package command import ( "bytes" "encoding/json" "fmt" "os" "strconv" "strings" "github.com/hashicorp/consul/agent" "github.com/hashicorp/consul/watch" ) // WatchCommand is a Command implementation that is used to setup // a "watch" which uses a sub-process type WatchCommand struct { BaseCommand ShutdownCh <-chan struct{} } func (c *WatchCommand) Help() string { helpText := ` Usage: consul watch [options] [child...] Watches for changes in a given data view from Consul. If a child process is specified, it will be invoked with the latest results on changes. Otherwise, the latest values are dumped to stdout and the watch terminates. Providing the watch type is required, and other parameters may be required or supported depending on the watch type. ` + c.BaseCommand.Help() return strings.TrimSpace(helpText) } func (c *WatchCommand) Run(args []string) int { var watchType, key, prefix, service, tag, passingOnly, state, name string f := c.BaseCommand.NewFlagSet(c) f.StringVar(&watchType, "type", "", "Specifies the watch type. One of key, keyprefix, services, nodes, "+ "service, checks, or event.") f.StringVar(&key, "key", "", "Specifies the key to watch. Only for 'key' type.") f.StringVar(&prefix, "prefix", "", "Specifies the key prefix to watch. Only for 'keyprefix' type.") f.StringVar(&service, "service", "", "Specifies the service to watch. Required for 'service' type, "+ "optional for 'checks' type.") f.StringVar(&tag, "tag", "", "Specifies the service tag to filter on. Optional for 'service' type.") f.StringVar(&passingOnly, "passingonly", "", "Specifies if only hosts passing all checks are displayed. "+ "Optional for 'service' type, must be one of `[true|false]`. Defaults false.") f.StringVar(&state, "state", "", "Specifies the states to watch. Optional for 'checks' type.") f.StringVar(&name, "name", "", "Specifies an event name to watch. Only for 'event' type.") if err := c.BaseCommand.Parse(args); err != nil { return 1 } // Check for a type if watchType == "" { c.UI.Error("Watch type must be specified") c.UI.Error("") c.UI.Error(c.Help()) return 1 } // Grab the script to execute if any script := strings.Join(f.Args(), " ") // Compile the watch parameters params := make(map[string]interface{}) if watchType != "" { params["type"] = watchType } if c.BaseCommand.HTTPDatacenter() != "" { params["datacenter"] = c.BaseCommand.HTTPDatacenter() } if c.BaseCommand.HTTPToken() != "" { params["token"] = c.BaseCommand.HTTPToken() } if key != "" { params["key"] = key } if prefix != "" { params["prefix"] = prefix } if service != "" { params["service"] = service } if tag != "" { params["tag"] = tag } if c.BaseCommand.HTTPStale() { params["stale"] = c.BaseCommand.HTTPStale() } if state != "" { params["state"] = state } if name != "" { params["name"] = name } if passingOnly != "" { b, err := strconv.ParseBool(passingOnly) if err != nil { c.UI.Error(fmt.Sprintf("Failed to parse passingonly flag: %s", err)) return 1 } params["passingonly"] = b } // Create the watch wp, err := watch.Parse(params) if err != nil { c.UI.Error(fmt.Sprintf("%s", err)) return 1 } // Create and test the HTTP client client, err := c.BaseCommand.HTTPClient() if err != nil { c.UI.Error(fmt.Sprintf("Error connecting to Consul agent: %s", err)) return 1 } _, err = client.Agent().NodeName() if err != nil { c.UI.Error(fmt.Sprintf("Error querying Consul agent: %s", err)) return 1 } // Setup handler // errExit: // 0: false // 1: true errExit := 0 if script == "" { wp.Handler = func(idx uint64, data interface{}) { defer wp.Stop() buf, err := json.MarshalIndent(data, "", " ") if err != nil { c.UI.Error(fmt.Sprintf("Error encoding output: %s", err)) errExit = 1 } c.UI.Output(string(buf)) } } else { wp.Handler = func(idx uint64, data interface{}) { // Create the command var buf bytes.Buffer var err error cmd, err := agent.ExecScript(script) if err != nil { c.UI.Error(fmt.Sprintf("Error executing handler: %s", err)) goto ERR } cmd.Env = append(os.Environ(), "CONSUL_INDEX="+strconv.FormatUint(idx, 10), ) // Encode the input if err = json.NewEncoder(&buf).Encode(data); err != nil { c.UI.Error(fmt.Sprintf("Error encoding output: %s", err)) goto ERR } cmd.Stdin = &buf cmd.Stdout = os.Stdout cmd.Stderr = os.Stderr // Run the handler if err := cmd.Run(); err != nil { c.UI.Error(fmt.Sprintf("Error executing handler: %s", err)) goto ERR } return ERR: wp.Stop() errExit = 1 } } // Watch for a shutdown go func() { <-c.ShutdownCh wp.Stop() os.Exit(0) }() // Run the watch if err := wp.Run(c.BaseCommand.HTTPAddr()); err != nil { c.UI.Error(fmt.Sprintf("Error querying Consul agent: %s", err)) return 1 } return errExit } func (c *WatchCommand) Synopsis() string { return "Watch for changes in Consul" }