Apply template args to step image

pkg/builder/common.go

@@ -61,6 +61,7 @@ func ApplyTemplate(u *v1alpha1.Build, tmpl *v1alpha1.BuildTemplate) (*v1alpha1.B
 	steps := build.Spec.Steps
 	for i := range steps {
 		steps[i].Name = applyReplacements(steps[i].Name)
+		steps[i].Image = applyReplacements(steps[i].Image)
 		for ia, a := range steps[i].Args {
 			steps[i].Args[ia] = applyReplacements(a)
 		}

pkg/builder/common_test.go

@@ -98,8 +98,9 @@ func TestApplyTemplate(t *testing.T) {
 		tmpl: &v1alpha1.BuildTemplate{
 			Spec: v1alpha1.BuildTemplateSpec{
 				Steps: []corev1.Container{{
-					Name: "hello ${FOO}",
-					Args: []string{"hello", "to the ${FOO}"},
+					Name:  "hello ${FOO}",
+					Image: "busybox:${FOO}",
+					Args:  []string{"hello", "to the ${FOO}"},
 					Env: []corev1.EnvVar{{
 						Name:  "FOO",
 						Value: "is ${FOO}",
@@ -120,8 +121,9 @@ func TestApplyTemplate(t *testing.T) {
 		want: &v1alpha1.Build{
 			Spec: v1alpha1.BuildSpec{
 				Steps: []corev1.Container{{
-					Name: "hello world",
-					Args: []string{"hello", "to the world"},
+					Name:  "hello world",
+					Image: "busybox:world",
+					Args:  []string{"hello", "to the world"},
 					Env: []corev1.EnvVar{{
 						Name:  "FOO",
 						Value: "is world",
@@ -245,8 +247,9 @@ func TestApplyTemplate(t *testing.T) {
 		tmpl: &v1alpha1.BuildTemplate{
 			Spec: v1alpha1.BuildTemplateSpec{
 				Steps: []corev1.Container{{
-					Name: "hello ${FOO}",
-					Args: []string{"hello", "to the ${FOO}"},
+					Name:  "hello ${FOO}",
+					Image: "busybox:${FOO}",
+					Args:  []string{"hello", "to the ${FOO}"},
 					Env: []corev1.EnvVar{{
 						Name:  "FOO",
 						Value: "is ${FOO}",
@@ -263,8 +266,9 @@ func TestApplyTemplate(t *testing.T) {
 		want: &v1alpha1.Build{
 			Spec: v1alpha1.BuildSpec{
 				Steps: []corev1.Container{{
-					Name: "hello world",
-					Args: []string{"hello", "to the world"},
+					Name:  "hello world",
+					Image: "busybox:world",
+					Args:  []string{"hello", "to the world"},
 					Env: []corev1.EnvVar{{
 						Name:  "FOO",
 						Value: "is world",

test/template-args/0-template.yaml

@@ -18,27 +18,29 @@ metadata:
 spec:
   steps:
   # Use the build's declared argument value.
-  - image: ubuntu
+  - image: ${IMAGE}
     command: ['bash']
     args: ['-c', '[[ ${FOO} == "foo" ]]']
   # Use the template parameter's default value.
-  - image: ubuntu
+  - image: ${IMAGE}
     command: ['bash']
     args: ['-c', '[[ ${BAR} == "bar" ]]']
   # Use the build's declared argument value, overriding the parameter's default
   # value.
-  - image: ubuntu
+  - image: ${IMAGE}
     command: ['bash']
     args: ['-c', '[[ ${BAZ} == "bazzzzz" ]]']
   # This is just an environment variable, not a template parameter.
-  - image: ubuntu
+  - image: ${IMAGE}
     command: ['bash']
     args: ['-c', '[[ $FOO == "foo" ]]']
     env:
     - name: FOO
       value: foo
 
   parameters:
+  - name: IMAGE
+    default: ubuntu
   - name: FOO
   - name: BAR
     default: bar