pod create --replace

Add a `--replace` flag to the `pod create` command.  If another pod with
the same name already exists, it will be replaced and removed.

Adding this flag is motivated by #5485 to make running Podman in systemd
units (or any other scripts/automation) more robust.  In case of a
crash, a pod may not be removed by a sytemd unit anymore.  The
`--replace` flag allows for supporting crashes.

Note that the `--replace` flag does not require the `--name` flag to be
set, so it can be set unconditionally in `podman generate systemd`.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

2 files changed, 31 insertions, 6 deletions

diff --git a/cmd/podman/pods/create.go b/cmd/podman/pods/create.go
index 51b7a7d52..835a62359 100644
--- a/cmd/podman/pods/create.go
+++ b/cmd/podman/pods/create.go
@@ -39,6 +39,7 @@ var (
 	createOptions     entities.PodCreateOptions
 	labels, labelFile []string
 	podIDFile         string
+	replace           bool
 	share             string
 )
 
@@ -61,6 +62,7 @@ func init() {
 	flags.StringVarP(&createOptions.Name, "name", "n", "", "Assign a name to the pod")
 	flags.StringVarP(&createOptions.Hostname, "hostname", "", "", "Set a hostname to the pod")
 	flags.StringVar(&podIDFile, "pod-id-file", "", "Write the pod ID to the file")
+	flags.BoolVar(&replace, "replace", false, "If a pod with the same exists, replace it")
 	flags.StringVar(&share, "share", specgen.DefaultKernelNamespaces, "A comma delimited list of kernel namespaces the pod will share")
 	flags.SetNormalizeFunc(aliasNetworkFlag)
 }
@@ -147,6 +149,12 @@ func create(cmd *cobra.Command, args []string) error {
 		}
 	}
 
+	if replace {
+		if err := replacePod(createOptions.Name); err != nil {
+			return err
+		}
+	}
+
 	response, err := registry.ContainerEngine().PodCreate(context.Background(), createOptions)
 	if err != nil {
 		return err
@@ -159,3 +167,14 @@ func create(cmd *cobra.Command, args []string) error {
 	fmt.Println(response.Id)
 	return nil
 }
+
+func replacePod(name string) error {
+	if len(name) == 0 {
+		return errors.New("cannot replace pod without --name being set")
+	}
+	rmOptions := entities.PodRmOptions{
+		Force:  true, // stop and remove pod
+		Ignore: true, // ignore if pod doesn't exist
+	}
+	return removePods([]string{name}, rmOptions, false)
+}
diff --git a/cmd/podman/pods/rm.go b/cmd/podman/pods/rm.go
index 8de0bce9e..ec8dae1d1 100644
--- a/cmd/podman/pods/rm.go
+++ b/cmd/podman/pods/rm.go
@@ -58,24 +58,30 @@ func init() {
 }
 
 func rm(cmd *cobra.Command, args []string) error {
-	var (
-		errs utils.OutputErrors
-	)
-
 	ids, err := common.ReadPodIDFiles(rmOptions.PodIDFiles)
 	if err != nil {
 		return err
 	}
 	args = append(args, ids...)
+	return removePods(args, rmOptions.PodRmOptions, true)
+}
 
-	responses, err := registry.ContainerEngine().PodRm(context.Background(), args, rmOptions.PodRmOptions)
+// removePods removes the specified pods (names or IDs).  Allows for sharing
+// pod-removal logic across commands.
+func removePods(namesOrIDs []string, rmOptions entities.PodRmOptions, printIDs bool) error {
+	var errs utils.OutputErrors
+
+	responses, err := registry.ContainerEngine().PodRm(context.Background(), namesOrIDs, rmOptions)
 	if err != nil {
 		return err
 	}
+
 	// in the cli, first we print out all the successful attempts
 	for _, r := range responses {
 		if r.Err == nil {
-			fmt.Println(r.Id)
+			if printIDs {
+				fmt.Println(r.Id)
+			}
 		} else {
 			errs = append(errs, r.Err)
 		}