add podman container|image exists

Add an exists subcommand to podman container and podman image that allows
users to verify the existence of a container or image by ID or name.  The return
code can be 0 (success), 1 (failed to find), or 125 (failed to work with runtime).

Issue #1845

Signed-off-by: baude <bbaude@redhat.com>

3 files changed, 85 insertions, 0 deletions

diff --git a/cmd/podman/container.go b/cmd/podman/container.go
index ff634278f..b6262f890 100644
--- a/cmd/podman/container.go
+++ b/cmd/podman/container.go
@@ -9,6 +9,7 @@ var (
 		attachCommand,
 		checkpointCommand,
 		cleanupCommand,
+		containerExistsCommand,
 		commitCommand,
 		createCommand,
 		diffCommand,
diff --git a/cmd/podman/exists.go b/cmd/podman/exists.go
new file mode 100644
index 000000000..2f7b7c185
--- /dev/null
+++ b/cmd/podman/exists.go
@@ -0,0 +1,83 @@
+package main
+
+import (
+	"os"
+
+	"github.com/containers/libpod/cmd/podman/libpodruntime"
+	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/libpod/image"
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+var (
+	imageExistsDescription = `
+	podman image exists
+
+	Check if an image exists in local storage
+`
+
+	imageExistsCommand = cli.Command{
+		Name:         "exists",
+		Usage:        "Check if an image exists in local storage",
+		Description:  imageExistsDescription,
+		Action:       imageExistsCmd,
+		ArgsUsage:    "IMAGE-NAME",
+		OnUsageError: usageErrorHandler,
+	}
+)
+
+var (
+	containerExistsDescription = `
+	podman container exists
+
+	Check if a container exists in local storage
+`
+
+	containerExistsCommand = cli.Command{
+		Name:         "exists",
+		Usage:        "Check if a container exists in local storage",
+		Description:  containerExistsDescription,
+		Action:       containerExistsCmd,
+		ArgsUsage:    "CONTAINER-NAME",
+		OnUsageError: usageErrorHandler,
+	}
+)
+
+func imageExistsCmd(c *cli.Context) error {
+	args := c.Args()
+	if len(args) > 1 || len(args) < 1 {
+		return errors.New("you may only check for the existence of one image at a time")
+	}
+	runtime, err := libpodruntime.GetRuntime(c)
+	if err != nil {
+		return errors.Wrapf(err, "could not get runtime")
+	}
+	defer runtime.Shutdown(false)
+	if _, err := runtime.ImageRuntime().NewFromLocal(args[0]); err != nil {
+		if errors.Cause(err) == image.ErrNoSuchImage {
+			os.Exit(1)
+		}
+		return err
+	}
+	return nil
+}
+
+func containerExistsCmd(c *cli.Context) error {
+	args := c.Args()
+	if len(args) > 1 || len(args) < 1 {
+		return errors.New("you may only check for the existence of one container at a time")
+	}
+	runtime, err := libpodruntime.GetRuntime(c)
+	if err != nil {
+		return errors.Wrapf(err, "could not get runtime")
+	}
+	defer runtime.Shutdown(false)
+	if _, err := runtime.LookupContainer(args[0]); err != nil {
+		if errors.Cause(err) == libpod.ErrNoSuchCtr {
+			os.Exit(1)
+		}
+		return err
+	}
+	return nil
+}
diff --git a/cmd/podman/image.go b/cmd/podman/image.go
index e67f61799..418b442e3 100644
--- a/cmd/podman/image.go
+++ b/cmd/podman/image.go
@@ -9,6 +9,7 @@ var (
 		buildCommand,
 		historyCommand,
 		importCommand,
+		imageExistsCommand,
 		inspectCommand,
 		loadCommand,
 		lsImagesCommand,