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>

9 files changed, 345 insertions, 2 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)
+}
diff --git a/docs/source/markdown/podman-pod-logs.1.md b/docs/source/markdown/podman-pod-logs.1.md
new file mode 100644
index 000000000..8378f2eea
--- /dev/null
+++ b/docs/source/markdown/podman-pod-logs.1.md
@@ -0,0 +1,88 @@
+% podman-pod-logs(1)
+
+## NAME
+podman\-pod\-logs - Displays logs for pod with one or more containers
+
+## SYNOPSIS
+**podman pod logs** [*options*] *pod*
+
+## DESCRIPTION
+The podman pod logs command batch-retrieves whatever logs are present with all the containers of a pod. Pod logs can be filtered by container name or id using flag **-c** or **--container** if needed.
+
+Note: Long running command of `podman pod log` with a `-f` or `--follow` needs to be reinvoked if new container is added to the pod dynamically otherwise logs of newly added containers would not be visible in log stream.
+
+## OPTIONS
+
+#### **--container**, **-c**
+
+By default `podman pod logs` retrives logs for all the containers available within the pod differentiate by field `container`. However there are use-cases where user would want to limit the log stream only to a particular container of a pod for such cases `-c` can be used like `podman pod logs -c ctrNameorID podname`.
+
+#### **--follow**, **-f**
+
+Follow log output.  Default is false.
+
+Note: If you are following a pod which is removed `podman pod rm`, then there is a
+chance the the log file will be removed before `podman pod logs` reads the final content.
+
+#### **--latest**, **-l**
+
+Instead of providing the pod name or id, get logs of the last created pod. (This option is not available with the remote Podman client)
+
+#### **--since**=*TIMESTAMP*
+
+Show logs since TIMESTAMP. The --since option can be Unix timestamps, date formatted timestamps, or Go duration
+strings (e.g. 10m, 1h30m) computed relative to the client machine's time. Supported formats for date formatted
+time stamps include RFC3339Nano, RFC3339, 2006-01-02T15:04:05, 2006-01-02T15:04:05.999999999, 2006-01-02Z07:00,
+and 2006-01-02.
+
+#### **--until**=*TIMESTAMP*
+
+Show logs until TIMESTAMP. The --until option can be Unix timestamps, date formatted timestamps, or Go duration
+strings (e.g. 10m, 1h30m) computed relative to the client machine's time. Supported formats for date formatted
+time stamps include RFC3339Nano, RFC3339, 2006-01-02T15:04:05, 2006-01-02T15:04:05.999999999, 2006-01-02Z07:00,
+and 2006-01-02.
+
+
+#### **--tail**=*LINES*
+
+Output the specified number of LINES at the end of the logs.  LINES must be an integer.  Defaults to -1,
+which prints all lines
+
+#### **--timestamps**, **-t**
+
+Show timestamps in the log outputs.  The default is false
+
+## EXAMPLE
+
+To view a pod's logs:
+```
+podman pod logs -t podIdorName
+```
+
+To view logs of a specific container on the pod
+```
+podman pod logs -c ctrIdOrName podIdOrName
+```
+
+To view all pod logs:
+```
+podman pod logs -t --since 0 myserver-pod-1
+```
+
+To view a pod's logs since a certain time:
+```
+podman pod logs -t --since 2017-08-07T10:10:09.055837383-04:00 myserver-pod-1
+```
+
+To view a pod's logs generated in the last 10 minutes:
+```
+podman pod logs --since 10m myserver-pod-1
+```
+
+To view a pod's logs until 30 minutes ago:
+```
+podman pod logs --until 30m myserver-pod-1
+```
+
+## SEE ALSO
+podman(1), podman-pod-start(1), podman-pod-rm(1), podman-logs(1)
diff --git a/docs/source/markdown/podman-pod.1.md b/docs/source/markdown/podman-pod.1.md
index e5a8207e9..9de2442bd 100644
--- a/docs/source/markdown/podman-pod.1.md
+++ b/docs/source/markdown/podman-pod.1.md
@@ -17,11 +17,12 @@ podman pod is a set of subcommands that manage pods, or groups of containers.
 | exists  | [podman-pod-exists(1)](podman-pod-exists.1.md)    | Check if a pod exists in local storage.                                           |
 | inspect | [podman-pod-inspect(1)](podman-pod-inspect.1.md)  | Displays information describing a pod.                                            |
 | kill    | [podman-pod-kill(1)](podman-pod-kill.1.md)        | Kill the main process of each container in one or more pods.                      |
+| logs    | [podman-pod-logs(1)](podman-pod-logs.1.md)        | Displays logs for pod with one or more containers.                                |
 | pause   | [podman-pod-pause(1)](podman-pod-pause.1.md)      | Pause one or more pods.                                                           |
-| prune   | [podman-pod-prune(1)](podman-pod-prune.1.md)      | Remove all stopped pods and their containers.                                                          |
+| prune   | [podman-pod-prune(1)](podman-pod-prune.1.md)      | Remove all stopped pods and their containers.                                     |
 | ps      | [podman-pod-ps(1)](podman-pod-ps.1.md)            | Prints out information about pods.                                                |
 | restart | [podman-pod-restart(1)](podman-pod-restart.1.md)  | Restart one or more pods.                                                         |
-| rm      | [podman-pod-rm(1)](podman-pod-rm.1.md)            | Remove one or more stopped pods and containers.                                                          |
+| rm      | [podman-pod-rm(1)](podman-pod-rm.1.md)            | Remove one or more stopped pods and containers.                                   |
 | start   | [podman-pod-start(1)](podman-pod-start.1.md)      | Start one or more pods.                                                           |
 | stats   | [podman-pod-stats(1)](podman-pod-stats.1.md)      | Display a live stream of resource usage stats for containers in one or more pods. |
 | stop    | [podman-pod-stop(1)](podman-pod-stop.1.md)        | Stop one or more pods.                                                            |
diff --git a/docs/source/pod.rst b/docs/source/pod.rst
index 2df377762..d9ad07d83 100644
--- a/docs/source/pod.rst
+++ b/docs/source/pod.rst
@@ -9,6 +9,8 @@ Pod
 
 :doc:`kill <markdown/podman-pod-kill.1>` Send the specified signal or SIGKILL to containers in pod
 
+:doc:`logs <markdown/podman-pod-logs.1>` Displays logs for pod with one or more containers
+
 :doc:`pause <markdown/podman-pause.1>` Pause one or more pods
 
 :doc:`prune <markdown/podman-pod-prune.1>` Remove all stopped pods and their containers
diff --git a/pkg/domain/entities/engine_container.go b/pkg/domain/entities/engine_container.go
index bd011d309..93fa7a20f 100644
--- a/pkg/domain/entities/engine_container.go
+++ b/pkg/domain/entities/engine_container.go
@@ -72,6 +72,7 @@ type ContainerEngine interface {
 	PodExists(ctx context.Context, nameOrID string) (*BoolReport, error)
 	PodInspect(ctx context.Context, options PodInspectOptions) (*PodInspectReport, error)
 	PodKill(ctx context.Context, namesOrIds []string, options PodKillOptions) ([]*PodKillReport, error)
+	PodLogs(ctx context.Context, pod string, options PodLogsOptions) error
 	PodPause(ctx context.Context, namesOrIds []string, options PodPauseOptions) ([]*PodPauseReport, error)
 	PodPrune(ctx context.Context, options PodPruneOptions) ([]*PodPruneReport, error)
 	PodPs(ctx context.Context, options PodPSOptions) ([]*ListPodsReport, error)
diff --git a/pkg/domain/entities/pods.go b/pkg/domain/entities/pods.go
index 10bd7e5ce..d9dd0c532 100644
--- a/pkg/domain/entities/pods.go
+++ b/pkg/domain/entities/pods.go
@@ -133,6 +133,14 @@ type PodCreateOptions struct {
 	Userns             specgen.Namespace
 }
 
+// PodLogsOptions describes the options to extract pod logs.
+type PodLogsOptions struct {
+	// Other fields are exactly same as ContainerLogOpts
+	ContainerLogsOptions
+	// If specified will only fetch the logs of specified container
+	ContainerName string
+}
+
 type ContainerCreateOptions struct {
 	Annotation        []string
 	Attach            []string
@@ -426,3 +434,22 @@ func ValidatePodStatsOptions(args []string, options *PodStatsOptions) error {
 		return errors.New("--all, --latest and arguments cannot be used together")
 	}
 }
+
+// Converts PodLogOptions to ContainerLogOptions
+func PodLogsOptionsToContainerLogsOptions(options PodLogsOptions) ContainerLogsOptions {
+	// PodLogsOptions are similar but contains few extra fields like ctrName
+	// So cast other values as is so we can re-use the code
+	containerLogsOpts := ContainerLogsOptions{
+		Details:      options.Details,
+		Latest:       options.Latest,
+		Follow:       options.Follow,
+		Names:        options.Names,
+		Since:        options.Since,
+		Until:        options.Until,
+		Tail:         options.Tail,
+		Timestamps:   options.Timestamps,
+		StdoutWriter: options.StdoutWriter,
+		StderrWriter: options.StderrWriter,
+	}
+	return containerLogsOpts
+}
diff --git a/pkg/domain/infra/abi/pods.go b/pkg/domain/infra/abi/pods.go
index 98233f60d..6b432c214 100644
--- a/pkg/domain/infra/abi/pods.go
+++ b/pkg/domain/infra/abi/pods.go
@@ -83,6 +83,46 @@ func (ic *ContainerEngine) PodKill(ctx context.Context, namesOrIds []string, opt
 	return reports, nil
 }
 
+func (ic *ContainerEngine) PodLogs(ctx context.Context, nameOrID string, options entities.PodLogsOptions) error {
+	// Implementation accepts slice
+	podName := []string{nameOrID}
+	pod, err := getPodsByContext(false, options.Latest, podName, ic.Libpod)
+	if err != nil {
+		return err
+	}
+	// Get pod containers
+	podCtrs, err := pod[0].AllContainers()
+	if err != nil {
+		return err
+	}
+
+	ctrNames := []string{}
+	// Check if `kubectl pod logs -c ctrname <podname>` alike command is used
+	if options.ContainerName != "" {
+		ctrFound := false
+		for _, ctr := range podCtrs {
+			if ctr.ID() == options.ContainerName || ctr.Name() == options.ContainerName {
+				ctrNames = append(ctrNames, options.ContainerName)
+				ctrFound = true
+			}
+		}
+		if !ctrFound {
+			return errors.Wrapf(define.ErrNoSuchCtr, "container %s is not in pod %s", options.ContainerName, nameOrID)
+		}
+	} else {
+		// No container name specified select all containers
+		for _, ctr := range podCtrs {
+			ctrNames = append(ctrNames, ctr.Name())
+		}
+	}
+
+	// PodLogsOptions are similar but contains few extra fields like ctrName
+	// So cast other values as is so we can re-use the code
+	containerLogsOpts := entities.PodLogsOptionsToContainerLogsOptions(options)
+
+	return ic.ContainerLogs(ctx, ctrNames, containerLogsOpts)
+}
+
 func (ic *ContainerEngine) PodPause(ctx context.Context, namesOrIds []string, options entities.PodPauseOptions) ([]*entities.PodPauseReport, error) {
 	reports := []*entities.PodPauseReport{}
 	pods, err := getPodsByContext(options.All, options.Latest, namesOrIds, ic.Libpod)
diff --git a/pkg/domain/infra/tunnel/pods.go b/pkg/domain/infra/tunnel/pods.go
index 480adb88a..8139216b3 100644
--- a/pkg/domain/infra/tunnel/pods.go
+++ b/pkg/domain/infra/tunnel/pods.go
@@ -42,6 +42,16 @@ func (ic *ContainerEngine) PodKill(ctx context.Context, namesOrIds []string, opt
 	return reports, nil
 }
 
+func (ic *ContainerEngine) PodLogs(_ context.Context, nameOrIDs string, options entities.PodLogsOptions) error {
+	// PodLogsOptions are similar but contains few extra fields like ctrName
+	// So cast other values as is so we can re-use the code
+	containerLogsOpts := entities.PodLogsOptionsToContainerLogsOptions(options)
+
+	// interface only accepts slice, keep everything consistent
+	name := []string{options.ContainerName}
+	return ic.ContainerLogs(nil, name, containerLogsOpts)
+}
+
 func (ic *ContainerEngine) PodPause(ctx context.Context, namesOrIds []string, options entities.PodPauseOptions) ([]*entities.PodPauseReport, error) {
 	foundPods, err := getPodsByContext(ic.ClientCtx, options.All, namesOrIds)
 	if err != nil {
diff --git a/test/e2e/play_kube_test.go b/test/e2e/play_kube_test.go
index ab496f0eb..5d875effd 100644
--- a/test/e2e/play_kube_test.go
+++ b/test/e2e/play_kube_test.go
@@ -1289,6 +1289,40 @@ var _ = Describe("Podman play kube", func() {
 		Expect(logs.OutputToString()).To(ContainSubstring("hello world"))
 	})
 
+	It("podman pod logs test", func() {
+		SkipIfRemote("podman-remote pod logs -c is mandatory for remote machine")
+		p := getPod(withCtr(getCtr(withCmd([]string{"echo", "hello"}), withArg([]string{"world"}))))
+
+		err := generateKubeYaml("pod", p, kubeYaml)
+		Expect(err).To(BeNil())
+
+		kube := podmanTest.Podman([]string{"play", "kube", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube).Should(Exit(0))
+
+		logs := podmanTest.Podman([]string{"pod", "logs", p.Name})
+		logs.WaitWithDefaultTimeout()
+		Expect(logs).Should(Exit(0))
+		Expect(logs.OutputToString()).To(ContainSubstring("hello world"))
+	})
+
+	It("podman-remote pod logs test", func() {
+		// -c or --container is required in podman-remote due to api limitation.
+		p := getPod(withCtr(getCtr(withCmd([]string{"echo", "hello"}), withArg([]string{"world"}))))
+
+		err := generateKubeYaml("pod", p, kubeYaml)
+		Expect(err).To(BeNil())
+
+		kube := podmanTest.Podman([]string{"play", "kube", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube).Should(Exit(0))
+
+		logs := podmanTest.Podman([]string{"pod", "logs", "-c", getCtrNameInPod(p), p.Name})
+		logs.WaitWithDefaultTimeout()
+		Expect(logs).Should(Exit(0))
+		Expect(logs.OutputToString()).To(ContainSubstring("hello world"))
+	})
+
 	It("podman play kube test restartPolicy", func() {
 		// podName,  set,  expect
 		testSli := [][]string{