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, 26 insertions, 9 deletions

diff --git a/cmd/podman/containers/runlabel.go b/cmd/podman/containers/runlabel.go
index 92581c26f..2f6d2eb05 100644
--- a/cmd/podman/containers/runlabel.go
+++ b/cmd/podman/containers/runlabel.go
@@ -5,7 +5,9 @@ import (
 	"os"
 
 	"github.com/containers/common/pkg/auth"
+	"github.com/containers/common/pkg/completion"
 	"github.com/containers/image/v5/types"
+	"github.com/containers/podman/v2/cmd/podman/common"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/pkg/domain/entities"
 	"github.com/sirupsen/logrus"
@@ -23,11 +25,12 @@ var (
 	runlabelOptions     = runlabelOptionsWrapper{}
 	runlabelDescription = "Executes a command as described by a container image label."
 	runlabelCommand     = &cobra.Command{
-		Use:   "runlabel [options] LABEL IMAGE [ARG...]",
-		Short: "Execute the command described by an image label",
-		Long:  runlabelDescription,
-		RunE:  runlabel,
-		Args:  cobra.MinimumNArgs(2),
+		Use:               "runlabel [options] LABEL IMAGE [ARG...]",
+		Short:             "Execute the command described by an image label",
+		Long:              runlabelDescription,
+		RunE:              runlabel,
+		Args:              cobra.MinimumNArgs(2),
+		ValidArgsFunction: common.AutocompleteImages,
 		Example: `podman container runlabel run imageID
   podman container runlabel install imageID arg1 arg2
   podman container runlabel --display run myImage`,
@@ -42,11 +45,25 @@ func init() {
 	})
 
 	flags := runlabelCommand.Flags()
-	flags.StringVar(&runlabelOptions.Authfile, "authfile", auth.GetDefaultAuthFile(), "Path of the authentication file. Use REGISTRY_AUTH_FILE environment variable to override")
-	flags.StringVar(&runlabelOptions.CertDir, "cert-dir", "", "`Pathname` of a directory containing TLS certificates and keys")
-	flags.StringVar(&runlabelOptions.Credentials, "creds", "", "`Credentials` (USERNAME:PASSWORD) to use for authenticating to a registry")
+
+	authfileflagName := "authfile"
+	flags.StringVar(&runlabelOptions.Authfile, authfileflagName, auth.GetDefaultAuthFile(), "Path of the authentication file. Use REGISTRY_AUTH_FILE environment variable to override")
+	_ = runlabelCommand.RegisterFlagCompletionFunc(authfileflagName, completion.AutocompleteDefault)
+
+	certDirFlagName := "cert-dir"
+	flags.StringVar(&runlabelOptions.CertDir, certDirFlagName, "", "`Pathname` of a directory containing TLS certificates and keys")
+	_ = runlabelCommand.RegisterFlagCompletionFunc(certDirFlagName, completion.AutocompleteDefault)
+
+	credsFlagName := "creds"
+	flags.StringVar(&runlabelOptions.Credentials, credsFlagName, "", "`Credentials` (USERNAME:PASSWORD) to use for authenticating to a registry")
+	_ = runlabelCommand.RegisterFlagCompletionFunc(credsFlagName, completion.AutocompleteNone)
+
 	flags.BoolVar(&runlabelOptions.Display, "display", false, "Preview the command that the label would run")
-	flags.StringVarP(&runlabelOptions.Name, "name", "n", "", "Assign a name to the container")
+
+	nameFlagName := "name"
+	flags.StringVarP(&runlabelOptions.Name, nameFlagName, "n", "", "Assign a name to the container")
+	_ = runlabelCommand.RegisterFlagCompletionFunc(nameFlagName, completion.AutocompleteNone)
+
 	flags.StringVar(&runlabelOptions.Optional1, "opt1", "", "Optional parameter to pass for install")
 	flags.StringVar(&runlabelOptions.Optional2, "opt2", "", "Optional parameter to pass for install")
 	flags.StringVar(&runlabelOptions.Optional3, "opt3", "", "Optional parameter to pass for install")