1 files changed, 136 insertions, 0 deletions
diff --git a/vendor/github.com/googleapis/gax-go/call_option.go b/vendor/github.com/googleapis/gax-go/call_option.go
new file mode 100644
index 0000000..4ba1cdf
--- /dev/null
+++ b/vendor/github.com/googleapis/gax-go/call_option.go
@@ -0,0 +1,136 @@
+// Copyright 2016, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package gax
+
+import (
+	"math/rand"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+)
+
+// CallOption is an option used by Invoke to control behaviors of RPC calls.
+// CallOption works by modifying relevant fields of CallSettings.
+type CallOption interface {
+	// Resolve applies the option by modifying cs.
+	Resolve(cs *CallSettings)
+}
+
+// Retryer is used by Invoke to determine retry behavior.
+type Retryer interface {
+	// Retry reports whether a request should be retriedand how long to pause before retrying
+	// if the previous attempt returned with err. Invoke never calls Retry with nil error.
+	Retry(err error) (pause time.Duration, shouldRetry bool)
+}
+
+type retryerOption func() Retryer
+
+func (o retryerOption) Resolve(s *CallSettings) {
+	s.Retry = o
+}
+
+// WithRetry sets CallSettings.Retry to fn.
+func WithRetry(fn func() Retryer) CallOption {
+	return retryerOption(fn)
+}
+
+// OnCodes returns a Retryer that retries if and only if
+// the previous attempt returns a GRPC error whose error code is stored in cc.
+// Pause times between retries are specified by bo.
+//
+// bo is only used for its parameters; each Retryer has its own copy.
+func OnCodes(cc []codes.Code, bo Backoff) Retryer {
+	return &boRetryer{
+		backoff: bo,
+		codes:   append([]codes.Code(nil), cc...),
+	}
+}
+
+type boRetryer struct {
+	backoff Backoff
+	codes   []codes.Code
+}
+
+func (r *boRetryer) Retry(err error) (time.Duration, bool) {
+	c := grpc.Code(err)
+	for _, rc := range r.codes {
+		if c == rc {
+			return r.backoff.Pause(), true
+		}
+	}
+	return 0, false
+}
+
+// Backoff implements exponential backoff.
+// The wait time between retries is a random value between 0 and the "retry envelope".
+// The envelope starts at Initial and increases by the factor of Multiplier every retry,
+// but is capped at Max.
+type Backoff struct {
+	// Initial is the initial value of the retry envelope, defaults to 1 second.
+	Initial time.Duration
+
+	// Max is the maximum value of the retry envelope, defaults to 30 seconds.
+	Max time.Duration
+
+	// Multiplier is the factor by which the retry envelope increases.
+	// It should be greater than 1 and defaults to 2.
+	Multiplier float64
+
+	// cur is the current retry envelope
+	cur time.Duration
+}
+
+func (bo *Backoff) Pause() time.Duration {
+	if bo.Initial == 0 {
+		bo.Initial = time.Second
+	}
+	if bo.cur == 0 {
+		bo.cur = bo.Initial
+	}
+	if bo.Max == 0 {
+		bo.Max = 30 * time.Second
+	}
+	if bo.Multiplier < 1 {
+		bo.Multiplier = 2
+	}
+	d := time.Duration(rand.Int63n(int64(bo.cur)))
+	bo.cur = time.Duration(float64(bo.cur) * bo.Multiplier)
+	if bo.cur > bo.Max {
+		bo.cur = bo.Max
+	}
+	return d
+}
+
+type CallSettings struct {
+	// Retry returns a Retryer to be used to control retry logic of a method call.
+	// If Retry is nil or the returned Retryer is nil, the call will not be retried.
+	Retry func() Retryer
+}