Vendor main dependencies.

vendor/google.golang.org/api/gensupport/retry.go

@@ -0,0 +1,77 @@
+package gensupport
+
+import (
+	"io"
+	"net"
+	"net/http"
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+// 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 {
+	// Retry for 5xx response codes.
+	if 500 <= status && status < 600 {
+		return true
+	}
+
+	// Retry on statusTooManyRequests{
+	if status == statusTooManyRequests {
+		return true
+	}
+
+	// Retry on unexpected EOFs and temporary network errors.
+	if err == io.ErrUnexpectedEOF {
+		return true
+	}
+	if err, ok := err.(net.Error); ok {
+		return err.Temporary()
+	}
+
+	return false
+}