package monitor import ( "flag" "fmt" "sync" "github.com/hashicorp/consul/api" "github.com/hashicorp/consul/command/flags" "github.com/mitchellh/cli" ) // cmd is a Command implementation that queries a running // Consul agent what members are part of the cluster currently. type cmd struct { UI cli.Ui help string flags *flag.FlagSet http *flags.HTTPFlags shutdownCh <-chan struct{} lock sync.Mutex quitting bool // flags logLevel string logJSON bool } func New(ui cli.Ui, shutdownCh <-chan struct{}) *cmd { c := &cmd{UI: ui, shutdownCh: shutdownCh} c.init() return c } func (c *cmd) init() { c.flags = flag.NewFlagSet("", flag.ContinueOnError) c.flags.StringVar(&c.logLevel, "log-level", "INFO", "Log level of the agent.") c.flags.BoolVar(&c.logJSON, "log-json", false, "Output logs in JSON format.") c.http = &flags.HTTPFlags{} flags.Merge(c.flags, c.http.ClientFlags()) c.help = flags.Usage(help, c.flags) } func (c *cmd) Run(args []string) int { var logCh chan string var err error var client *api.Client if err = c.flags.Parse(args); err != nil { return 1 } client, err = c.http.APIClient() if err != nil { c.UI.Error(fmt.Sprintf("Error connecting to Consul agent: %s", err)) return 1 } eventDoneCh := make(chan struct{}) if c.logJSON { logCh, err = client.Agent().MonitorJSON(c.logLevel, eventDoneCh, nil) if err != nil { c.UI.Error(fmt.Sprintf("Error starting JSON monitor: %s", err)) return 1 } } logCh, err = client.Agent().Monitor(c.logLevel, eventDoneCh, nil) if err != nil { c.UI.Error(fmt.Sprintf("Error starting monitor: %s", err)) return 1 } go func() { defer close(eventDoneCh) OUTER: for { select { case log := <-logCh: if log == "" { break OUTER } c.UI.Info(log) } } c.lock.Lock() defer c.lock.Unlock() if !c.quitting { c.UI.Info("") c.UI.Output("Remote side ended the monitor! This usually means that the\n" + "remote side has exited or crashed.") } }() select { case <-eventDoneCh: return 1 case <-c.shutdownCh: c.lock.Lock() c.quitting = true c.lock.Unlock() } return 0 } func (c *cmd) Synopsis() string { return synopsis } func (c *cmd) Help() string { return c.help } const synopsis = "Stream logs from a Consul agent" const help = ` Usage: consul monitor [options] Shows recent log messages of a Consul agent, and attaches to the agent, outputting log messages as they occur in real time. The monitor lets you listen for log levels that may be filtered out of the Consul agent. For example your agent may only be logging at INFO level, but with the monitor you can see the DEBUG level logs. `