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, 25 insertions, 14 deletions

diff --git a/cmd/podman/images/build.go b/cmd/podman/images/build.go
index f48d1cd94..b9aabe64e 100644
--- a/cmd/podman/images/build.go
+++ b/cmd/podman/images/build.go
@@ -9,6 +9,7 @@ import (
 	"github.com/containers/buildah/imagebuildah"
 	buildahCLI "github.com/containers/buildah/pkg/cli"
 	"github.com/containers/buildah/pkg/parse"
+	"github.com/containers/common/pkg/completion"
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/cmd/podman/utils"
@@ -18,7 +19,6 @@ import (
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
-	"github.com/spf13/pflag"
 )
 
 // buildFlagsWrapper are local to cmd/ as the build code is using Buildah-internal
@@ -40,22 +40,24 @@ var (
 	// Command: podman _diff_ Object_ID
 	buildDescription = "Builds an OCI or Docker image using instructions from one or more Containerfiles and a specified build context directory."
 	buildCmd         = &cobra.Command{
-		Use:   "build [options] [CONTEXT]",
-		Short: "Build an image using instructions from Containerfiles",
-		Long:  buildDescription,
-		Args:  cobra.MaximumNArgs(1),
-		RunE:  build,
+		Use:               "build [options] [CONTEXT]",
+		Short:             "Build an image using instructions from Containerfiles",
+		Long:              buildDescription,
+		Args:              cobra.MaximumNArgs(1),
+		RunE:              build,
+		ValidArgsFunction: completion.AutocompleteDefault,
 		Example: `podman build .
   podman build --creds=username:password -t imageName -f Containerfile.simple .
   podman build --layers --force-rm --tag imageName .`,
 	}
 
 	imageBuildCmd = &cobra.Command{
-		Args:  buildCmd.Args,
-		Use:   buildCmd.Use,
-		Short: buildCmd.Short,
-		Long:  buildCmd.Long,
-		RunE:  buildCmd.RunE,
+		Args:              buildCmd.Args,
+		Use:               buildCmd.Use,
+		Short:             buildCmd.Short,
+		Long:              buildCmd.Long,
+		RunE:              buildCmd.RunE,
+		ValidArgsFunction: buildCmd.ValidArgsFunction,
 		Example: `podman image build .
   podman image build --creds=username:password -t imageName -f Containerfile.simple .
   podman image build --layers --force-rm --tag imageName .`,
@@ -79,22 +81,25 @@ func init() {
 		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
 		Command: buildCmd,
 	})
-	buildFlags(buildCmd.Flags())
+	buildFlags(buildCmd)
 
 	registry.Commands = append(registry.Commands, registry.CliCommand{
 		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
 		Command: imageBuildCmd,
 		Parent:  imageCmd,
 	})
-	buildFlags(imageBuildCmd.Flags())
+	buildFlags(imageBuildCmd)
 }
 
-func buildFlags(flags *pflag.FlagSet) {
+func buildFlags(cmd *cobra.Command) {
+	flags := cmd.Flags()
+
 	// Podman flags
 	flags.BoolVarP(&buildOpts.SquashAll, "squash-all", "", false, "Squash all layers into a single layer")
 
 	// Bud flags
 	budFlags := buildahCLI.GetBudFlags(&buildOpts.BudResults)
+
 	// --pull flag
 	flag := budFlags.Lookup("pull")
 	if err := flag.Value.Set("true"); err != nil {
@@ -102,6 +107,9 @@ func buildFlags(flags *pflag.FlagSet) {
 	}
 	flag.DefValue = "true"
 	flags.AddFlagSet(&budFlags)
+	// Add the completion functions
+	budCompletions := buildahCLI.GetBudFlagsCompletions()
+	completion.CompleteCommandFlags(cmd, budCompletions)
 
 	// Layer flags
 	layerFlags := buildahCLI.GetLayerFlags(&buildOpts.LayerResults)
@@ -127,6 +135,9 @@ func buildFlags(flags *pflag.FlagSet) {
 		os.Exit(1)
 	}
 	flags.AddFlagSet(&fromAndBudFlags)
+	// Add the completion functions
+	fromAndBudFlagsCompletions := buildahCLI.GetFromAndBudFlagsCompletions()
+	completion.CompleteCommandFlags(cmd, fromAndBudFlagsCompletions)
 	_ = flags.MarkHidden("signature-policy")
 }