Merge pull request #8187 from jwhonce/wip/table

Restore --format table header support

12 files changed, 221 insertions, 112 deletions

diff --git a/cmd/podman/containers/ps.go b/cmd/podman/containers/ps.go
index 90f4db19c..7da430bc6 100644
--- a/cmd/podman/containers/ps.go
+++ b/cmd/podman/containers/ps.go
@@ -12,6 +12,7 @@ import (
 
 	tm "github.com/buger/goterm"
 	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/cmd/podman/utils"
 	"github.com/containers/podman/v2/cmd/podman/validate"
@@ -40,9 +41,8 @@ var (
 	listOpts = entities.ContainerListOptions{
 		Filters: make(map[string][]string),
 	}
-	filters        []string
-	noTrunc        bool
-	defaultHeaders = "CONTAINER ID\tIMAGE\tCOMMAND\tCREATED\tSTATUS\tPORTS\tNAMES"
+	filters []string
+	noTrunc bool
 )
 
 func init() {
@@ -91,10 +91,6 @@ func checkFlags(c *cobra.Command) error {
 		if listOpts.Size || listOpts.Namespace {
 			return errors.Errorf("quiet conflicts with size and namespace")
 		}
-		if c.Flag("format").Changed && !report.IsJSON(listOpts.Format) {
-			// Quiet is overridden by Go template output.
-			listOpts.Quiet = false
-		}
 	}
 	// Size and namespace conflict with each other
 	if listOpts.Size && listOpts.Namespace {
@@ -155,7 +151,7 @@ func getResponses() ([]entities.ListContainer, error) {
 	return responses, nil
 }
 
-func ps(cmd *cobra.Command, args []string) error {
+func ps(cmd *cobra.Command, _ []string) error {
 	if err := checkFlags(cmd); err != nil {
 		return err
 	}
@@ -180,24 +176,22 @@ func ps(cmd *cobra.Command, args []string) error {
 	switch {
 	case report.IsJSON(listOpts.Format):
 		return jsonOut(listContainers)
-	case listOpts.Quiet:
+	case listOpts.Quiet && !cmd.Flags().Changed("format"):
 		return quietOut(listContainers)
 	}
-	// Output table Watch > 0 will refresh screen
 
 	responses := make([]psReporter, 0, len(listContainers))
 	for _, r := range listContainers {
 		responses = append(responses, psReporter{r})
 	}
 
-	var headers, format string
+	hdrs, format := createPsOut()
 	if cmd.Flags().Changed("format") {
-		headers = ""
 		format = report.NormalizeFormat(listOpts.Format)
-	} else {
-		headers, format = createPsOut()
+		format = parse.EnforceRange(format)
 	}
-	format = headers + "{{range . }}" + format + "{{end}}"
+	ns := strings.NewReplacer(".Namespaces.", ".")
+	format = ns.Replace(format)
 
 	tmpl, err := template.New("listContainers").Parse(format)
 	if err != nil {
@@ -206,13 +200,19 @@ func ps(cmd *cobra.Command, args []string) error {
 	w := tabwriter.NewWriter(os.Stdout, 8, 2, 2, ' ', 0)
 	defer w.Flush()
 
-	if listOpts.Watch > 0 {
-		for {
-			var responses []psReporter
-			tm.Clear()
-			tm.MoveCursor(1, 1)
-			tm.Flush()
+	headers := func() error { return nil }
+	if !(listOpts.Quiet || cmd.Flags().Changed("format")) {
+		headers = func() error {
+			return tmpl.Execute(w, hdrs)
+		}
+	}
 
+	switch {
+	// Output table Watch > 0 will refresh screen
+	case listOpts.Watch > 0:
+		// responses will grow to the largest number of processes reported on, but will not thrash the gc
+		var responses []psReporter
+		for ; ; responses = responses[:0] {
 			if ctnrs, err := getResponses(); err != nil {
 				return err
 			} else {
@@ -221,18 +221,27 @@ func ps(cmd *cobra.Command, args []string) error {
 				}
 			}
 
+			tm.Clear()
+			tm.MoveCursor(1, 1)
+			tm.Flush()
+
+			if err := headers(); err != nil {
+				return err
+			}
 			if err := tmpl.Execute(w, responses); err != nil {
 				return err
 			}
 			if err := w.Flush(); err != nil {
+				// we usually do not care about Flush() failures but here do not loop if Flush() has failed
 				return err
 			}
+
 			time.Sleep(time.Duration(listOpts.Watch) * time.Second)
-			tm.Clear()
-			tm.MoveCursor(1, 1)
-			tm.Flush()
 		}
-	} else if listOpts.Watch < 1 {
+	default:
+		if err := headers(); err != nil {
+			return err
+		}
 		if err := tmpl.Execute(w, responses); err != nil {
 			return err
 		}
@@ -241,30 +250,36 @@ func ps(cmd *cobra.Command, args []string) error {
 }
 
 // cannot use report.Headers() as it doesn't support structures as fields
-func createPsOut() (string, string) {
+func createPsOut() ([]map[string]string, string) {
+	hdrs := report.Headers(psReporter{}, map[string]string{
+		"Cgroup":       "cgroupns",
+		"CreatedHuman": "created",
+		"ID":           "container id",
+		"IPC":          "ipc",
+		"MNT":          "mnt",
+		"NET":          "net",
+		"PIDNS":        "pidns",
+		"Pod":          "pod id",
+		"PodName":      "podname", // undo camelcase space break
+		"UTS":          "uts",
+		"User":         "userns",
+	})
+
 	var row string
 	if listOpts.Namespace {
-		headers := "CONTAINER ID\tNAMES\tPID\tCGROUPNS\tIPC\tMNT\tNET\tPIDNS\tUSERNS\tUTS\n"
-		row := "{{.ID}}\t{{.Names}}\t{{.Pid}}\t{{.Namespaces.Cgroup}}\t{{.Namespaces.IPC}}\t{{.Namespaces.MNT}}\t{{.Namespaces.NET}}\t{{.Namespaces.PIDNS}}\t{{.Namespaces.User}}\t{{.Namespaces.UTS}}\n"
-		return headers, row
-	}
-	headers := defaultHeaders
-	row += "{{.ID}}"
-	row += "\t{{.Image}}\t{{.Command}}\t{{.CreatedHuman}}\t{{.Status}}\t{{.Ports}}\t{{.Names}}"
+		row = "{{.ID}}\t{{.Names}}\t{{.Pid}}\t{{.Namespaces.Cgroup}}\t{{.Namespaces.IPC}}\t{{.Namespaces.MNT}}\t{{.Namespaces.NET}}\t{{.Namespaces.PIDNS}}\t{{.Namespaces.User}}\t{{.Namespaces.UTS}}"
+	} else {
+		row = "{{.ID}}\t{{.Image}}\t{{.Command}}\t{{.CreatedHuman}}\t{{.Status}}\t{{.Ports}}\t{{.Names}}"
 
-	if listOpts.Pod {
-		headers += "\tPOD ID\tPODNAME"
-		row += "\t{{.Pod}}\t{{.PodName}}"
-	}
+		if listOpts.Pod {
+			row += "\t{{.Pod}}\t{{.PodName}}"
+		}
 
-	if listOpts.Size {
-		headers += "\tSIZE"
-		row += "\t{{.Size}}"
+		if listOpts.Size {
+			row += "\t{{.Size}}"
+		}
 	}
-
-	headers = report.NormalizeFormat(headers)
-	row = report.NormalizeFormat(row)
-	return headers, row
+	return hdrs, "{{range .}}" + row + "\n{{end}}"
 }
 
 type psReporter struct {
@@ -367,6 +382,41 @@ func (l psReporter) CreatedHuman() string {
 	return units.HumanDuration(time.Since(time.Unix(l.Created, 0))) + " ago"
 }
 
+// Cgroup exposes .Namespaces.Cgroup
+func (l psReporter) Cgroup() string {
+	return l.Namespaces.Cgroup
+}
+
+// IPC exposes .Namespaces.IPC
+func (l psReporter) IPC() string {
+	return l.Namespaces.IPC
+}
+
+// MNT exposes .Namespaces.MNT
+func (l psReporter) MNT() string {
+	return l.Namespaces.MNT
+}
+
+// NET exposes .Namespaces.NET
+func (l psReporter) NET() string {
+	return l.Namespaces.NET
+}
+
+// PIDNS exposes .Namespaces.PIDNS
+func (l psReporter) PIDNS() string {
+	return l.Namespaces.PIDNS
+}
+
+// User exposes .Namespaces.User
+func (l psReporter) User() string {
+	return l.Namespaces.User
+}
+
+// UTS exposes .Namespaces.UTS
+func (l psReporter) UTS() string {
+	return l.Namespaces.UTS
+}
+
 // portsToString converts the ports used to a string of the from "port1, port2"
 // and also groups a continuous list of ports into a readable format.
 func portsToString(ports []ocicni.PortMapping) string {
diff --git a/cmd/podman/containers/stats.go b/cmd/podman/containers/stats.go
index 85e7a1e82..bfab469ca 100644
--- a/cmd/podman/containers/stats.go
+++ b/cmd/podman/containers/stats.go
@@ -8,6 +8,7 @@ import (
 
 	tm "github.com/buger/goterm"
 	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/cmd/podman/validate"
 	"github.com/containers/podman/v2/libpod/define"
@@ -58,8 +59,7 @@ type statsOptionsCLI struct {
 }
 
 var (
-	statsOptions    statsOptionsCLI
-	defaultStatsRow = "{{.ID}}\t{{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.MemPerc}}\t{{.NetIO}}\t{{.BlockIO}}\t{{.PIDS}}\n"
+	statsOptions statsOptionsCLI
 )
 
 func statFlags(flags *pflag.FlagSet) {
@@ -159,19 +159,19 @@ func outputStats(reports []define.ContainerStats) error {
 	if report.IsJSON(statsOptions.Format) {
 		return outputJSON(stats)
 	}
-	format := defaultStatsRow
-
+	format := "{{.ID}}\t{{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.MemPerc}}\t{{.NetIO}}\t{{.BlockIO}}\t{{.PIDS}}\n"
 	if len(statsOptions.Format) > 0 {
 		format = report.NormalizeFormat(statsOptions.Format)
-	} else if len(statsOptions.Format) < 1 {
-		format = defaultStatsRow
 	}
-	format = "{{range . }}" + format + "{{end}}"
+	format = parse.EnforceRange(format)
+
 	tmpl, err := template.New("stats").Parse(format)
 	if err != nil {
 		return err
 	}
 	w := tabwriter.NewWriter(os.Stdout, 8, 2, 2, ' ', 0)
+	defer w.Flush()
+
 	if len(statsOptions.Format) < 1 {
 		if err := tmpl.Execute(w, headers); err != nil {
 			return err
@@ -180,9 +180,6 @@ func outputStats(reports []define.ContainerStats) error {
 	if err := tmpl.Execute(w, stats); err != nil {
 		return err
 	}
-	if err := w.Flush(); err != nil {
-		return err
-	}
 	return nil
 }
 
diff --git a/cmd/podman/images/history.go b/cmd/podman/images/history.go
index 3075218d1..e9751b365 100644
--- a/cmd/podman/images/history.go
+++ b/cmd/podman/images/history.go
@@ -11,6 +11,7 @@ import (
 	"unicode"
 
 	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/pkg/domain/entities"
 	"github.com/docker/go-units"
@@ -119,7 +120,7 @@ func history(cmd *cobra.Command, args []string) error {
 	case opts.quiet:
 		row = "{{.ID}}\n"
 	}
-	format := "{{range . }}" + row + "{{end}}"
+	format := parse.EnforceRange(row)
 
 	tmpl, err := template.New("report").Parse(format)
 	if err != nil {
diff --git a/cmd/podman/images/list.go b/cmd/podman/images/list.go
index 489b15086..e24631b24 100644
--- a/cmd/podman/images/list.go
+++ b/cmd/podman/images/list.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/containers/common/pkg/report"
 	"github.com/containers/image/v5/docker/reference"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/pkg/domain/entities"
 	"github.com/docker/go-units"
@@ -105,10 +106,10 @@ func images(cmd *cobra.Command, args []string) error {
 		return err
 	}
 	switch {
-	case listFlag.quiet:
-		return writeID(imgs)
 	case report.IsJSON(listFlag.format):
 		return writeJSON(imgs)
+	case listFlag.quiet:
+		return writeID(imgs)
 	default:
 		if cmd.Flag("format").Changed {
 			listFlag.noHeading = true // V1 compatibility
@@ -171,9 +172,13 @@ func writeTemplate(imgs []imageReporter) error {
 	} else {
 		row = report.NormalizeFormat(listFlag.format)
 	}
+	format := parse.EnforceRange(row)
+
+	tmpl, err := template.New("list").Parse(format)
+	if err != nil {
+		return err
+	}
 
-	format := "{{range . }}" + row + "{{end}}"
-	tmpl := template.Must(template.New("list").Parse(format))
 	w := tabwriter.NewWriter(os.Stdout, 8, 2, 2, ' ', 0)
 	defer w.Flush()
 
diff --git a/cmd/podman/images/search.go b/cmd/podman/images/search.go
index b1a1442a6..66256aaa0 100644
--- a/cmd/podman/images/search.go
+++ b/cmd/podman/images/search.go
@@ -8,6 +8,7 @@ import (
 	"github.com/containers/common/pkg/auth"
 	"github.com/containers/common/pkg/report"
 	"github.com/containers/image/v5/types"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/pkg/domain/entities"
 	"github.com/pkg/errors"
@@ -130,26 +131,30 @@ func imageSearch(cmd *cobra.Command, args []string) error {
 	}
 
 	hdrs := report.Headers(entities.ImageSearchReport{}, nil)
-	row := "{{.Index}}\t{{.Name}}\t{{.Description}}\t{{.Stars}}\t{{.Official}}\t{{.Automated}}\n"
-	if searchOptions.ListTags {
+	renderHeaders := true
+	var row string
+	switch {
+	case searchOptions.ListTags:
 		if len(searchOptions.Filters) != 0 {
 			return errors.Errorf("filters are not applicable to list tags result")
 		}
 		row = "{{.Name}}\t{{.Tag}}\n"
-	}
-	if cmd.Flags().Changed("format") {
+	case cmd.Flags().Changed("format"):
+		renderHeaders = parse.HasTable(searchOptions.Format)
 		row = report.NormalizeFormat(searchOptions.Format)
+	default:
+		row = "{{.Index}}\t{{.Name}}\t{{.Description}}\t{{.Stars}}\t{{.Official}}\t{{.Automated}}\n"
 	}
-	row = "{{range .}}" + row + "{{end}}"
+	format := parse.EnforceRange(row)
 
-	tmpl, err := template.New("search").Parse(row)
+	tmpl, err := template.New("search").Parse(format)
 	if err != nil {
 		return err
 	}
 	w := tabwriter.NewWriter(os.Stdout, 8, 2, 2, ' ', 0)
 	defer w.Flush()
 
-	if !cmd.Flags().Changed("format") {
+	if renderHeaders {
 		if err := tmpl.Execute(w, hdrs); err != nil {
 			return errors.Wrapf(err, "failed to write search column headers")
 		}
diff --git a/cmd/podman/networks/list.go b/cmd/podman/networks/list.go
index 532af631e..f68e4ed75 100644
--- a/cmd/podman/networks/list.go
+++ b/cmd/podman/networks/list.go
@@ -8,6 +8,8 @@ import (
 	"text/tabwriter"
 	"text/template"
 
+	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/cmd/podman/validate"
 	"github.com/containers/podman/v2/libpod/network"
@@ -30,8 +32,6 @@ var (
 
 var (
 	networkListOptions entities.NetworkListOptions
-	headers            = "NAME\tVERSION\tPLUGINS\n"
-	defaultListRow     = "{{.Name}}\t{{.Version}}\t{{.Plugins}}\n"
 )
 
 func networkListFlags(flags *pflag.FlagSet) {
@@ -66,13 +66,12 @@ func networkList(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	// quiet means we only print the network names
-	if networkListOptions.Quiet {
-		return quietOut(responses)
-	}
-
-	if strings.ToLower(networkListOptions.Format) == "json" {
+	switch {
+	case report.IsJSON(networkListOptions.Format):
 		return jsonOut(responses)
+	case networkListOptions.Quiet:
+		// quiet means we only print the network names
+		return quietOut(responses)
 	}
 
 	nlprs := make([]ListPrintReports, 0, len(responses))
@@ -80,27 +79,32 @@ func networkList(cmd *cobra.Command, args []string) error {
 		nlprs = append(nlprs, ListPrintReports{r})
 	}
 
-	row := networkListOptions.Format
-	if len(row) < 1 {
-		row = defaultListRow
-	}
-	if !strings.HasSuffix(row, "\n") {
-		row += "\n"
+	headers := report.Headers(ListPrintReports{}, map[string]string{
+		"CNIVersion": "version",
+		"Plugins":    "plugins",
+	})
+	renderHeaders := true
+	row := "{{.Name}}\t{{.Version}}\t{{.Plugins}}\n"
+	if cmd.Flags().Changed("format") {
+		renderHeaders = parse.HasTable(networkListOptions.Format)
+		row = report.NormalizeFormat(networkListOptions.Format)
 	}
+	format := parse.EnforceRange(row)
 
-	format := "{{range . }}" + row + "{{end}}"
-	if !cmd.Flag("format").Changed {
-		format = headers + format
-	}
 	tmpl, err := template.New("listNetworks").Parse(format)
 	if err != nil {
 		return err
 	}
 	w := tabwriter.NewWriter(os.Stdout, 8, 2, 2, ' ', 0)
-	if err := tmpl.Execute(w, nlprs); err != nil {
-		return err
+	defer w.Flush()
+
+	if renderHeaders {
+		if err := tmpl.Execute(w, headers); err != nil {
+			return err
+		}
+
 	}
-	return w.Flush()
+	return tmpl.Execute(w, nlprs)
 }
 
 func quietOut(responses []*entities.NetworkListReport) error {
diff --git a/cmd/podman/parse/template.go b/cmd/podman/parse/template.go
new file mode 100644
index 000000000..0b80f1b3a
--- /dev/null
+++ b/cmd/podman/parse/template.go
@@ -0,0 +1,22 @@
+package parse
+
+import (
+	"regexp"
+	"strings"
+)
+
+var rangeRegex = regexp.MustCompile(`{{\s*range\s*\.\s*}}.*{{\s*end\s*}}`)
+
+// TODO move to github.com/containers/common/pkg/report
+// EnforceRange ensures that the format string contains a range
+func EnforceRange(format string) string {
+	if !rangeRegex.MatchString(format) {
+		return "{{range .}}" + format + "{{end}}"
+	}
+	return format
+}
+
+// EnforceRange ensures that the format string contains a range
+func HasTable(format string) bool {
+	return strings.HasPrefix(format, "table ")
+}
diff --git a/cmd/podman/parse/template_test.go b/cmd/podman/parse/template_test.go
new file mode 100644
index 000000000..7880d9bec
--- /dev/null
+++ b/cmd/podman/parse/template_test.go
@@ -0,0 +1,30 @@
+package parse
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEnforceRange(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"{{range .}}{{.ID}}{{end}}", "{{range .}}{{.ID}}{{end}}"},
+		{"{{.ID}}", "{{range .}}{{.ID}}{{end}}"},
+		{"{{ range . }}{{ .ID }}{{ end }}", "{{ range . }}{{ .ID }}{{ end }}"},
+		// EnforceRange does not verify syntax or semantics, that will happen later
+		{"{{range .}}{{.ID}}", "{{range .}}{{range .}}{{.ID}}{{end}}"},
+		{".ID", "{{range .}}.ID{{end}}"},
+	}
+
+	for _, tc := range tests {
+		tc := tc
+		label := "TestEnforceRange_" + tc.input
+		t.Run(label, func(t *testing.T) {
+			t.Parallel()
+			assert.Equal(t, tc.expected, EnforceRange(tc.input))
+		})
+	}
+}
diff --git a/cmd/podman/pods/ps.go b/cmd/podman/pods/ps.go
index 688108c1a..40fc71780 100644
--- a/cmd/podman/pods/ps.go
+++ b/cmd/podman/pods/ps.go
@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/cmd/podman/validate"
 	"github.com/containers/podman/v2/pkg/domain/entities"
@@ -113,20 +114,22 @@ func pods(cmd *cobra.Command, _ []string) error {
 		"Created":            "CREATED",
 		"InfraID":            "INFRA ID",
 	})
+	renderHeaders := true
 	row := podPsFormat()
 	if cmd.Flags().Changed("format") {
+		renderHeaders = parse.HasTable(psInput.Format)
 		row = report.NormalizeFormat(psInput.Format)
 	}
-	row = "{{range . }}" + row + "{{end}}"
+	format := parse.EnforceRange(row)
 
-	tmpl, err := template.New("listPods").Parse(row)
+	tmpl, err := template.New("listPods").Parse(format)
 	if err != nil {
 		return err
 	}
 	w := tabwriter.NewWriter(os.Stdout, 8, 2, 2, ' ', 0)
 	defer w.Flush()
 
-	if !psInput.Quiet && !cmd.Flag("format").Changed {
+	if renderHeaders {
 		if err := tmpl.Execute(w, headers); err != nil {
 			return err
 		}
diff --git a/cmd/podman/pods/stats.go b/cmd/podman/pods/stats.go
index 338f13d3e..c5d1e7f07 100644
--- a/cmd/podman/pods/stats.go
+++ b/cmd/podman/pods/stats.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/buger/goterm"
 	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/cmd/podman/validate"
 	"github.com/containers/podman/v2/pkg/domain/entities"
@@ -135,7 +136,7 @@ func printFormattedPodStatsLines(headerNames []map[string]string, row string, st
 		return nil
 	}
 
-	row = "{{range .}}" + row + "{{end}}"
+	row = parse.EnforceRange(row)
 
 	tmpl, err := template.New("pod stats").Parse(row)
 	if err != nil {
diff --git a/cmd/podman/system/df.go b/cmd/podman/system/df.go
index b11167938..fbdf274fb 100644
--- a/cmd/podman/system/df.go
+++ b/cmd/podman/system/df.go
@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/cmd/podman/validate"
 	"github.com/containers/podman/v2/pkg/domain/entities"
@@ -55,7 +56,7 @@ func df(cmd *cobra.Command, args []string) error {
 	w := tabwriter.NewWriter(os.Stdout, 8, 2, 2, ' ', 0)
 
 	if dfOptions.Verbose {
-		return printVerbose(cmd, w, reports)
+		return printVerbose(w, cmd, reports)
 	}
 	return printSummary(w, cmd, reports)
 }
@@ -131,20 +132,16 @@ func printSummary(w *tabwriter.Writer, cmd *cobra.Command, reports *entities.Sys
 		"Size":        "SIZE",
 		"Reclaimable": "RECLAIMABLE",
 	})
-
 	row := "{{.Type}}\t{{.Total}}\t{{.Active}}\t{{.Size}}\t{{.Reclaimable}}\n"
 	if cmd.Flags().Changed("format") {
 		row = report.NormalizeFormat(dfOptions.Format)
 	}
-	row = "{{range . }}" + row + "{{end}}"
-
-	return writeTemplate(cmd, w, hdrs, row, dfSummaries)
+	return writeTemplate(w, cmd, hdrs, row, dfSummaries)
 }
 
-func printVerbose(cmd *cobra.Command, w *tabwriter.Writer, reports *entities.SystemDfReport) error {
+func printVerbose(w *tabwriter.Writer, cmd *cobra.Command, reports *entities.SystemDfReport) error {
 	defer w.Flush()
 
-	// Images
 	fmt.Fprint(w, "Images space usage:\n\n")
 	// convert to dfImage for output
 	dfImages := make([]*dfImage, 0, len(reports.Images))
@@ -157,14 +154,11 @@ func printVerbose(cmd *cobra.Command, w *tabwriter.Writer, reports *entities.Sys
 		"UniqueSize": "UNIQUE SIZE",
 	})
 	imageRow := "{{.Repository}}\t{{.Tag}}\t{{.ImageID}}\t{{.Created}}\t{{.Size}}\t{{.SharedSize}}\t{{.UniqueSize}}\t{{.Containers}}\n"
-	format := "{{range . }}" + imageRow + "{{end}}"
-	if err := writeTemplate(cmd, w, hdrs, format, dfImages); err != nil {
+	if err := writeTemplate(w, cmd, hdrs, imageRow, dfImages); err != nil {
 		return nil
 	}
 
-	// Containers
 	fmt.Fprint(w, "\nContainers space usage:\n\n")
-
 	// convert to dfContainers for output
 	dfContainers := make([]*dfContainer, 0, len(reports.Containers))
 	for _, d := range reports.Containers {
@@ -176,14 +170,11 @@ func printVerbose(cmd *cobra.Command, w *tabwriter.Writer, reports *entities.Sys
 		"RWSize":       "SIZE",
 	})
 	containerRow := "{{.ContainerID}}\t{{.Image}}\t{{.Command}}\t{{.LocalVolumes}}\t{{.RWSize}}\t{{.Created}}\t{{.Status}}\t{{.Names}}\n"
-	format = "{{range . }}" + containerRow + "{{end}}"
-	if err := writeTemplate(cmd, w, hdrs, format, dfContainers); err != nil {
+	if err := writeTemplate(w, cmd, hdrs, containerRow, dfContainers); err != nil {
 		return nil
 	}
 
-	// Volumes
 	fmt.Fprint(w, "\nLocal Volumes space usage:\n\n")
-
 	dfVolumes := make([]*dfVolume, 0, len(reports.Volumes))
 	// convert to dfVolume for output
 	for _, d := range reports.Volumes {
@@ -193,14 +184,13 @@ func printVerbose(cmd *cobra.Command, w *tabwriter.Writer, reports *entities.Sys
 		"VolumeName": "VOLUME NAME",
 	})
 	volumeRow := "{{.VolumeName}}\t{{.Links}}\t{{.Size}}\n"
-	format = "{{range . }}" + volumeRow + "{{end}}"
-	return writeTemplate(cmd, w, hdrs, format, dfVolumes)
+	return writeTemplate(w, cmd, hdrs, volumeRow, dfVolumes)
 }
 
-func writeTemplate(cmd *cobra.Command, w *tabwriter.Writer, hdrs []map[string]string, format string,
-	output interface{}) error {
+func writeTemplate(w *tabwriter.Writer, cmd *cobra.Command, hdrs []map[string]string, format string, output interface{}) error {
 	defer w.Flush()
 
+	format = parse.EnforceRange(format)
 	tmpl, err := template.New("df").Parse(format)
 	if err != nil {
 		return err
diff --git a/cmd/podman/volumes/list.go b/cmd/podman/volumes/list.go
index b3b2b8ea1..ce0b7997d 100644
--- a/cmd/podman/volumes/list.go
+++ b/cmd/podman/volumes/list.go
@@ -9,6 +9,7 @@ import (
 	"text/template"
 
 	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v2/cmd/podman/parse"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/cmd/podman/validate"
 	"github.com/containers/podman/v2/pkg/domain/entities"
@@ -91,9 +92,9 @@ func outputTemplate(cmd *cobra.Command, responses []*entities.VolumeListReport)
 	if cliOpts.Quiet {
 		row = "{{.Name}}\n"
 	}
-	row = "{{range . }}" + row + "{{end}}"
+	format := parse.EnforceRange(row)
 
-	tmpl, err := template.New("list volume").Parse(row)
+	tmpl, err := template.New("list volume").Parse(format)
 	if err != nil {
 		return err
 	}