podman generate spec

implement a new command `podman generate spec` which can formulate a json specgen to be consumed by both the pod
and container creation API.

supported flags are

--verbose (default true) print output to the terminal
--compact print the json output in a single line format to be piped to the API
--filename put the output in a file
--clone rename the pod/ctr in the spec so it won't conflict w/ an existing entity

Signed-off-by: Charlie Doern <cdoern@redhat.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/cmd/podman/generate/spec.go b/cmd/podman/generate/spec.go
new file mode 100644
index 000000000..1cf967424
--- /dev/null
+++ b/cmd/podman/generate/spec.go
@@ -0,0 +1,71 @@
+package pods
+
+import (
+	"fmt"
+	"io/ioutil"
+
+	"github.com/containers/common/pkg/completion"
+	"github.com/containers/podman/v4/cmd/podman/common"
+	"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 (
+	specCmd = &cobra.Command{
+		Use:               "spec [options] {CONTAINER|POD}",
+		Short:             "Generate Specgen JSON based on containers or pods",
+		Long:              "Generate Specgen JSON based on containers or pods",
+		RunE:              spec,
+		Args:              cobra.ExactArgs(1),
+		ValidArgsFunction: common.AutocompleteContainersAndPods,
+		Example:           `podman generate spec ctrID`,
+	}
+)
+
+var (
+	opts *entities.GenerateSpecOptions
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: specCmd,
+		Parent:  generateCmd,
+	})
+	opts = &entities.GenerateSpecOptions{}
+	flags := specCmd.Flags()
+
+	filenameFlagName := "filename"
+	flags.StringVarP(&opts.FileName, filenameFlagName, "f", "", "Write output to the specified path")
+	_ = specCmd.RegisterFlagCompletionFunc(filenameFlagName, completion.AutocompleteNone)
+
+	compactFlagName := "compact"
+	flags.BoolVarP(&opts.Compact, compactFlagName, "c", false, "Print the json in a compact format for consumption")
+
+	nameFlagName := "name"
+	flags.BoolVarP(&opts.Name, nameFlagName, "n", true, "Specify a new name for the generated spec")
+
+	flags.SetNormalizeFunc(utils.AliasFlags)
+}
+
+func spec(cmd *cobra.Command, args []string) error {
+	opts.ID = args[0]
+	report, err := registry.ContainerEngine().GenerateSpec(registry.GetContext(), opts)
+	if err != nil {
+		return err
+	}
+
+	// if we are looking to print the output, do not mess it up by printing the path
+	// if we are using -v the user probably expects to pipe the output somewhere else
+	if len(opts.FileName) > 0 {
+		err = ioutil.WriteFile(opts.FileName, report.Data, 0644)
+		if err != nil {
+			return err
+		}
+		fmt.Println(opts.FileName)
+	} else {
+		fmt.Println(string(report.Data))
+	}
+	return nil
+}