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>

2 files changed, 2 insertions, 2 deletions

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")
 }