Add shell completion with cobra

Allow automatic generation for shell completion scripts
with the internal cobra functions (requires v1.0.0+).

This should replace the handwritten completion scripts
and even adds support for fish. With this approach it is
less likley that completions and code are out of sync.

We can now create the scripts with
- podman completion bash
- podman completion zsh
- podman completion fish

To test the completion run:
source <(podman completion bash)

The same works for podman-remote and podman --remote and
it will complete your remote containers/images with
the correct endpoints values from --url/--connection.

The completion logic is written in go and provided by the
cobra library. The completion functions lives in
`cmd/podman/completion/completion.go`.

The unit test at cmd/podman/shell_completion_test.go checks
if each command and flag has an autocompletion function set.
This prevents that commands and flags have no shell completion set.

This commit does not replace the current autocompletion scripts.

Closes #6440

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

1 files changed, 37 insertions, 23 deletions

diff --git a/cmd/podman/images/search.go b/cmd/podman/images/search.go
index 7de6a7316..c2ef7d767 100644
--- a/cmd/podman/images/search.go
+++ b/cmd/podman/images/search.go
@@ -7,6 +7,7 @@ import (
 	"text/template"
 
 	"github.com/containers/common/pkg/auth"
+	"github.com/containers/common/pkg/completion"
 	"github.com/containers/common/pkg/report"
 	"github.com/containers/image/v5/types"
 	"github.com/containers/podman/v2/cmd/podman/parse"
@@ -14,7 +15,6 @@ import (
 	"github.com/containers/podman/v2/pkg/domain/entities"
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
-	"github.com/spf13/pflag"
 )
 
 // searchOptionsWrapper wraps entities.ImagePullOptions and prevents leaking
@@ -34,11 +34,12 @@ var (
 
 	// Command: podman search
 	searchCmd = &cobra.Command{
-		Use:   "search [options] TERM",
-		Short: "Search registry for image",
-		Long:  searchDescription,
-		RunE:  imageSearch,
-		Args:  cobra.ExactArgs(1),
+		Use:               "search [options] TERM",
+		Short:             "Search registry for image",
+		Long:              searchDescription,
+		RunE:              imageSearch,
+		Args:              cobra.ExactArgs(1),
+		ValidArgsFunction: completion.AutocompleteNone,
 		Example: `podman search --filter=is-official --limit 3 alpine
   podman search registry.fedoraproject.org/  # only works with v2 registries
   podman search --format "table {{.Index}} {{.Name}}" registry.fedoraproject.org/fedora`,
@@ -46,12 +47,13 @@ var (
 
 	// Command: podman image search
 	imageSearchCmd = &cobra.Command{
-		Use:         searchCmd.Use,
-		Short:       searchCmd.Short,
-		Long:        searchCmd.Long,
-		RunE:        searchCmd.RunE,
-		Args:        searchCmd.Args,
-		Annotations: searchCmd.Annotations,
+		Use:               searchCmd.Use,
+		Short:             searchCmd.Short,
+		Long:              searchCmd.Long,
+		RunE:              searchCmd.RunE,
+		Args:              searchCmd.Args,
+		Annotations:       searchCmd.Annotations,
+		ValidArgsFunction: searchCmd.ValidArgsFunction,
 		Example: `podman image search --filter=is-official --limit 3 alpine
   podman image search registry.fedoraproject.org/  # only works with v2 registries
   podman image search --format "table {{.Index}} {{.Name}}" registry.fedoraproject.org/fedora`,
@@ -64,9 +66,7 @@ func init() {
 		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
 		Command: searchCmd,
 	})
-
-	flags := searchCmd.Flags()
-	searchFlags(flags)
+	searchFlags(searchCmd)
 
 	// images search
 	registry.Commands = append(registry.Commands, registry.CliCommand{
@@ -74,18 +74,32 @@ func init() {
 		Command: imageSearchCmd,
 		Parent:  imageCmd,
 	})
-
-	imageSearchFlags := imageSearchCmd.Flags()
-	searchFlags(imageSearchFlags)
+	searchFlags(imageSearchCmd)
 }
 
 // searchFlags set the flags for the pull command.
-func searchFlags(flags *pflag.FlagSet) {
-	flags.StringSliceVarP(&searchOptions.Filters, "filter", "f", []string{}, "Filter output based on conditions provided (default [])")
-	flags.StringVar(&searchOptions.Format, "format", "", "Change the output format to JSON or a Go template")
-	flags.IntVar(&searchOptions.Limit, "limit", 0, "Limit the number of results")
+func searchFlags(cmd *cobra.Command) {
+	flags := cmd.Flags()
+
+	filterFlagName := "filter"
+	flags.StringSliceVarP(&searchOptions.Filters, filterFlagName, "f", []string{}, "Filter output based on conditions provided (default [])")
+	//TODO add custom filter function
+	_ = cmd.RegisterFlagCompletionFunc(filterFlagName, completion.AutocompleteNone)
+
+	formatFlagName := "format"
+	flags.StringVar(&searchOptions.Format, formatFlagName, "", "Change the output format to JSON or a Go template")
+	_ = cmd.RegisterFlagCompletionFunc(formatFlagName, completion.AutocompleteNone)
+
+	limitFlagName := "limit"
+	flags.IntVar(&searchOptions.Limit, limitFlagName, 0, "Limit the number of results")
+	_ = cmd.RegisterFlagCompletionFunc(limitFlagName, completion.AutocompleteNone)
+
 	flags.BoolVar(&searchOptions.NoTrunc, "no-trunc", false, "Do not truncate the output")
-	flags.StringVar(&searchOptions.Authfile, "authfile", auth.GetDefaultAuthFile(), "Path of the authentication file. Use REGISTRY_AUTH_FILE environment variable to override")
+
+	authfileFlagName := "authfile"
+	flags.StringVar(&searchOptions.Authfile, authfileFlagName, auth.GetDefaultAuthFile(), "Path of the authentication file. Use REGISTRY_AUTH_FILE environment variable to override")
+	_ = cmd.RegisterFlagCompletionFunc(authfileFlagName, completion.AutocompleteDefault)
+
 	flags.BoolVar(&searchOptions.TLSVerifyCLI, "tls-verify", true, "Require HTTPS and verify certificates when contacting registries")
 	flags.BoolVar(&searchOptions.ListTags, "list-tags", false, "List the tags of the input registry")
 }