Add upload to Google Cloud Storage and Google Compute Image creation

- the image upload uses the cloud API
- currently auth and image creation need the `gcloud` CLI tool.

Signed-off-by: Justin Cormack <justin.cormack@docker.com>

vendor/github.com/googleapis/gax-go/invoke.go

@@ -0,0 +1,90 @@
+// 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 (
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+// A user defined call stub.
+type APICall func(context.Context) error
+
+// Invoke calls the given APICall,
+// performing retries as specified by opts, if any.
+func Invoke(ctx context.Context, call APICall, opts ...CallOption) error {
+	var settings CallSettings
+	for _, opt := range opts {
+		opt.Resolve(&settings)
+	}
+	return invoke(ctx, call, settings, Sleep)
+}
+
+// Sleep is similar to time.Sleep, but it can be interrupted by ctx.Done() closing.
+// If interrupted, Sleep returns ctx.Err().
+func Sleep(ctx context.Context, d time.Duration) error {
+	t := time.NewTimer(d)
+	select {
+	case <-ctx.Done():
+		t.Stop()
+		return ctx.Err()
+	case <-t.C:
+		return nil
+	}
+}
+
+type sleeper func(ctx context.Context, d time.Duration) error
+
+// invoke implements Invoke, taking an additional sleeper argument for testing.
+func invoke(ctx context.Context, call APICall, settings CallSettings, sp sleeper) error {
+	var retryer Retryer
+	for {
+		err := call(ctx)
+		if err == nil {
+			return nil
+		}
+		if settings.Retry == nil {
+			return err
+		}
+		if retryer == nil {
+			if r := settings.Retry(); r != nil {
+				retryer = r
+			} else {
+				return err
+			}
+		}
+		if d, ok := retryer.Retry(err); !ok {
+			return err
+		} else if err = sp(ctx, d); err != nil {
+			return err
+		}
+	}
+}