| // Copyright 2015 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 command |
| |
| import ( |
| "context" |
| "errors" |
| "fmt" |
| "os" |
| "os/exec" |
| "os/signal" |
| |
| "github.com/coreos/etcd/client" |
| |
| "github.com/urfave/cli" |
| ) |
| |
| // NewExecWatchCommand returns the CLI command for "exec-watch". |
| func NewExecWatchCommand() cli.Command { |
| return cli.Command{ |
| Name: "exec-watch", |
| Usage: "watch a key for changes and exec an executable", |
| ArgsUsage: "<key> <command> [args...]", |
| Flags: []cli.Flag{ |
| cli.IntFlag{Name: "after-index", Value: 0, Usage: "watch after the given index"}, |
| cli.BoolFlag{Name: "recursive, r", Usage: "watch all values for key and child keys"}, |
| }, |
| Action: func(c *cli.Context) error { |
| execWatchCommandFunc(c, mustNewKeyAPI(c)) |
| return nil |
| }, |
| } |
| } |
| |
| // execWatchCommandFunc executes the "exec-watch" command. |
| func execWatchCommandFunc(c *cli.Context, ki client.KeysAPI) { |
| args := c.Args() |
| argslen := len(args) |
| |
| if argslen < 2 { |
| handleError(c, ExitBadArgs, errors.New("key and command to exec required")) |
| } |
| |
| var ( |
| key string |
| cmdArgs []string |
| ) |
| |
| foundSep := false |
| for i := range args { |
| if args[i] == "--" && i != 0 { |
| foundSep = true |
| break |
| } |
| } |
| |
| if foundSep { |
| key = args[0] |
| cmdArgs = args[2:] |
| } else { |
| // If no flag is parsed, the order of key and cmdArgs will be switched and |
| // args will not contain `--`. |
| key = args[argslen-1] |
| cmdArgs = args[:argslen-1] |
| } |
| |
| index := 0 |
| if c.Int("after-index") != 0 { |
| index = c.Int("after-index") |
| } |
| |
| recursive := c.Bool("recursive") |
| |
| sigch := make(chan os.Signal, 1) |
| signal.Notify(sigch, os.Interrupt) |
| |
| go func() { |
| <-sigch |
| os.Exit(0) |
| }() |
| |
| w := ki.Watcher(key, &client.WatcherOptions{AfterIndex: uint64(index), Recursive: recursive}) |
| |
| for { |
| resp, err := w.Next(context.TODO()) |
| if err != nil { |
| handleError(c, ExitServerError, err) |
| } |
| if resp.Node.Dir { |
| fmt.Fprintf(os.Stderr, "Ignored dir %s change\n", resp.Node.Key) |
| continue |
| } |
| |
| cmd := exec.Command(cmdArgs[0], cmdArgs[1:]...) |
| cmd.Env = environResponse(resp, os.Environ()) |
| |
| cmd.Stdout = os.Stdout |
| cmd.Stderr = os.Stderr |
| |
| go func() { |
| err := cmd.Start() |
| if err != nil { |
| fmt.Fprintf(os.Stderr, err.Error()) |
| os.Exit(1) |
| } |
| cmd.Wait() |
| }() |
| } |
| } |
| |
| func environResponse(resp *client.Response, env []string) []string { |
| env = append(env, "ETCD_WATCH_ACTION="+resp.Action) |
| env = append(env, "ETCD_WATCH_MODIFIED_INDEX="+fmt.Sprintf("%d", resp.Node.ModifiedIndex)) |
| env = append(env, "ETCD_WATCH_KEY="+resp.Node.Key) |
| env = append(env, "ETCD_WATCH_VALUE="+resp.Node.Value) |
| return env |
| } |