kube: Add support for podman pod logs

Following PR adds support for `kubectl` like `pod logs` to podman.
Usage `podman pod logs <podIDorName` gives a stream of logs for all
the containers within the pod with **containername** as a field.

Just like **`kubectl`** also supports `podman pod logs -c ctrIDorName podIDorName`
to limit the log stream to any of the specificied container which belongs to pod.

Signed-off-by: Aditya Rajan <arajan@redhat.com>

1 files changed, 140 insertions, 0 deletions

diff --git a/cmd/podman/pods/logs.go b/cmd/podman/pods/logs.go
new file mode 100644
index 000000000..fe5205669
--- /dev/null
+++ b/cmd/podman/pods/logs.go
@@ -0,0 +1,140 @@
+package pods
+
+import (
+	"os"
+
+	"github.com/containers/common/pkg/completion"
+	"github.com/containers/podman/v3/cmd/podman/common"
+	"github.com/containers/podman/v3/cmd/podman/registry"
+	"github.com/containers/podman/v3/cmd/podman/validate"
+	"github.com/containers/podman/v3/libpod/define"
+	"github.com/containers/podman/v3/pkg/domain/entities"
+	"github.com/containers/podman/v3/pkg/util"
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+)
+
+// logsOptionsWrapper wraps entities.LogsOptions and prevents leaking
+// CLI-only fields into the API types.
+type logsOptionsWrapper struct {
+	entities.PodLogsOptions
+
+	SinceRaw string
+
+	UntilRaw string
+}
+
+var (
+	logsPodOptions     logsOptionsWrapper
+	logsPodDescription = `Displays logs for pod with one or more containers.`
+	logsPodCommand     = &cobra.Command{
+		Use:   "logs [options] POD",
+		Short: "Fetch logs for pod with one or more containers",
+		Long:  logsPodDescription,
+		// We dont want users to invoke latest and pod togather
+		Args: func(cmd *cobra.Command, args []string) error {
+			switch {
+			case registry.IsRemote() && logsPodOptions.Latest:
+				return errors.New(cmd.Name() + " does not support 'latest' when run remotely")
+			case len(args) > 1:
+				return errors.New("requires exactly 1 arg")
+			case logsPodOptions.Latest && len(args) > 0:
+				return errors.New("--latest and pods cannot be used together")
+			case !logsPodOptions.Latest && len(args) < 1:
+				return errors.New("specify at least one pod name or ID to log")
+			}
+			return nil
+		},
+		RunE:              logs,
+		ValidArgsFunction: common.AutocompletePods,
+		Example: `podman pod logs podID
+		podman pod logs -c ctrname podName
+		podman pod logs --tail 2 mywebserver
+		podman pod logs --follow=true --since 10m podID
+		podman pod logs mywebserver`,
+	}
+
+	containerLogsCommand = &cobra.Command{
+		Use:               logsPodCommand.Use,
+		Short:             logsPodCommand.Short,
+		Long:              logsPodCommand.Long,
+		Args:              logsPodCommand.Args,
+		RunE:              logsPodCommand.RunE,
+		ValidArgsFunction: logsPodCommand.ValidArgsFunction,
+		Example: `podman pod logs podId
+		podman pod logs -c ctrname podName
+		podman pod logs --tail 2 mywebserver
+		podman pod logs --follow=true --since 10m podID`,
+	}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: logsPodCommand,
+	})
+	logsFlags(logsPodCommand)
+	validate.AddLatestFlag(logsPodCommand, &logsPodOptions.Latest)
+
+	// container logs
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: containerLogsCommand,
+		Parent:  podCmd,
+	})
+	logsFlags(containerLogsCommand)
+	validate.AddLatestFlag(containerLogsCommand, &logsPodOptions.Latest)
+}
+
+func logsFlags(cmd *cobra.Command) {
+	flags := cmd.Flags()
+
+	flags.BoolVar(&logsPodOptions.Details, "details", false, "Show extra details provided to the logs")
+	flags.BoolVarP(&logsPodOptions.Follow, "follow", "f", false, "Follow log output.")
+
+	containerNameFlag := "container"
+	flags.StringVarP(&logsPodOptions.ContainerName, containerNameFlag, "c", "", "Filter logs by container name or id which belongs to pod")
+	_ = cmd.RegisterFlagCompletionFunc(containerNameFlag, common.AutocompleteContainers)
+
+	sinceFlagName := "since"
+	flags.StringVar(&logsPodOptions.SinceRaw, sinceFlagName, "", "Show logs since TIMESTAMP")
+	_ = cmd.RegisterFlagCompletionFunc(sinceFlagName, completion.AutocompleteNone)
+
+	untilFlagName := "until"
+	flags.StringVar(&logsPodOptions.UntilRaw, untilFlagName, "", "Show logs until TIMESTAMP")
+	_ = cmd.RegisterFlagCompletionFunc(untilFlagName, completion.AutocompleteNone)
+
+	tailFlagName := "tail"
+	flags.Int64Var(&logsPodOptions.Tail, tailFlagName, -1, "Output the specified number of LINES at the end of the logs.")
+	_ = cmd.RegisterFlagCompletionFunc(tailFlagName, completion.AutocompleteNone)
+
+	flags.BoolVarP(&logsPodOptions.Timestamps, "timestamps", "t", false, "Output the timestamps in the log")
+	flags.SetInterspersed(false)
+	_ = flags.MarkHidden("details")
+}
+
+func logs(_ *cobra.Command, args []string) error {
+	if logsPodOptions.SinceRaw != "" {
+		// parse time, error out if something is wrong
+		since, err := util.ParseInputTime(logsPodOptions.SinceRaw, true)
+		if err != nil {
+			return errors.Wrapf(err, "error parsing --since %q", logsPodOptions.SinceRaw)
+		}
+		logsPodOptions.Since = since
+	}
+	if logsPodOptions.UntilRaw != "" {
+		// parse time, error out if something is wrong
+		until, err := util.ParseInputTime(logsPodOptions.UntilRaw, false)
+		if err != nil {
+			return errors.Wrapf(err, "error parsing --until %q", logsPodOptions.UntilRaw)
+		}
+		logsPodOptions.Until = until
+	}
+
+	// Remote can only process one container at a time
+	if registry.IsRemote() && logsPodOptions.ContainerName == "" {
+		return errors.Wrapf(define.ErrInvalidArg, "-c or --container cannot be empty")
+	}
+
+	logsPodOptions.StdoutWriter = os.Stdout
+	logsPodOptions.StderrWriter = os.Stderr
+	return registry.ContainerEngine().PodLogs(registry.GetContext(), args[0], logsPodOptions.PodLogsOptions)
+}