package main import ( "fmt" "strings" "time" "github.com/hpcloud/tail" "github.com/pkg/errors" "github.com/projectatomic/libpod/libpod" "github.com/urfave/cli" ) type logOptions struct { details bool follow bool sinceTime time.Time tail uint64 } var ( logsFlags = []cli.Flag{ cli.BoolFlag{ Name: "details", Usage: "Show extra details provided to the logs", Hidden: true, }, cli.BoolFlag{ Name: "follow, f", Usage: "Follow log output. The default is false", }, cli.StringFlag{ Name: "since", Usage: "Show logs since TIMESTAMP", }, cli.Uint64Flag{ Name: "tail", Usage: "Output the specified number of LINES at the end of the logs. Defaults to 0, which prints all lines", }, } logsDescription = "The kpod logs command batch-retrieves whatever logs are present for a container at the time of execution. This does not guarantee execution" + "order when combined with kpod run (i.e. your run may not have generated any logs at the time you execute kpod logs" logsCommand = cli.Command{ Name: "logs", Usage: "Fetch the logs of a container", Description: logsDescription, Flags: logsFlags, Action: logsCmd, ArgsUsage: "CONTAINER", } ) func logsCmd(c *cli.Context) error { if err := validateFlags(c, logsFlags); err != nil { return err } runtime, err := getRuntime(c) if err != nil { return errors.Wrapf(err, "could not get runtime") } defer runtime.Shutdown(false) args := c.Args() if len(args) != 1 { return errors.Errorf("'kpod logs' requires exactly one container name/ID") } sinceTime := time.Time{} if c.IsSet("since") { // parse time, error out if something is wrong since, err := time.Parse("2006-01-02T15:04:05.999999999-07:00", c.String("since")) if err != nil { return errors.Wrapf(err, "could not parse time: %q", c.String("since")) } sinceTime = since } opts := logOptions{ details: c.Bool("details"), follow: c.Bool("follow"), sinceTime: sinceTime, tail: c.Uint64("tail"), } ctr, err := runtime.LookupContainer(args[0]) if err != nil { return err } logs := make(chan string) go func() { err = getLogs(ctr, logs, opts) }() printLogs(logs) return err } // getLogs returns the logs of a container from the log file // log file is created when the container is started/ran func getLogs(container *libpod.Container, logChan chan string, opts logOptions) error { defer close(logChan) seekInfo := &tail.SeekInfo{Offset: 0, Whence: 0} if opts.tail > 0 { // seek to correct position in log files seekInfo.Offset = int64(opts.tail) seekInfo.Whence = 2 } t, err := tail.TailFile(container.LogPath(), tail.Config{Follow: opts.follow, ReOpen: false, Location: seekInfo}) for line := range t.Lines { if since, err := logSinceTime(opts.sinceTime, line.Text); err != nil || !since { continue } logMessage := line.Text[secondSpaceIndex(line.Text):] logChan <- logMessage } return err } func printLogs(logs chan string) { for line := range logs { fmt.Println(line) } } // returns true if the time stamps of the logs are equal to or after the // timestamp comparing to func logSinceTime(sinceTime time.Time, logStr string) (bool, error) { timestamp := strings.Split(logStr, " ")[0] logTime, err := time.Parse("2006-01-02T15:04:05.999999999-07:00", timestamp) if err != nil { return false, err } return logTime.After(sinceTime) || logTime.Equal(sinceTime), nil } // secondSpaceIndex returns the index of the second space in a string // In a line of the logs, the first two tokens are a timestamp and stdout/stderr, // followed by the message itself. This allows us to get the index of the message // and avoid sending the other information back to the caller of GetLogs() func secondSpaceIndex(line string) int { index := strings.Index(line, " ") if index == -1 { return 0 } index = strings.Index(line[index:], " ") if index == -1 { return 0 } return index }