1 files changed, 84 insertions, 0 deletions

diff --git a/vendor/google.golang.org/api/gensupport/retry.go b/vendor/google.golang.org/api/gensupport/retry.go
new file mode 100644
index 0000000..fdde3f4
--- /dev/null
+++ b/vendor/google.golang.org/api/gensupport/retry.go
@@ -0,0 +1,84 @@
+// Copyright 2017 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gensupport
+
+import (
+        "context"
+        "io"
+        "net"
+        "net/http"
+        "time"
+)
+
+// Retry invokes the given function, retrying it multiple times if the connection failed or
+// the HTTP status response indicates the request should be attempted again. ctx may be nil.
+func Retry(ctx context.Context, f func() (*http.Response, error), backoff BackoffStrategy) (*http.Response, error) {
+        for {
+                resp, err := f()
+
+                var status int
+                if resp != nil {
+                        status = resp.StatusCode
+                }
+
+                // Return if we shouldn't retry.
+                pause, retry := backoff.Pause()
+                if !shouldRetry(status, err) || !retry {
+                        return resp, err
+                }
+
+                // Ensure the response body is closed, if any.
+                if resp != nil && resp.Body != nil {
+                        resp.Body.Close()
+                }
+
+                // Pause, but still listen to ctx.Done if context is not nil.
+                var done <-chan struct{}
+                if ctx != nil {
+                        done = ctx.Done()
+                }
+                select {
+                case <-done:
+                        return nil, ctx.Err()
+                case <-time.After(pause):
+                }
+        }
+}
+
+// DefaultBackoffStrategy returns a default strategy to use for retrying failed upload requests.
+func DefaultBackoffStrategy() BackoffStrategy {
+        return &ExponentialBackoff{
+                Base: 250 * time.Millisecond,
+                Max:  16 * time.Second,
+        }
+}
+
+// shouldRetry returns true if the HTTP response / error indicates that the
+// request should be attempted again.
+func shouldRetry(status int, err error) bool {
+        if 500 <= status && status <= 599 {
+                return true
+        }
+        if status == statusTooManyRequests {
+                return true
+        }
+        if err == io.ErrUnexpectedEOF {
+                return true
+        }
+        if err, ok := err.(net.Error); ok {
+                return err.Temporary()
+        }
+        return false
+}