2aa18cafc6
With CoreDNS now supporting etcdv3 as the DNS backend, we can update our federation target to etcdv3. Users will now be able to use etcdv3 server as the federation backbone. Minio will update bucket data to etcdv3 and CoreDNS can pick that data up and serve it as bucket style DNS path.
106 lines
3.6 KiB
Go
106 lines
3.6 KiB
Go
// Copyright 2016 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package clientv3 implements the official Go etcd client for v3.
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//
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// Create client using `clientv3.New`:
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//
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// // expect dial time-out on ipv4 blackhole
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// _, err := clientv3.New(clientv3.Config{
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// Endpoints: []string{"http://254.0.0.1:12345"},
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// DialTimeout: 2 * time.Second
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// })
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//
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// // etcd clientv3 >= v3.2.10, grpc/grpc-go >= v1.7.3
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// if err == context.DeadlineExceeded {
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// // handle errors
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// }
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//
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// // etcd clientv3 <= v3.2.9, grpc/grpc-go <= v1.2.1
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// if err == grpc.ErrClientConnTimeout {
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// // handle errors
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// }
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//
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// cli, err := clientv3.New(clientv3.Config{
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// Endpoints: []string{"localhost:2379", "localhost:22379", "localhost:32379"},
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// DialTimeout: 5 * time.Second,
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// })
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// if err != nil {
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// // handle error!
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// }
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// defer cli.Close()
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//
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// Make sure to close the client after using it. If the client is not closed, the
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// connection will have leaky goroutines.
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//
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// To specify a client request timeout, wrap the context with context.WithTimeout:
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//
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// ctx, cancel := context.WithTimeout(context.Background(), timeout)
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// resp, err := kvc.Put(ctx, "sample_key", "sample_value")
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// cancel()
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// if err != nil {
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// // handle error!
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// }
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// // use the response
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//
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// The Client has internal state (watchers and leases), so Clients should be reused instead of created as needed.
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// Clients are safe for concurrent use by multiple goroutines.
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//
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// etcd client returns 3 types of errors:
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//
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// 1. context error: canceled or deadline exceeded.
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// 2. gRPC status error: e.g. when clock drifts in server-side before client's context deadline exceeded.
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// 3. gRPC error: see https://github.com/coreos/etcd/blob/master/etcdserver/api/v3rpc/rpctypes/error.go
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//
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// Here is the example code to handle client errors:
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//
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// resp, err := kvc.Put(ctx, "", "")
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// if err != nil {
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// if err == context.Canceled {
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// // ctx is canceled by another routine
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// } else if err == context.DeadlineExceeded {
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// // ctx is attached with a deadline and it exceeded
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// } else if ev, ok := status.FromError(err); ok {
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// code := ev.Code()
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// if code == codes.DeadlineExceeded {
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// // server-side context might have timed-out first (due to clock skew)
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// // while original client-side context is not timed-out yet
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// }
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// } else if verr, ok := err.(*v3rpc.ErrEmptyKey); ok {
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// // process (verr.Errors)
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// } else {
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// // bad cluster endpoints, which are not etcd servers
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// }
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// }
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//
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// go func() { cli.Close() }()
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// _, err := kvc.Get(ctx, "a")
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// if err != nil {
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// // with etcd clientv3 <= v3.3
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// if err == context.Canceled {
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// // grpc balancer calls 'Get' with an inflight client.Close
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// } else if err == grpc.ErrClientConnClosing {
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// // grpc balancer calls 'Get' after client.Close.
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// }
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// // with etcd clientv3 >= v3.4
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// if clientv3.IsConnCanceled(err) {
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// // gRPC client connection is closed
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// }
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// }
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//
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// The grpc load balancer is registered statically and is shared across etcd clients.
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// To enable detailed load balancer logging, set the ETCD_CLIENT_DEBUG environment
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// variable. E.g. "ETCD_CLIENT_DEBUG=1".
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//
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package clientv3
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