Initial implementation of renaming containers

Basic theory: We remove the container, but *only from the DB*.
We leave it in c/storage, we leave the lock allocated, we leave
it running (if it is). Then we create an identical container with
an altered name, and add that back to the database. Theoretically
we now have a renamed container.

The advantage of this approach is that it doesn't just apply to
rename - we can use this to make *any* configuration change to a
container that does not alter its container ID.

Potential problems are numerous. This process is *THOROUGHLY*
non-atomic at present - if you `kill -9` Podman mid-rename things
will be in a bad place, for example. Also, we can't rename
containers that can't be removed normally - IE, containers with
dependencies (pod infra containers, for example).

The largest potential improvement will be to move the majority of
the work into the DB, with a `RecreateContainer()` method - that
will add atomicity, and let us remove the container without
worrying about depencies and similar issues.

Potential problems: long-running processes that edit the DB and
may have an older version of the configuration around. Most
notable example is `podman run --rm` - the removal command needed
to be manually edited to avoid this one. This begins to get at
the heart of me not wanting to do this in the first place...

This provides CLI and API implementations for frontend, but no
tunnel implementation. It will be added in a future release (just
held back for time now - we need this in 3.0 and are running low
on time).

This is honestly kind of horrifying, but I think it will work.

Signed-off-by: Matthew Heon <mheon@redhat.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/cmd/podman/containers/rename.go b/cmd/podman/containers/rename.go
new file mode 100644
index 000000000..9c94e6272
--- /dev/null
+++ b/cmd/podman/containers/rename.go
@@ -0,0 +1,56 @@
+package containers
+
+import (
+	"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/pkg/errors"
+	"github.com/spf13/cobra"
+)
+
+var (
+	renameDescription = "The podman rename command allows you to rename an existing container"
+	renameCommand     = &cobra.Command{
+		Use:               "rename CONTAINER NAME",
+		Short:             "Rename an existing container",
+		Long:              renameDescription,
+		RunE:              rename,
+		Args:              cobra.ExactArgs(2),
+		ValidArgsFunction: common.AutocompletePortCommand,
+		Example:           "podman rename containerA newName",
+	}
+
+	containerRenameCommand = &cobra.Command{
+		Use:               renameCommand.Use,
+		Short:             renameCommand.Short,
+		Long:              renameCommand.Long,
+		RunE:              renameCommand.RunE,
+		Args:              renameCommand.Args,
+		ValidArgsFunction: renameCommand.ValidArgsFunction,
+		Example:           "podman container rename containerA newName",
+	}
+)
+
+func init() {
+	// TODO: Once bindings are done, add this to TunnelMode
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode},
+		Command: renameCommand,
+	})
+
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode},
+		Command: containerRenameCommand,
+		Parent:  containerCmd,
+	})
+}
+
+func rename(cmd *cobra.Command, args []string) error {
+	if len(args) > 2 {
+		return errors.Errorf("must provide at least two arguments to rename")
+	}
+	renameOpts := entities.ContainerRenameOptions{
+		NewName: args[1],
+	}
+	return registry.ContainerEngine().ContainerRename(registry.GetContext(), args[0], renameOpts)
+}