deletions
diff --git a/vendor/github.com/matterbridge/slack/backoff.go b/vendor/github.com/matterbridge/slack/backoff.go
new file mode 100644
index 00000000..e555a1ad
--- /dev/null
+++ b/vendor/github.com/matterbridge/slack/backoff.go
@@ -0,0 +1,57 @@
+package slack
+
+import (
+	"math"
+	"math/rand"
+	"time"
+)
+
+// This one was ripped from https://github.com/jpillora/backoff/blob/master/backoff.go
+
+// Backoff 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().  Used in
+// conjunction with the time package.
+type backoff struct {
+	attempts int
+	//Factor is the multiplying factor for each increment step
+	Factor float64
+	//Jitter eases contention by randomizing backoff steps
+	Jitter bool
+	//Min and Max are the minimum and maximum values of the counter
+	Min, Max time.Duration
+}
+
+// Returns the current value of the counter and then multiplies it
+// Factor
+func (b *backoff) Duration() time.Duration {
+	//Zero-values are nonsensical, so we use
+	//them to apply defaults
+	if b.Min == 0 {
+		b.Min = 100 * time.Millisecond
+	}
+	if b.Max == 0 {
+		b.Max = 10 * time.Second
+	}
+	if b.Factor == 0 {
+		b.Factor = 2
+	}
+	//calculate this duration
+	dur := float64(b.Min) * math.Pow(b.Factor, float64(b.attempts))
+	if b.Jitter == true {
+		dur = rand.Float64()*(dur-float64(b.Min)) + float64(b.Min)
+	}
+	//cap!
+	if dur > float64(b.Max) {
+		return b.Max
+	}
+	//bump attempts count
+	b.attempts++
+	//return as a time.Duration
+	return time.Duration(dur)
+}
+
+//Resets the current value of the counter back to Min
+func (b *backoff) Reset() {
+	b.attempts = 0
+}