enable grpc retry
Change-Id: Id9f1cd18324e2788b2e6c4a9838ffff80ee49f0f
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/backoffutils/backoff.go b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/backoffutils/backoff.go
new file mode 100644
index 0000000..4e69a63
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/backoffutils/backoff.go
@@ -0,0 +1,28 @@
+// Copyright 2016 Michal Witkowski. All Rights Reserved.
+// See LICENSE for licensing terms.
+
+/*
+Backoff Helper Utilities
+
+Implements common backoff features.
+*/
+package backoffutils
+
+import (
+ "math/rand"
+ "time"
+)
+
+// JitterUp adds random jitter to the duration.
+//
+// This adds or subtracts time from the duration within a given jitter fraction.
+// For example for 10s and jitter 0.1, it will return a time within [9s, 11s])
+func JitterUp(duration time.Duration, jitter float64) time.Duration {
+ multiplier := jitter * (rand.Float64()*2 - 1)
+ return time.Duration(float64(duration) * (1 + multiplier))
+}
+
+// ExponentBase2 computes 2^(a-1) where a >= 1. If a is 0, the result is 0.
+func ExponentBase2(a uint) uint {
+ return (1 << a) >> 1
+}