play kube: fix args/command handling

pkg/specgen/generate/kube/kube.go

@@ -112,11 +112,18 @@ func ToSpecGen(ctx context.Context, containerYAML v1.Container, iid string, newI
 		return nil, err
 	}
 	s.WorkDir = "/"
+	// We will use "Docker field name" internally here to avoid confusion
+	// and reference the "Kubernetes field name" when referencing the YAML
+	// ref: https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#notes
+	entrypoint := []string{}
+	cmd := []string{}
 	if imageData != nil && imageData.Config != nil {
 		if imageData.Config.WorkingDir != "" {
 			s.WorkDir = imageData.Config.WorkingDir
 		}
-		s.Command = imageData.Config.Entrypoint
+		// Pull entrypoint and cmd from image
+		entrypoint = imageData.Config.Entrypoint
+		cmd = imageData.Config.Cmd
 		s.Labels = imageData.Config.Labels
 		if len(imageData.Config.StopSignal) > 0 {
 			stopSignal, err := util.ParseSignal(imageData.Config.StopSignal)
@@ -126,13 +133,18 @@ func ToSpecGen(ctx context.Context, containerYAML v1.Container, iid string, newI
 			s.StopSignal = &stopSignal
 		}
 	}
+	// If only the yaml.Command is specified, set it as the entrypoint and drop the image Cmd
 	if len(containerYAML.Command) != 0 {
-		s.Command = containerYAML.Command
+		entrypoint = containerYAML.Command
+		cmd = []string{}
 	}
-	// doc https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#notes
+	// Only override the cmd field if yaml.Args is specified
+	// Keep the image entrypoint, or the yaml.command if specified
 	if len(containerYAML.Args) != 0 {
-		s.Command = append(s.Command, containerYAML.Args...)
+		cmd = containerYAML.Args
 	}
+
+	s.Command = append(entrypoint, cmd...)
 	// FIXME,
 	// we are currently ignoring imageData.Config.ExposedPorts
 	if containerYAML.WorkingDir != "" {

test/e2e/play_kube_test.go

@@ -820,8 +820,28 @@ var _ = Describe("Podman play kube", func() {
 		Expect(inspect.OutputToString()).To(ContainSubstring(correctCmd))
 	})
 
+	// If you do not supply command or args for a Container, the defaults defined in the Docker image are used.
+	It("podman play kube test correct args and cmd when not specified", func() {
+		pod := getPod(withCtr(getCtr(withImage(registry), withCmd(nil), withArg(nil))))
+		err := generateKubeYaml("pod", pod, kubeYaml)
+		Expect(err).To(BeNil())
+
+		kube := podmanTest.Podman([]string{"play", "kube", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube.ExitCode()).To(Equal(0))
+
+		inspect := podmanTest.Podman([]string{"inspect", getCtrNameInPod(pod), "--format", "'{{ .Config.Cmd }}'"})
+		inspect.WaitWithDefaultTimeout()
+		Expect(inspect.ExitCode()).To(Equal(0))
+
+		// this image's ENTRYPOINT is `/entrypoint.sh` and it's COMMAND is `/etc/docker/registry/config.yml`
+		Expect(inspect.OutputToString()).To(ContainSubstring(`[/entrypoint.sh /etc/docker/registry/config.yml]`))
+	})
+
+	// If you supply a command but no args for a Container, only the supplied command is used.
+	// The default EntryPoint and the default Cmd defined in the Docker image are ignored.
 	It("podman play kube test correct command with only set command in yaml file", func() {
-		pod := getPod(withCtr(getCtr(withCmd([]string{"echo", "hello"}), withArg(nil))))
+		pod := getPod(withCtr(getCtr(withImage(registry), withCmd([]string{"echo", "hello"}), withArg(nil))))
 		err := generateKubeYaml("pod", pod, kubeYaml)
 		Expect(err).To(BeNil())
 
@@ -837,8 +857,9 @@ var _ = Describe("Podman play kube", func() {
 		Expect(inspect.OutputToString()).To(ContainSubstring(`[echo hello]`))
 	})
 
+	// If you supply only args for a Container, the default Entrypoint defined in the Docker image is run with the args that you supplied.
 	It("podman play kube test correct command with only set args in yaml file", func() {
-		pod := getPod(withCtr(getCtr(withImage(redis), withCmd(nil), withArg([]string{"echo", "hello"}))))
+		pod := getPod(withCtr(getCtr(withImage(registry), withCmd(nil), withArg([]string{"echo", "hello"}))))
 		err := generateKubeYaml("pod", pod, kubeYaml)
 		Expect(err).To(BeNil())
 
@@ -849,9 +870,27 @@ var _ = Describe("Podman play kube", func() {
 		inspect := podmanTest.Podman([]string{"inspect", getCtrNameInPod(pod), "--format", "'{{ .Config.Cmd }}'"})
 		inspect.WaitWithDefaultTimeout()
 		Expect(inspect.ExitCode()).To(Equal(0))
-		// this image's ENTRYPOINT is called `docker-entrypoint.sh`
-		// so result should be `docker-entrypoint.sh + withArg(...)`
-		Expect(inspect.OutputToString()).To(ContainSubstring(`[docker-entrypoint.sh echo hello]`))
+		// this image's ENTRYPOINT is `/entrypoint.sh`
+		// so result should be `/entrypoint.sh + withArg(...)`
+		Expect(inspect.OutputToString()).To(ContainSubstring(`[/entrypoint.sh echo hello]`))
+	})
+
+	// If you supply a command and args,
+	// the default Entrypoint and the default Cmd defined in the Docker image are ignored.
+	// Your command is run with your args.
+	It("podman play kube test correct command with both set args and cmd in yaml file", func() {
+		pod := getPod(withCtr(getCtr(withImage(registry), withCmd([]string{"echo"}), withArg([]string{"hello"}))))
+		err := generateKubeYaml("pod", pod, kubeYaml)
+		Expect(err).To(BeNil())
+
+		kube := podmanTest.Podman([]string{"play", "kube", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube.ExitCode()).To(Equal(0))
+
+		inspect := podmanTest.Podman([]string{"inspect", getCtrNameInPod(pod), "--format", "'{{ .Config.Cmd }}'"})
+		inspect.WaitWithDefaultTimeout()
+		Expect(inspect.ExitCode()).To(Equal(0))
+		Expect(inspect.OutputToString()).To(ContainSubstring(`[echo hello]`))
 	})
 
 	It("podman play kube test correct output", func() {