diff --git a/clientv3/ordering/doc.go b/clientv3/ordering/doc.go new file mode 100644 index 000000000..856f33058 --- /dev/null +++ b/clientv3/ordering/doc.go @@ -0,0 +1,42 @@ +// Copyright 2017 The etcd 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 ordering is a clientv3 wrapper that caches response header revisions +// to detect ordering violations from stale responses. Users may define a +// policy on how to handle the ordering violation, but typically the client +// should connect to another endpoint and reissue the request. +// +// The most common situation where an ordering violation happens is a client +// reconnects to a partitioned member and issues a serializable read. Since the +// partitioned member is likely behind the last member, it may return a Get +// response based on a store revision older than the store revision used to +// service a prior Get on the former endpoint. +// +// First, create a client: +// +// cli, err := clientv3.New(clientv3.Config{Endpoints: []string{"localhost:2379"}}) +// if err != nil { +// // handle error! +// } +// +// Next, override the client interface with the ordering wrapper: +// +// vf := func(op clientv3.Op, resp clientv3.OpResponse, prevRev int64) error { +// return fmt.Errorf("ordering: issued %+v, got %+v, expected rev=%v", op, resp, prevRev) +// } +// cli.KV = ordering.NewKV(cli.KV, vf) +// +// Now calls using 'cli' will reject order violations with an error. +// +package ordering diff --git a/clientv3/ordering/kv.go b/clientv3/ordering/kv.go index e8bf07b8c..0001ce013 100644 --- a/clientv3/ordering/kv.go +++ b/clientv3/ordering/kv.go @@ -15,10 +15,10 @@ package ordering import ( - "context" "sync" "github.com/coreos/etcd/clientv3" + "golang.org/x/net/context" ) // kvOrdering ensures that serialized requests do not return