Convert 'Testable' interface into an optional filter.

go/src/infra/gae/libs/gae/filters/featureBreaker/tq.go

Index: go/src/infra/gae/libs/gae/filters/featureBreaker/tq.go
diff --git a/go/src/infra/gae/libs/gae/filters/featureBreaker/tq.go b/go/src/infra/gae/libs/gae/filters/featureBreaker/tq.go
new file mode 100644
index 0000000000000000000000000000000000000000..34e4f80599e2d1e1b9d75bd326caba54b594506d
--- /dev/null
+++ b/go/src/infra/gae/libs/gae/filters/featureBreaker/tq.go
@@ -0,0 +1,91 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package featureBreaker
+
+import (
+	"golang.org/x/net/context"
+
+	"infra/gae/libs/gae"
+)
+
+type tqState struct {
+	*state
+
+	tq gae.TaskQueue
+}
+
+var _ gae.TaskQueue = (*tqState)(nil)
+
+func (t *tqState) Add(task *gae.TQTask, queueName string) (ret *gae.TQTask, err error) {
+	err = t.run(func() (err error) {
+		ret, err = t.tq.Add(task, queueName)
+		return
+	})
+	return
+}
+
+func (t *tqState) Delete(task *gae.TQTask, queueName string) error {
+	return t.run(func() error {
+		return t.tq.Delete(task, queueName)
+	})
+}
+
+func (t *tqState) AddMulti(tasks []*gae.TQTask, queueName string) (ret []*gae.TQTask, err error) {
+	err = t.run(func() (err error) {
+		ret, err = t.tq.AddMulti(tasks, queueName)
+		return
+	})
+	return
+}
+
+func (t *tqState) DeleteMulti(tasks []*gae.TQTask, queueName string) error {
+	return t.run(func() error {
+		return t.tq.DeleteMulti(tasks, queueName)
+	})
+}
+
+func (t *tqState) Lease(maxTasks int, queueName string, leaseTime int) (ret []*gae.TQTask, err error) {
+	err = t.run(func() (err error) {
+		ret, err = t.tq.Lease(maxTasks, queueName, leaseTime)
+		return
+	})
+	return
+}
+
+func (t *tqState) LeaseByTag(maxTasks int, queueName string, leaseTime int, tag string) (ret []*gae.TQTask, err error) {
+	err = t.run(func() (err error) {
+		ret, err = t.tq.LeaseByTag(maxTasks, queueName, leaseTime, tag)
+		return
+	})
+	return
+}
+
+func (t *tqState) ModifyLease(task *gae.TQTask, queueName string, leaseTime int) error {
+	return t.run(func() error {
+		return t.tq.ModifyLease(task, queueName, leaseTime)
+	})
+}
+
+func (t *tqState) Purge(queueName string) error {
+	return t.run(func() error {
+		return t.tq.Purge(queueName)
+	})
+}
+
+func (t *tqState) QueueStats(queueNames []string) (ret []gae.TQStatistics, err error) {
+	err = t.run(func() (err error) {
+		ret, err = t.tq.QueueStats(queueNames)
+		return
+	})
+	return
+}
+
+// FilterTQ installs a counter TaskQueue filter in the context.
+func FilterTQ(c context.Context, defaultError error) (context.Context, FeatureBreaker) {
+	state := newState(defaultError)
+	return gae.AddTQFilters(c, func(ic context.Context, tq gae.TaskQueue) gae.TaskQueue {
+		return &tqState{state, tq}
+	}), state
+}