move retry to client-go

Kubernetes-commit: 7500b55ce42f82a405def05386e642ba661b2460

util/retry/BUILD

@@ -0,0 +1,40 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+    "go_test",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["util.go"],
+    deps = [
+        "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/wait:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["util_test.go"],
+    library = ":go_default_library",
+    deps = [
+        "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/wait:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+)

util/retry/OWNERS

@@ -0,0 +1,2 @@
+reviewers:
+- caesarxuchao

util/retry/util.go

@@ -0,0 +1,79 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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 retry
+
+import (
+	"time"
+
+	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/util/wait"
+)
+
+// DefaultRetry is the recommended retry for a conflict where multiple clients
+// are making changes to the same resource.
+var DefaultRetry = wait.Backoff{
+	Steps:    5,
+	Duration: 10 * time.Millisecond,
+	Factor:   1.0,
+	Jitter:   0.1,
+}
+
+// DefaultBackoff is the recommended backoff for a conflict where a client
+// may be attempting to make an unrelated modification to a resource under
+// active management by one or more controllers.
+var DefaultBackoff = wait.Backoff{
+	Steps:    4,
+	Duration: 10 * time.Millisecond,
+	Factor:   5.0,
+	Jitter:   0.1,
+}
+
+// RetryConflict executes the provided function repeatedly, retrying if the server returns a conflicting
+// write. Callers should preserve previous executions if they wish to retry changes. It performs an
+// exponential backoff.
+//
+//     var pod *api.Pod
+//     err := RetryOnConflict(DefaultBackoff, func() (err error) {
+//       pod, err = c.Pods("mynamespace").UpdateStatus(podStatus)
+//       return
+//     })
+//     if err != nil {
+//       // may be conflict if max retries were hit
+//       return err
+//     }
+//     ...
+//
+// TODO: Make Backoff an interface?
+func RetryOnConflict(backoff wait.Backoff, fn func() error) error {
+	var lastConflictErr error
+	err := wait.ExponentialBackoff(backoff, func() (bool, error) {
+		err := fn()
+		switch {
+		case err == nil:
+			return true, nil
+		case errors.IsConflict(err):
+			lastConflictErr = err
+			return false, nil
+		default:
+			return false, err
+		}
+	})
+	if err == wait.ErrWaitTimeout {
+		err = lastConflictErr
+	}
+	return err
+}

util/retry/util_test.go

@@ -0,0 +1,71 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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 retry
+
+import (
+	"fmt"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/wait"
+)
+
+func TestRetryOnConflict(t *testing.T) {
+	opts := wait.Backoff{Factor: 1.0, Steps: 3}
+	conflictErr := errors.NewConflict(schema.GroupResource{Resource: "test"}, "other", nil)
+
+	// never returns
+	err := RetryOnConflict(opts, func() error {
+		return conflictErr
+	})
+	if err != conflictErr {
+		t.Errorf("unexpected error: %v", err)
+	}
+
+	// returns immediately
+	i := 0
+	err = RetryOnConflict(opts, func() error {
+		i++
+		return nil
+	})
+	if err != nil || i != 1 {
+		t.Errorf("unexpected error: %v", err)
+	}
+
+	// returns immediately on error
+	testErr := fmt.Errorf("some other error")
+	err = RetryOnConflict(opts, func() error {
+		return testErr
+	})
+	if err != testErr {
+		t.Errorf("unexpected error: %v", err)
+	}
+
+	// keeps retrying
+	i = 0
+	err = RetryOnConflict(opts, func() error {
+		if i < 2 {
+			i++
+			return errors.NewConflict(schema.GroupResource{Resource: "test"}, "other", nil)
+		}
+		return nil
+	})
+	if err != nil || i != 2 {
+		t.Errorf("unexpected error: %v", err)
+	}
+}