Add watch mode to podman ps

allows users to "watch" the output of podman ps on a set interval in
seconds. in watch mode, the screen is cleared between intervals as well.

podman -ps -w1 watches on 1 second intervals

Signed-off-by: baude <bbaude@redhat.com>

4 files changed, 166 insertions, 128 deletions

diff --git a/cmd/podman/cliconfig/config.go b/cmd/podman/cliconfig/config.go
index 884bd7fdb..f7ac0de6c 100644
--- a/cmd/podman/cliconfig/config.go
+++ b/cmd/podman/cliconfig/config.go
@@ -357,6 +357,7 @@ type PsValues struct {
 	Size      bool
 	Sort      string
 	Sync      bool
+	Watch     uint
 }
 
 type PullValues struct {
diff --git a/cmd/podman/ps.go b/cmd/podman/ps.go
index 27774f95d..fe9efeba4 100644
--- a/cmd/podman/ps.go
+++ b/cmd/podman/ps.go
@@ -12,6 +12,7 @@ import (
 	"text/tabwriter"
 	"time"
 
+	tm "github.com/buger/goterm"
 	"github.com/containers/buildah/pkg/formats"
 	"github.com/containers/libpod/cmd/podman/cliconfig"
 	"github.com/containers/libpod/cmd/podman/libpodruntime"
@@ -21,7 +22,7 @@ import (
 	"github.com/containers/libpod/pkg/util"
 	"github.com/cri-o/ocicni/pkg/ocicni"
 	"github.com/docker/go-units"
-	opentracing "github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
@@ -191,6 +192,7 @@ func psInit(command *cliconfig.PsValues) {
 	flags.BoolVarP(&command.Size, "size", "s", false, "Display the total file sizes")
 	flags.StringVar(&command.Sort, "sort", "created", "Sort output by command, created, id, image, names, runningfor, size, or status")
 	flags.BoolVar(&command.Sync, "sync", false, "Sync container state with OCI runtime")
+	flags.UintVarP(&command.Watch, "watch", "w", 0, "Watch the ps output on an interval in seconds")
 
 	markFlagHiddenForRemoteClient("latest", flags)
 }
@@ -209,10 +211,15 @@ func psCmd(c *cliconfig.PsValues) error {
 		defer span.Finish()
 	}
 
-	var (
-		filterFuncs      []libpod.ContainerFilter
-		outputContainers []*libpod.Container
-	)
+	var watch bool
+
+	if c.Watch > 0 {
+		watch = true
+	}
+
+	if c.Watch > 0 && c.Latest {
+		return errors.New("the watch and latest flags cannot be used together")
+	}
 
 	if err := checkFlagsPassed(c); err != nil {
 		return errors.Wrapf(err, "error with flags passed")
@@ -225,135 +232,24 @@ func psCmd(c *cliconfig.PsValues) error {
 
 	defer runtime.Shutdown(false)
 
-	opts := shared.PsOptions{
-		All:       c.All,
-		Format:    c.Format,
-		Last:      c.Last,
-		Latest:    c.Latest,
-		NoTrunc:   c.NoTrunct,
-		Pod:       c.Pod,
-		Quiet:     c.Quiet,
-		Size:      c.Size,
-		Namespace: c.Namespace,
-		Sort:      c.Sort,
-		Sync:      c.Sync,
-	}
-
-	filters := c.Filter
-	if len(filters) > 0 {
-		for _, f := range filters {
-			filterSplit := strings.SplitN(f, "=", 2)
-			if len(filterSplit) < 2 {
-				return errors.Errorf("filter input must be in the form of filter=value: %s is invalid", f)
-			}
-			generatedFunc, err := generateContainerFilterFuncs(filterSplit[0], filterSplit[1], runtime)
-			if err != nil {
-				return errors.Wrapf(err, "invalid filter")
-			}
-			filterFuncs = append(filterFuncs, generatedFunc)
-		}
-	}
-
-	if !opts.Latest {
-		// Get all containers
-		containers, err := runtime.GetContainers(filterFuncs...)
-		if err != nil {
-			return err
-		}
-
-		// We only want the last few containers
-		if opts.Last > 0 && opts.Last <= len(containers) {
-			return errors.Errorf("--last not yet supported")
-		} else {
-			outputContainers = containers
-		}
-	} else {
-		// Get just the latest container
-		// Ignore filters
-		latestCtr, err := runtime.GetLatestContainer()
-		if err != nil {
-			return err
-		}
-
-		outputContainers = []*libpod.Container{latestCtr}
-	}
-
-	maxWorkers := shared.Parallelize("ps")
-	if c.GlobalIsSet("max-workers") {
-		maxWorkers = c.GlobalFlags.MaxWorks
-	}
-	logrus.Debugf("Setting maximum workers to %d", maxWorkers)
-
-	pss := shared.PBatch(outputContainers, maxWorkers, opts)
-	if opts.Sort != "" {
-		pss, err = sortPsOutput(opts.Sort, pss)
-		if err != nil {
+	if !watch {
+		if err := psDisplay(c, runtime); err != nil {
 			return err
 		}
-	}
-
-	// If quiet, print only cids and return
-	if opts.Quiet {
-		return printQuiet(pss)
-	}
-
-	// If the user wants their own GO template format
-	if opts.Format != "" {
-		if opts.Format == "json" {
-			return dumpJSON(pss)
-		}
-		return printFormat(opts.Format, pss)
-	}
-
-	// Define a tab writer with stdout as the output
-	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
-	defer w.Flush()
-
-	// Output standard PS headers
-	if !opts.Namespace {
-		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\t%s", hid, himage, hcommand, hcreated, hstatus, hports, hnames)
-		// User wants pod info
-		if opts.Pod {
-			fmt.Fprintf(w, "\t%s", hpod)
-		}
-		//User wants size info
-		if opts.Size {
-			fmt.Fprintf(w, "\t%s", hsize)
-		}
 	} else {
-		// Output Namespace headers
-		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s", hid, hnames, nspid, nscgroup, nsipc, nsmnt, nsnet, nspidns, nsuserns, nsuts)
-	}
-
-	// Now iterate each container and output its information
-	for _, container := range pss {
-
-		// Standard PS output
-		if !opts.Namespace {
-			fmt.Fprintf(w, "\n%s\t%s\t%s\t%s\t%s\t%s\t%s", container.ID, container.Image, container.Command, container.Created, container.Status, container.Ports, container.Names)
-			// User wants pod info
-			if opts.Pod {
-				fmt.Fprintf(w, "\t%s", container.Pod)
+		for {
+			tm.Clear()
+			tm.MoveCursor(1, 1)
+			tm.Flush()
+			if err := psDisplay(c, runtime); err != nil {
+				return err
 			}
-			//User wants size info
-			if opts.Size {
-				var size string
-				if container.Size == nil {
-					size = units.HumanSizeWithPrecision(0, 0)
-				} else {
-					size = units.HumanSizeWithPrecision(float64(container.Size.RwSize), 3) + " (virtual " + units.HumanSizeWithPrecision(float64(container.Size.RootFsSize), 3) + ")"
-					fmt.Fprintf(w, "\t%s", size)
-				}
-			}
-
-		} else {
-			// Print namespace information
-			ns := shared.GetNamespaces(container.Pid)
-			fmt.Fprintf(w, "\n%s\t%s\t%d\t%s\t%s\t%s\t%s\t%s\t%s\t%s", container.ID, container.Names, container.Pid, ns.Cgroup, ns.IPC, ns.MNT, ns.NET, ns.PIDNS, ns.User, ns.UTS)
+			time.Sleep(time.Duration(c.Watch) * time.Second)
+			tm.Clear()
+			tm.MoveCursor(1, 1)
+			tm.Flush()
 		}
-
 	}
-	fmt.Fprint(w, "\n")
 	return nil
 }
 
@@ -654,3 +550,139 @@ func dumpJSON(containers []shared.PsContainerOutput) error {
 	os.Stdout.Write(b)
 	return nil
 }
+
+func psDisplay(c *cliconfig.PsValues, runtime *libpod.Runtime) error {
+	var (
+		filterFuncs      []libpod.ContainerFilter
+		outputContainers []*libpod.Container
+		err              error
+	)
+	opts := shared.PsOptions{
+		All:       c.All,
+		Format:    c.Format,
+		Last:      c.Last,
+		Latest:    c.Latest,
+		NoTrunc:   c.NoTrunct,
+		Pod:       c.Pod,
+		Quiet:     c.Quiet,
+		Size:      c.Size,
+		Namespace: c.Namespace,
+		Sort:      c.Sort,
+		Sync:      c.Sync,
+	}
+
+	maxWorkers := shared.Parallelize("ps")
+	if c.GlobalIsSet("max-workers") {
+		maxWorkers = c.GlobalFlags.MaxWorks
+	}
+	logrus.Debugf("Setting maximum workers to %d", maxWorkers)
+
+	filters := c.Filter
+	if len(filters) > 0 {
+		for _, f := range filters {
+			filterSplit := strings.SplitN(f, "=", 2)
+			if len(filterSplit) < 2 {
+				return errors.Errorf("filter input must be in the form of filter=value: %s is invalid", f)
+			}
+			generatedFunc, err := generateContainerFilterFuncs(filterSplit[0], filterSplit[1], runtime)
+			if err != nil {
+				return errors.Wrapf(err, "invalid filter")
+			}
+			filterFuncs = append(filterFuncs, generatedFunc)
+		}
+	}
+	if !opts.Latest {
+		// Get all containers
+		containers, err := runtime.GetContainers(filterFuncs...)
+		if err != nil {
+			return err
+		}
+
+		// We only want the last few containers
+		if opts.Last > 0 && opts.Last <= len(containers) {
+			return errors.Errorf("--last not yet supported")
+		} else {
+			outputContainers = containers
+		}
+	} else {
+		// Get just the latest container
+		// Ignore filters
+		latestCtr, err := runtime.GetLatestContainer()
+		if err != nil {
+			return err
+		}
+
+		outputContainers = []*libpod.Container{latestCtr}
+	}
+
+	pss := shared.PBatch(outputContainers, maxWorkers, opts)
+	if opts.Sort != "" {
+		pss, err = sortPsOutput(opts.Sort, pss)
+		if err != nil {
+			return err
+		}
+	}
+
+	// If quiet, print only cids and return
+	if opts.Quiet {
+		return printQuiet(pss)
+	}
+
+	// If the user wants their own GO template format
+	if opts.Format != "" {
+		if opts.Format == "json" {
+			return dumpJSON(pss)
+		}
+		return printFormat(opts.Format, pss)
+	}
+
+	// Define a tab writer with stdout as the output
+	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
+
+	// Output standard PS headers
+	if !opts.Namespace {
+		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\t%s", hid, himage, hcommand, hcreated, hstatus, hports, hnames)
+		// User wants pod info
+		if opts.Pod {
+			fmt.Fprintf(w, "\t%s", hpod)
+		}
+		//User wants size info
+		if opts.Size {
+			fmt.Fprintf(w, "\t%s", hsize)
+		}
+	} else {
+		// Output Namespace headers
+		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s", hid, hnames, nspid, nscgroup, nsipc, nsmnt, nsnet, nspidns, nsuserns, nsuts)
+	}
+
+	// Now iterate each container and output its information
+	for _, container := range pss {
+
+		// Standard PS output
+		if !opts.Namespace {
+			fmt.Fprintf(w, "\n%s\t%s\t%s\t%s\t%s\t%s\t%s", container.ID, container.Image, container.Command, container.Created, container.Status, container.Ports, container.Names)
+			// User wants pod info
+			if opts.Pod {
+				fmt.Fprintf(w, "\t%s", container.Pod)
+			}
+			//User wants size info
+			if opts.Size {
+				var size string
+				if container.Size == nil {
+					size = units.HumanSizeWithPrecision(0, 0)
+				} else {
+					size = units.HumanSizeWithPrecision(float64(container.Size.RwSize), 3) + " (virtual " + units.HumanSizeWithPrecision(float64(container.Size.RootFsSize), 3) + ")"
+					fmt.Fprintf(w, "\t%s", size)
+				}
+			}
+
+		} else {
+			// Print namespace information
+			ns := shared.GetNamespaces(container.Pid)
+			fmt.Fprintf(w, "\n%s\t%s\t%d\t%s\t%s\t%s\t%s\t%s\t%s\t%s", container.ID, container.Names, container.Pid, ns.Cgroup, ns.IPC, ns.MNT, ns.NET, ns.PIDNS, ns.User, ns.UTS)
+		}
+
+	}
+	fmt.Fprint(w, "\n")
+	return w.Flush()
+}
diff --git a/completions/bash/podman b/completions/bash/podman
index 798d49ceb..a3f381962 100644
--- a/completions/bash/podman
+++ b/completions/bash/podman
@@ -2205,6 +2205,7 @@ _podman_ps() {
      --format
      --last -n
      --sort
+     --watch -w
      "
      local boolean_options="
 	  --all -a
diff --git a/docs/podman-ps.1.md b/docs/podman-ps.1.md
index 685a52bda..a4a521b39 100644
--- a/docs/podman-ps.1.md
+++ b/docs/podman-ps.1.md
@@ -113,6 +113,10 @@ In some cases, a container's state in the runtime can become out of sync with Po
 This will update Podman's state based on what the OCI runtime reports.
 Forcibly syncing is much slower, but can resolve inconsistent state issues.
 
+**--watch, -w**
+
+Refresh the output with current containers on an interval in seconds.
+
 ## EXAMPLES
 
 ```