Add "podman kube generate" command

"podman kube generate" creates Kubernetes YAML from Podman containers,
pods or volumes. Users will still be able to use "podman generate
kube" as an alias of "kube generate".

Signed-off-by: Niall Crowe <nicrowe@redhat.com>

1 files changed, 109 insertions, 0 deletions

diff --git a/cmd/podman/kube/generate.go b/cmd/podman/kube/generate.go
new file mode 100644
index 000000000..6df4b55fc
--- /dev/null
+++ b/cmd/podman/kube/generate.go
@@ -0,0 +1,109 @@
+package kube
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+
+	"github.com/containers/common/pkg/completion"
+	"github.com/containers/podman/v4/cmd/podman/common"
+	"github.com/containers/podman/v4/cmd/podman/generate"
+	"github.com/containers/podman/v4/cmd/podman/registry"
+	"github.com/containers/podman/v4/cmd/podman/utils"
+	"github.com/containers/podman/v4/pkg/domain/entities"
+	"github.com/spf13/cobra"
+)
+
+var (
+	generateOptions     = entities.GenerateKubeOptions{}
+	generateFile        = ""
+	generateDescription = `Command generates Kubernetes Pod, Service or PersistenVolumeClaim YAML (v1 specification) from Podman containers, pods or volumes.
+
+  Whether the input is for a container or pod, Podman will always generate the specification as a pod.`
+
+	generateKubeCmd = &cobra.Command{
+		Use:               "generate [options] {CONTAINER...|POD...|VOLUME...}",
+		Short:             "Generate Kubernetes YAML from containers, pods or volumes.",
+		Long:              generateDescription,
+		RunE:              generateKube,
+		Args:              cobra.MinimumNArgs(1),
+		ValidArgsFunction: common.AutocompleteForGenerate,
+		Example: `podman kube generate ctrID
+  podman kube generate podID
+  podman kube generate --service podID
+  podman kube generate volumeName
+  podman kube generate ctrID podID volumeName --service`,
+	}
+	kubeGenerateDescription = generateDescription
+
+	kubeGenerateCmd = &cobra.Command{
+		Use:               "kube [options] {CONTAINER...|POD...|VOLUME...}",
+		Short:             "Generate Kubernetes YAML from containers, pods or volumes.",
+		Long:              kubeGenerateDescription,
+		RunE:              kubeGenerate,
+		Args:              cobra.MinimumNArgs(1),
+		ValidArgsFunction: common.AutocompleteForGenerate,
+		Example: `podman kube generate ctrID
+  podman kube generate podID
+  podman kube generate --service podID
+  podman kube generate volumeName
+  podman kube generate ctrID podID volumeName --service`,
+	}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: generateKubeCmd,
+		Parent:  kubeCmd,
+	})
+	generateFlags(generateKubeCmd)
+
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: kubeGenerateCmd,
+		Parent:  generate.GenerateCmd,
+	})
+	generateFlags(kubeGenerateCmd)
+}
+
+func generateFlags(cmd *cobra.Command) {
+	flags := cmd.Flags()
+	flags.BoolVarP(&generateOptions.Service, "service", "s", false, "Generate YAML for a Kubernetes service object")
+
+	filenameFlagName := "filename"
+	flags.StringVarP(&generateFile, filenameFlagName, "f", "", "Write output to the specified path")
+	_ = cmd.RegisterFlagCompletionFunc(filenameFlagName, completion.AutocompleteDefault)
+
+	flags.SetNormalizeFunc(utils.AliasFlags)
+}
+
+func generateKube(cmd *cobra.Command, args []string) error {
+	report, err := registry.ContainerEngine().GenerateKube(registry.GetContext(), args, generateOptions)
+	if err != nil {
+		return err
+	}
+	content, err := ioutil.ReadAll(report.Reader)
+	if err != nil {
+		return err
+	}
+	if r, ok := report.Reader.(io.ReadCloser); ok {
+		defer r.Close()
+	}
+
+	if cmd.Flags().Changed("filename") {
+		if _, err := os.Stat(generateFile); err == nil {
+			return fmt.Errorf("cannot write to %q; file exists", generateFile)
+		}
+		if err := ioutil.WriteFile(generateFile, content, 0644); err != nil {
+			return fmt.Errorf("cannot write to %q: %w", generateFile, err)
+		}
+		return nil
+	}
+
+	fmt.Println(string(content))
+	return nil
+}
+
+func kubeGenerate(cmd *cobra.Command, args []string) error {
+	return generateKube(cmd, args)
+}