Add go template shell completion for --format

The --format flags accepts go template strings. I use this often but I
consistently forget the field names. This commit adds a way to provide
shell completion for the --format flag. It works by automatically
receiving the field names with the reflect package from the given
struct. This requires almost no maintenance since this ensures that we
always use the correct field names. This also works for nested structs.

```
$ podman ps --format "{{.P"
{{.Pid}}      {{.PIDNS}}    {{.Pod}}      {{.PodName}}  {{.Ports}}
```

NOTE: This only works when you use quotes otherwise the shell does not
provide completions. Also this does not work for fish at the moment.

Signed-off-by: Paul Holzinger <paul.holzinger@web.de>

26 files changed, 257 insertions, 28 deletions

diff --git a/cmd/podman/common/completion.go b/cmd/podman/common/completion.go
index 6086df297..4aca79770 100644
--- a/cmd/podman/common/completion.go
+++ b/cmd/podman/common/completion.go
@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"fmt"
 	"os"
+	"reflect"
 	"strings"
 
 	"github.com/containers/common/pkg/config"
@@ -891,10 +892,85 @@ func AutocompleteNetworkFlag(cmd *cobra.Command, args []string, toComplete strin
 	return append(networks, suggestions...), dir
 }
 
-// AutocompleteJSONFormat - Autocomplete format flag option.
-// -> "json"
-func AutocompleteJSONFormat(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
-	return []string{"json"}, cobra.ShellCompDirectiveNoFileComp
+// AutocompleteFormat - Autocomplete json or a given struct to use for a go template.
+// The input can be nil, In this case only json will be autocompleted.
+// This function will only work for structs other types are not supported.
+// When "{{." is typed the field and method names of the given struct will be completed.
+// This also works recursive for nested structs.
+func AutocompleteFormat(o interface{}) func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+	// this function provides shell completion for go templates
+	return func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+		// autocomplete json when nothing or json is typed
+		if strings.HasPrefix("json", toComplete) {
+			return []string{"json"}, cobra.ShellCompDirectiveNoFileComp
+		}
+		// no input struct we cannot provide completion return nothing
+		if o == nil {
+			return nil, cobra.ShellCompDirectiveNoFileComp
+		}
+
+		// toComplete could look like this: {{ .Config }} {{ .Field.F
+		// 1. split the template variable delimiter
+		vars := strings.Split(toComplete, "{{")
+		if len(vars) == 1 {
+			// no variables return no completion
+			return nil, cobra.ShellCompDirectiveNoFileComp
+		}
+		// clean the spaces from the last var
+		field := strings.Split(vars[len(vars)-1], " ")
+		// split this into it struct field names
+		fields := strings.Split(field[len(field)-1], ".")
+		f := reflect.ValueOf(o)
+		for i := 1; i < len(fields); i++ {
+			if f.Kind() == reflect.Ptr {
+				f = f.Elem()
+			}
+
+			// // the only supported type is struct
+			if f.Kind() != reflect.Struct {
+				return nil, cobra.ShellCompDirectiveNoFileComp
+			}
+
+			// last field get all names to suggest
+			if i == len(fields)-1 {
+				suggestions := []string{}
+				for j := 0; j < f.NumField(); j++ {
+					fname := f.Type().Field(j).Name
+					suffix := "}}"
+					kind := f.Type().Field(j).Type.Kind()
+					if kind == reflect.Ptr {
+						// make sure to read the actual type when it is a pointer
+						kind = f.Type().Field(j).Type.Elem().Kind()
+					}
+					// when we have a nested struct do not append braces instead append a dot
+					if kind == reflect.Struct {
+						suffix = "."
+					}
+					if strings.HasPrefix(fname, fields[i]) {
+						// add field name with closing braces
+						suggestions = append(suggestions, fname+suffix)
+					}
+				}
+
+				for j := 0; j < f.NumMethod(); j++ {
+					fname := f.Type().Method(j).Name
+					if strings.HasPrefix(fname, fields[i]) {
+						// add method name with closing braces
+						suggestions = append(suggestions, fname+"}}")
+					}
+				}
+
+				// add the current toComplete value in front so that the shell can complete this correctly
+				toCompArr := strings.Split(toComplete, ".")
+				toCompArr[len(toCompArr)-1] = ""
+				toComplete = strings.Join(toCompArr, ".")
+				return prefixSlice(toComplete, suggestions), cobra.ShellCompDirectiveNoSpace | cobra.ShellCompDirectiveNoFileComp
+			}
+			// set the next struct field
+			f = f.FieldByName(fields[i])
+		}
+		return nil, cobra.ShellCompDirectiveNoFileComp
+	}
 }
 
 // AutocompleteEventFilter - Autocomplete event filter flag options.
diff --git a/cmd/podman/common/completion_test.go b/cmd/podman/common/completion_test.go
new file mode 100644
index 000000000..5bd627b85
--- /dev/null
+++ b/cmd/podman/common/completion_test.go
@@ -0,0 +1,142 @@
+package common_test
+
+import (
+	"testing"
+
+	"github.com/containers/podman/v3/cmd/podman/common"
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/assert"
+)
+
+type Car struct {
+	Brand string
+	Stats struct {
+		HP           *int
+		Displacement int
+	}
+	Extras map[string]string
+}
+
+func (c Car) Type() string {
+	return ""
+}
+
+func (c Car) Color() string {
+	return ""
+}
+
+func TestAutocompleteFormat(t *testing.T) {
+	testStruct := struct {
+		Name string
+		Age  int
+		Car  *Car
+	}{}
+
+	testStruct.Car = &Car{}
+	testStruct.Car.Extras = map[string]string{"test": "1"}
+
+	tests := []struct {
+		name       string
+		toComplete string
+		expected   []string
+	}{
+		{
+			"empty completion",
+			"",
+			[]string{"json"},
+		},
+		{
+			"json completion",
+			"json",
+			[]string{"json"},
+		},
+		{
+			"invalid completion",
+			"blahblah",
+			nil,
+		},
+		{
+			"invalid completion",
+			"{{",
+			nil,
+		},
+		{
+			"invalid completion",
+			"{{  ",
+			nil,
+		},
+		{
+			"invalid completion",
+			"{{  ..",
+			nil,
+		},
+		{
+			"fist level struct field name",
+			"{{.",
+			[]string{"{{.Name}}", "{{.Age}}", "{{.Car."},
+		},
+		{
+			"fist level struct field name",
+			"{{ .",
+			[]string{"{{ .Name}}", "{{ .Age}}", "{{ .Car."},
+		},
+		{
+			"fist level struct field name",
+			"{{ .N",
+			[]string{"{{ .Name}}"},
+		},
+		{
+			"second level struct field name",
+			"{{ .Car.",
+			[]string{"{{ .Car.Brand}}", "{{ .Car.Stats.", "{{ .Car.Extras}}", "{{ .Car.Color}}", "{{ .Car.Type}}"},
+		},
+		{
+			"second level struct field name",
+			"{{ .Car.B",
+			[]string{"{{ .Car.Brand}}"},
+		},
+		{
+			"three level struct field name",
+			"{{ .Car.Stats.",
+			[]string{"{{ .Car.Stats.HP}}", "{{ .Car.Stats.Displacement}}"},
+		},
+		{
+			"three level struct field name",
+			"{{ .Car.Stats.D",
+			[]string{"{{ .Car.Stats.Displacement}}"},
+		},
+		{
+			"second level struct field name",
+			"{{ .Car.B",
+			[]string{"{{ .Car.Brand}}"},
+		},
+		{
+			"invalid field name",
+			"{{ .Ca.B",
+			nil,
+		},
+		{
+			"map key names don't work",
+			"{{ .Car.Extras.",
+			nil,
+		},
+		{
+			"two variables struct field name",
+			"{{ .Car.Brand }} {{ .Car.",
+			[]string{"{{ .Car.Brand }} {{ .Car.Brand}}", "{{ .Car.Brand }} {{ .Car.Stats.", "{{ .Car.Brand }} {{ .Car.Extras}}",
+				"{{ .Car.Brand }} {{ .Car.Color}}", "{{ .Car.Brand }} {{ .Car.Type}}"},
+		},
+		{
+			"only dot without variable",
+			".",
+			nil,
+		},
+	}
+
+	for _, test := range tests {
+		completion, directive := common.AutocompleteFormat(testStruct)(nil, nil, test.toComplete)
+		// directive should always be greater than ShellCompDirectiveNoFileComp
+		assert.GreaterOrEqual(t, directive, cobra.ShellCompDirectiveNoFileComp, "unexpected ShellCompDirective")
+		assert.Equal(t, test.expected, completion, test.name)
+	}
+}
diff --git a/cmd/podman/containers/diff.go b/cmd/podman/containers/diff.go
index f6f262066..799d01127 100644
--- a/cmd/podman/containers/diff.go
+++ b/cmd/podman/containers/diff.go
@@ -39,7 +39,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVar(&diffOpts.Format, formatFlagName, "", "Change the output format")
-	_ = diffCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = diffCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 
 	validate.AddLatestFlag(diffCmd, &diffOpts.Latest)
 }
diff --git a/cmd/podman/containers/inspect.go b/cmd/podman/containers/inspect.go
index e7921fc39..eb29b7285 100644
--- a/cmd/podman/containers/inspect.go
+++ b/cmd/podman/containers/inspect.go
@@ -5,6 +5,7 @@ import (
 	"github.com/containers/podman/v3/cmd/podman/inspect"
 	"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/spf13/cobra"
 )
@@ -35,7 +36,12 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVarP(&inspectOpts.Format, formatFlagName, "f", "json", "Format the output to a Go template or json")
-	_ = inspectCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = inspectCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(define.InspectContainerData{
+		State:           &define.InspectContainerState{},
+		NetworkSettings: &define.InspectNetworkSettings{},
+		Config:          &define.InspectContainerConfig{},
+		HostConfig:      &define.InspectContainerHostConfig{},
+	}))
 
 	validate.AddLatestFlag(inspectCmd, &inspectOpts.Latest)
 }
diff --git a/cmd/podman/containers/mount.go b/cmd/podman/containers/mount.go
index 7853bfae6..fd5a279d2 100644
--- a/cmd/podman/containers/mount.go
+++ b/cmd/podman/containers/mount.go
@@ -61,7 +61,7 @@ func mountFlags(cmd *cobra.Command) {
 
 	formatFlagName := "format"
 	flags.StringVar(&mountOpts.Format, formatFlagName, "", "Print the mounted containers in specified format (json)")
-	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 
 	flags.BoolVar(&mountOpts.NoTruncate, "notruncate", false, "Do not truncate output")
 }
diff --git a/cmd/podman/containers/ps.go b/cmd/podman/containers/ps.go
index 97451eb46..3c0162676 100644
--- a/cmd/podman/containers/ps.go
+++ b/cmd/podman/containers/ps.go
@@ -87,7 +87,7 @@ func listFlagSet(cmd *cobra.Command) {
 
 	formatFlagName := "format"
 	flags.StringVar(&listOpts.Format, formatFlagName, "", "Pretty-print containers to JSON or using a Go template")
-	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(entities.ListContainer{}))
 
 	lastFlagName := "last"
 	flags.IntVarP(&listOpts.Last, lastFlagName, "n", -1, "Print the n last created containers (all states)")
diff --git a/cmd/podman/containers/stats.go b/cmd/podman/containers/stats.go
index 4c31896be..7160f1ba8 100644
--- a/cmd/podman/containers/stats.go
+++ b/cmd/podman/containers/stats.go
@@ -71,7 +71,7 @@ func statFlags(cmd *cobra.Command) {
 
 	formatFlagName := "format"
 	flags.StringVar(&statsOptions.Format, formatFlagName, "", "Pretty-print container statistics to JSON or using a Go template")
-	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(define.ContainerStats{}))
 
 	flags.BoolVar(&statsOptions.NoReset, "no-reset", false, "Disable resetting the screen between intervals")
 	flags.BoolVar(&statsOptions.NoStream, "no-stream", false, "Disable streaming stats and only pull the first result, default setting is false")
diff --git a/cmd/podman/diff.go b/cmd/podman/diff.go
index 4862d31b5..ae7d6c4bc 100644
--- a/cmd/podman/diff.go
+++ b/cmd/podman/diff.go
@@ -43,7 +43,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVar(&diffOpts.Format, formatFlagName, "", "Change the output format")
-	_ = diffCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = diffCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 
 	validate.AddLatestFlag(diffCmd, &diffOpts.Latest)
 }
diff --git a/cmd/podman/generate/systemd.go b/cmd/podman/generate/systemd.go
index 693506725..72b2e6335 100644
--- a/cmd/podman/generate/systemd.go
+++ b/cmd/podman/generate/systemd.go
@@ -72,7 +72,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVar(&format, formatFlagName, "", "Print the created units in specified format (json)")
-	_ = systemdCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = systemdCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 
 	flags.SetNormalizeFunc(utils.AliasFlags)
 }
diff --git a/cmd/podman/images/diff.go b/cmd/podman/images/diff.go
index 36b0d4e7a..7f4c3e83d 100644
--- a/cmd/podman/images/diff.go
+++ b/cmd/podman/images/diff.go
@@ -41,7 +41,7 @@ func diffFlags(flags *pflag.FlagSet) {
 
 	formatFlagName := "format"
 	flags.StringVar(&diffOpts.Format, formatFlagName, "", "Change the output format")
-	_ = diffCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = diffCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 }
 
 func diff(cmd *cobra.Command, args []string) error {
diff --git a/cmd/podman/images/history.go b/cmd/podman/images/history.go
index eaf56651f..16be0bb19 100644
--- a/cmd/podman/images/history.go
+++ b/cmd/podman/images/history.go
@@ -74,7 +74,7 @@ func historyFlags(cmd *cobra.Command) {
 
 	formatFlagName := "format"
 	flags.StringVar(&opts.format, formatFlagName, "", "Change the output to JSON or a Go template")
-	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(entities.ImageHistoryLayer{}))
 
 	flags.BoolVarP(&opts.human, "human", "H", true, "Display sizes and dates in human readable format")
 	flags.BoolVar(&opts.noTrunc, "no-trunc", false, "Do not truncate the output")
diff --git a/cmd/podman/images/inspect.go b/cmd/podman/images/inspect.go
index fb96286fa..ac3becaa6 100644
--- a/cmd/podman/images/inspect.go
+++ b/cmd/podman/images/inspect.go
@@ -5,6 +5,7 @@ import (
 	"github.com/containers/podman/v3/cmd/podman/inspect"
 	"github.com/containers/podman/v3/cmd/podman/registry"
 	"github.com/containers/podman/v3/pkg/domain/entities"
+	inspectTypes "github.com/containers/podman/v3/pkg/inspect"
 	"github.com/spf13/cobra"
 )
 
@@ -34,7 +35,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVarP(&inspectOpts.Format, formatFlagName, "f", "json", "Format the output to a Go template or json")
-	_ = inspectCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = inspectCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(inspectTypes.ImageData{}))
 }
 
 func inspectExec(cmd *cobra.Command, args []string) error {
diff --git a/cmd/podman/images/list.go b/cmd/podman/images/list.go
index 7a9a8a804..132af858b 100644
--- a/cmd/podman/images/list.go
+++ b/cmd/podman/images/list.go
@@ -83,7 +83,7 @@ func imageListFlagSet(cmd *cobra.Command) {
 
 	formatFlagName := "format"
 	flags.StringVar(&listFlag.format, formatFlagName, "", "Change the output format to JSON or a Go template")
-	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(entities.ImageSummary{}))
 
 	flags.BoolVar(&listFlag.digests, "digests", false, "Show digests")
 	flags.BoolVarP(&listFlag.noHeading, "noheading", "n", false, "Do not print column headings")
diff --git a/cmd/podman/images/mount.go b/cmd/podman/images/mount.go
index 79c97006d..a098aac63 100644
--- a/cmd/podman/images/mount.go
+++ b/cmd/podman/images/mount.go
@@ -51,7 +51,7 @@ func mountFlags(cmd *cobra.Command) {
 
 	formatFlagName := "format"
 	flags.StringVar(&mountOpts.Format, formatFlagName, "", "Print the mounted images in specified format (json)")
-	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 }
 
 func init() {
diff --git a/cmd/podman/networks/inspect.go b/cmd/podman/networks/inspect.go
index 953f5e6e8..a05b9026d 100644
--- a/cmd/podman/networks/inspect.go
+++ b/cmd/podman/networks/inspect.go
@@ -33,7 +33,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVarP(&inspectOpts.Format, formatFlagName, "f", "", "Pretty-print network to JSON or using a Go template")
-	_ = networkinspectCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = networkinspectCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 }
 
 func networkInspect(_ *cobra.Command, args []string) error {
diff --git a/cmd/podman/networks/list.go b/cmd/podman/networks/list.go
index bc100da8c..e1b182cbf 100644
--- a/cmd/podman/networks/list.go
+++ b/cmd/podman/networks/list.go
@@ -41,7 +41,7 @@ var (
 func networkListFlags(flags *pflag.FlagSet) {
 	formatFlagName := "format"
 	flags.StringVar(&networkListOptions.Format, formatFlagName, "", "Pretty-print networks to JSON or using a Go template")
-	_ = networklistCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = networklistCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(ListPrintReports{}))
 
 	flags.BoolVarP(&networkListOptions.Quiet, "quiet", "q", false, "display only names")
 	flags.BoolVar(&noTrunc, "no-trunc", false, "Do not truncate the network ID")
diff --git a/cmd/podman/pods/inspect.go b/cmd/podman/pods/inspect.go
index 96e007fa3..c66b81adb 100644
--- a/cmd/podman/pods/inspect.go
+++ b/cmd/podman/pods/inspect.go
@@ -10,6 +10,7 @@ import (
 	"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/pkg/errors"
 	"github.com/spf13/cobra"
@@ -44,7 +45,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVarP(&inspectOptions.Format, formatFlagName, "f", "json", "Format the output to a Go template or json")
-	_ = inspectCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = inspectCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(define.InspectPodData{}))
 
 	validate.AddLatestFlag(inspectCmd, &inspectOptions.Latest)
 }
diff --git a/cmd/podman/pods/ps.go b/cmd/podman/pods/ps.go
index a4b6d1afa..beaeda871 100644
--- a/cmd/podman/pods/ps.go
+++ b/cmd/podman/pods/ps.go
@@ -61,7 +61,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVar(&psInput.Format, formatFlagName, "", "Pretty-print pods to JSON or using a Go template")
-	_ = psCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = psCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(ListPodReporter{}))
 
 	flags.Bool("noheading", false, "Do not print headers")
 	flags.BoolVar(&psInput.Namespace, "namespace", false, "Display namespace information of the pod")
diff --git a/cmd/podman/pods/stats.go b/cmd/podman/pods/stats.go
index e336b864e..97147275e 100644
--- a/cmd/podman/pods/stats.go
+++ b/cmd/podman/pods/stats.go
@@ -58,7 +58,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVar(&statsOptions.Format, formatFlagName, "", "Pretty-print container statistics to JSON or using a Go template")
-	_ = statsCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = statsCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(entities.PodStatsReport{}))
 
 	flags.BoolVar(&statsOptions.NoReset, "no-reset", false, "Disable resetting the screen when streaming")
 	flags.BoolVar(&statsOptions.NoStream, "no-stream", false, "Disable streaming stats and only pull the first result")
diff --git a/cmd/podman/secrets/inspect.go b/cmd/podman/secrets/inspect.go
index 4036291ec..bcb1adb5e 100644
--- a/cmd/podman/secrets/inspect.go
+++ b/cmd/podman/secrets/inspect.go
@@ -40,7 +40,7 @@ func init() {
 	flags := inspectCmd.Flags()
 	formatFlagName := "format"
 	flags.StringVar(&format, formatFlagName, "", "Format volume output using Go template")
-	_ = inspectCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = inspectCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(entities.SecretInfoReport{}))
 }
 
 func inspect(cmd *cobra.Command, args []string) error {
diff --git a/cmd/podman/secrets/list.go b/cmd/podman/secrets/list.go
index 2006fb0ee..ba7065d61 100644
--- a/cmd/podman/secrets/list.go
+++ b/cmd/podman/secrets/list.go
@@ -47,7 +47,7 @@ func init() {
 	flags := lsCmd.Flags()
 	formatFlagName := "format"
 	flags.StringVar(&listFlag.format, formatFlagName, "{{.ID}}\t{{.Name}}\t{{.Driver}}\t{{.CreatedAt}}\t{{.UpdatedAt}}\t\n", "Format volume output using Go template")
-	_ = lsCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = lsCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(entities.SecretInfoReport{}))
 	flags.BoolVar(&listFlag.noHeading, "noheading", false, "Do not print headers")
 }
 
diff --git a/cmd/podman/system/events.go b/cmd/podman/system/events.go
index 0f52282a9..568610bdc 100644
--- a/cmd/podman/system/events.go
+++ b/cmd/podman/system/events.go
@@ -52,7 +52,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVar(&eventFormat, formatFlagName, "", "format the output using a Go template")
-	_ = eventsCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = eventsCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(events.Event{}))
 
 	flags.BoolVar(&eventOptions.Stream, "stream", true, "stream new events; for testing only")
 
diff --git a/cmd/podman/system/info.go b/cmd/podman/system/info.go
index 2babd49c8..afd5b3a34 100644
--- a/cmd/podman/system/info.go
+++ b/cmd/podman/system/info.go
@@ -10,6 +10,7 @@ import (
 	"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/ghodss/yaml"
 	"github.com/spf13/cobra"
@@ -68,7 +69,7 @@ func infoFlags(cmd *cobra.Command) {
 
 	formatFlagName := "format"
 	flags.StringVarP(&inFormat, formatFlagName, "f", "", "Change the output format to JSON or a Go template")
-	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(define.Info{Host: &define.HostInfo{}, Store: &define.StoreInfo{}}))
 }
 
 func info(cmd *cobra.Command, args []string) error {
diff --git a/cmd/podman/system/version.go b/cmd/podman/system/version.go
index dfb10c080..ad9fd2a85 100644
--- a/cmd/podman/system/version.go
+++ b/cmd/podman/system/version.go
@@ -38,7 +38,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVarP(&versionFormat, formatFlagName, "f", "", "Change the output format to JSON or a Go template")
-	_ = versionCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = versionCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(entities.SystemVersionReport{}))
 }
 
 func version(cmd *cobra.Command, args []string) error {
diff --git a/cmd/podman/volumes/inspect.go b/cmd/podman/volumes/inspect.go
index 91269e3d1..d52eee9f3 100644
--- a/cmd/podman/volumes/inspect.go
+++ b/cmd/podman/volumes/inspect.go
@@ -4,6 +4,7 @@ import (
 	"github.com/containers/podman/v3/cmd/podman/common"
 	"github.com/containers/podman/v3/cmd/podman/inspect"
 	"github.com/containers/podman/v3/cmd/podman/registry"
+	"github.com/containers/podman/v3/libpod/define"
 	"github.com/containers/podman/v3/pkg/domain/entities"
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
@@ -41,7 +42,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVarP(&inspectOpts.Format, formatFlagName, "f", "json", "Format volume output using Go template")
-	_ = inspectCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = inspectCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(define.InspectVolumeData{}))
 }
 
 func volumeInspect(cmd *cobra.Command, args []string) error {
diff --git a/cmd/podman/volumes/list.go b/cmd/podman/volumes/list.go
index 0d764e988..f402afa94 100644
--- a/cmd/podman/volumes/list.go
+++ b/cmd/podman/volumes/list.go
@@ -14,6 +14,7 @@ import (
 	"github.com/containers/podman/v3/cmd/podman/parse"
 	"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/pkg/errors"
 	"github.com/spf13/cobra"
@@ -60,7 +61,7 @@ func init() {
 
 	formatFlagName := "format"
 	flags.StringVar(&cliOpts.Format, formatFlagName, "{{.Driver}}\t{{.Name}}\n", "Format volume output using Go template")
-	_ = lsCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteJSONFormat)
+	_ = lsCommand.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(define.InspectVolumeData{}))
 
 	flags.Bool("noheading", false, "Do not print headers")
 	flags.BoolVarP(&cliOpts.Quiet, "quiet", "q", false, "Print volume output in quiet mode")