Support specific buildpacks for buildpack artifact

docs/content/en/schemas/v2alpha3.json

@@ -494,6 +494,15 @@
           "description": "builder image used.",
           "x-intellij-html-description": "builder image used."
         },
+        "buildpacks": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array",
+          "description": "a list of strings, where each string is a specific buildpack to use with the builder. If you specify buildpacks the builder image automatic detection will be ignored. These buildpacks will be used to build the Image from your source code. Order matters.",
+          "x-intellij-html-description": "a list of strings, where each string is a specific buildpack to use with the builder. If you specify buildpacks the builder image automatic detection will be ignored. These buildpacks will be used to build the Image from your source code. Order matters.",
+          "default": "[]"
+        },
         "dependencies": {
           "$ref": "#/definitions/BuildpackDependencies",
           "description": "file dependencies that skaffold should watch for both rebuilding and file syncing for this artifact.",
@@ -521,6 +530,7 @@
         "builder",
         "runImage",
         "env",
+        "buildpacks",
         "dependencies"
       ],
       "additionalProperties": false,

pkg/skaffold/build/buildpacks/build_test.go

@@ -66,6 +66,25 @@ func TestBuild(t *testing.T) {
 				Image:    "img:latest",
 			},
 		},
+		{
+			description: "success with buildpacks",
+			artifact: &latest.BuildpackArtifact{
+				Builder:      "my/otherBuilder",
+				RunImage:     "my/otherRun",
+				Buildpacks:   []string{"my/buildpack", "my/otherBuildpack"},
+				Dependencies: defaultBuildpackDependencies(),
+			},
+			tag: "img:tag",
+			api: &testutil.FakeAPIClient{},
+			expectedOptions: &pack.BuildOptions{
+				AppPath:    ".",
+				Builder:    "my/otherBuilder",
+				RunImage:   "my/otherRun",
+				Buildpacks: []string{"my/buildpack", "my/otherBuildpack"},
+				Env:        map[string]string{},
+				Image:      "img:latest",
+			},
+		},
 		{
 			description: "invalid ref",
 			artifact: &latest.BuildpackArtifact{

pkg/skaffold/build/buildpacks/lifecycle.go

@@ -62,12 +62,13 @@ func (b *Builder) build(ctx context.Context, out io.Writer, a *latest.Artifact,
 	alreadyPulled := images.AreAlreadyPulled(artifact.Builder, artifact.RunImage)
 
 	if err := runPackBuildFunc(ctx, out, pack.BuildOptions{
-		AppPath:  workspace,
-		Builder:  artifact.Builder,
-		RunImage: artifact.RunImage,
-		Env:      envMap(env),
-		Image:    latest,
-		NoPull:   alreadyPulled,
+		AppPath:    workspace,
+		Builder:    artifact.Builder,
+		RunImage:   artifact.RunImage,
+		Buildpacks: artifact.Buildpacks,
+		Env:        envMap(env),
+		Image:      latest,
+		NoPull:     alreadyPulled,
 	}); err != nil {
 		return "", err
 	}

pkg/skaffold/schema/latest/config.go

@@ -697,6 +697,11 @@ type BuildpackArtifact struct {
 	// For example: `["key1=value1", "key2=value2", "key3={{.ENV_VARIABLE}}"]`.
 	Env []string `yaml:"env,omitempty"`
 
+	// Buildpacks is a list of strings, where each string is a specific buildpack to use with the builder.
+	// If you specify buildpacks the builder image automatic detection will be ignored. These buildpacks will be used to build the Image from your source code.
+	// Order matters.
+	Buildpacks []string `yaml:"buildpacks,omitempty"`
+
 	// Dependencies are the file dependencies that skaffold should watch for both rebuilding and file syncing for this artifact.
 	Dependencies *BuildpackDependencies `yaml:"dependencies,omitempty"`
 }