mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
138 lines
3.6 KiB
Go
138 lines
3.6 KiB
Go
// Copyright 2015 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 command
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import (
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"bufio"
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"fmt"
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"os"
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"strings"
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"github.com/coreos/etcd/clientv3"
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"github.com/spf13/cobra"
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"golang.org/x/net/context"
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)
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var (
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watchRev int64
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watchPrefix bool
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watchInteractive bool
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watchPrevKey bool
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)
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// NewWatchCommand returns the cobra command for "watch".
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func NewWatchCommand() *cobra.Command {
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cmd := &cobra.Command{
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Use: "watch [options] [key or prefix] [range_end]",
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Short: "Watches events stream on keys or prefixes",
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Run: watchCommandFunc,
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}
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cmd.Flags().BoolVarP(&watchInteractive, "interactive", "i", false, "Interactive mode")
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cmd.Flags().BoolVar(&watchPrefix, "prefix", false, "Watch on a prefix if prefix is set")
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cmd.Flags().Int64Var(&watchRev, "rev", 0, "Revision to start watching")
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cmd.Flags().BoolVar(&watchPrevKey, "prev-kv", false, "get the previous key-value pair before the event happens")
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return cmd
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}
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// watchCommandFunc executes the "watch" command.
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func watchCommandFunc(cmd *cobra.Command, args []string) {
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if watchInteractive {
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watchInteractiveFunc(cmd, args)
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return
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}
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c := mustClientFromCmd(cmd)
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wc, err := getWatchChan(c, args)
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if err != nil {
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ExitWithError(ExitBadArgs, err)
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}
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printWatchCh(wc)
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if err = c.Close(); err != nil {
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ExitWithError(ExitBadConnection, err)
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}
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ExitWithError(ExitInterrupted, fmt.Errorf("watch is canceled by the server"))
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}
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func watchInteractiveFunc(cmd *cobra.Command, args []string) {
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c := mustClientFromCmd(cmd)
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reader := bufio.NewReader(os.Stdin)
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for {
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l, err := reader.ReadString('\n')
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if err != nil {
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ExitWithError(ExitInvalidInput, fmt.Errorf("Error reading watch request line: %v", err))
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}
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l = strings.TrimSuffix(l, "\n")
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args := argify(l)
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if len(args) < 2 {
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fmt.Fprintf(os.Stderr, "Invalid command %s (command type or key is not provided)\n", l)
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continue
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}
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if args[0] != "watch" {
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fmt.Fprintf(os.Stderr, "Invalid command %s (only support watch)\n", l)
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continue
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}
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flagset := NewWatchCommand().Flags()
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err = flagset.Parse(args[1:])
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if err != nil {
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fmt.Fprintf(os.Stderr, "Invalid command %s (%v)\n", l, err)
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continue
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}
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ch, err := getWatchChan(c, flagset.Args())
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if err != nil {
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fmt.Fprintf(os.Stderr, "Invalid command %s (%v)\n", l, err)
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continue
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}
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go printWatchCh(ch)
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}
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}
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func getWatchChan(c *clientv3.Client, args []string) (clientv3.WatchChan, error) {
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if len(args) < 1 || len(args) > 2 {
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return nil, fmt.Errorf("bad number of arguments")
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}
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key := args[0]
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opts := []clientv3.OpOption{clientv3.WithRev(watchRev)}
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if len(args) == 2 {
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if watchPrefix {
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return nil, fmt.Errorf("`range_end` and `--prefix` are mutually exclusive")
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}
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opts = append(opts, clientv3.WithRange(args[1]))
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}
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if watchPrefix {
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opts = append(opts, clientv3.WithPrefix())
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}
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if watchPrevKey {
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opts = append(opts, clientv3.WithPrevKV())
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}
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return c.Watch(context.TODO(), key, opts...), nil
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}
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func printWatchCh(ch clientv3.WatchChan) {
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for resp := range ch {
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if resp.Canceled {
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fmt.Fprintf(os.Stderr, "watch was canceled (%v)\n", resp.Err())
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}
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display.Watch(resp)
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}
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}
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