1 files changed, 153 insertions, 0 deletions
diff --git a/cmd/podman/logs.go b/cmd/podman/logs.go
new file mode 100644
index 000000000..8745d5d7f
--- /dev/null
+++ b/cmd/podman/logs.go
@@ -0,0 +1,153 @@
+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 podman 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 podman run (i.e. your run may not have generated any logs at the time you execute podman 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("'podman 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
+}