Add WithImageConfigArgs to replace CMD on image

crosbymichael · crosbymichael · commit e956441fe0f5 · 2018-07-27T12:09:11.000-04:00
This allows users to provide args for the process arguments while
creating the base spec with an image.  It provides the same symantics as
Docker where additional args replace the CMD while leaving the
ENTRYPOINT the same.

Signed-off-by: Michael Crosby &lt;crosbymichael@gmail.com&gt;
diff --git a/oci/spec_opts_unix.go b/oci/spec_opts_unix.go
@@ -106,6 +106,12 @@ func WithLinuxNamespace(ns specs.LinuxNamespace) SpecOpts {
 
 // WithImageConfig configures the spec to from the configuration of an Image
 func WithImageConfig(image Image) SpecOpts {
+	return WithImageConfigArgs(image, nil)
+}
+
+// WithImageConfigArgs configures the spec to from the configuration of an Image with additional args that
+// replaces the CMD of the image
+func WithImageConfigArgs(image Image, args []string) SpecOpts {
 	return func(ctx context.Context, client Client, c *containers.Container, s *Spec) error {
 		ic, err := image.Config(ctx)
 		if err != nil {
@@ -133,6 +139,9 @@ func WithImageConfig(image Image) SpecOpts {
 		setProcess(s)
 		s.Process.Env = append(s.Process.Env, config.Env...)
 		cmd := config.Cmd
+		if len(args) > 0 {
+			cmd = args
+		}
 		s.Process.Args = append(config.Entrypoint, cmd...)
 		cwd := config.WorkingDir
 		if cwd == "" {
