feat: Support Bazel platform mappings

docs-v2/content/en/schemas/v4beta10.json

@@ -694,6 +694,14 @@
             "[\"-flag\", \"--otherflag\"]"
           ]
         },
+        "platforms": {
+          "items": {
+            "$ref": "#/definitions/BazelPlatformMapping"
+          },
+          "type": "array",
+          "description": "configure the --platforms flag for `bazel build` based on the configured skaffold target platform.",
+          "x-intellij-html-description": "configure the --platforms flag for <code>bazel build</code> based on the configured skaffold target platform."
+        },
         "target": {
           "type": "string",
           "description": "`bazel build` target to run.",
@@ -705,13 +713,40 @@
       },
       "preferredOrder": [
         "target",
-        "args"
+        "args",
+        "platforms"
       ],
       "additionalProperties": false,
       "type": "object",
       "description": "describes an artifact built with [Bazel](https://bazel.build/).",
       "x-intellij-html-description": "describes an artifact built with <a href=\"https://bazel.build/\">Bazel</a>."
     },
+    "BazelPlatformMapping": {
+      "required": [
+        "platform",
+        "target"
+      ],
+      "properties": {
+        "platform": {
+          "type": "string",
+          "description": "skaffold platform.",
+          "x-intellij-html-description": "skaffold platform."
+        },
+        "target": {
+          "type": "string",
+          "description": "bazel platform target to be passed to bazel's `--platforms` flag.",
+          "x-intellij-html-description": "bazel platform target to be passed to bazel's <code>--platforms</code> flag."
+        }
+      },
+      "preferredOrder": [
+        "platform",
+        "target"
+      ],
+      "additionalProperties": false,
+      "type": "object",
+      "description": "relates a skaffold platform (like 'linux/amd64') to a workspace-specific bazel platform target (e.g. '//platforms:linux_amd64').",
+      "x-intellij-html-description": "relates a skaffold platform (like 'linux/amd64') to a workspace-specific bazel platform target (e.g. '//platforms:linux_amd64')."
+    },
     "BuildConfig": {
       "type": "object",
       "anyOf": [

examples/bazel/BUILD.bazel

@@ -1,4 +1,3 @@
-load("@aspect_bazel_lib//lib:transitions.bzl", "platform_transition_filegroup")
 load("@rules_go//go:def.bzl", "go_binary", "go_library")
 load("@rules_oci//oci:defs.bzl", "oci_image", "oci_tarball")
 load("@rules_pkg//:pkg.bzl", "pkg_tar")
@@ -31,18 +30,8 @@ oci_image(
     tars = [":app_layer"],
 )
 
-# This is the target that should be released to the target platform
-platform_transition_filegroup(
-    name = "transitioned_image",
-    srcs = [":image"],
-    target_platform = select({
-        "@platforms//cpu:arm64": "@rules_go//go/toolchain:linux_arm64",
-        "@platforms//cpu:x86_64": "@rules_go//go/toolchain:linux_amd64",
-    }),
-)
-
-# $ bazel build :tarball
-# $ docker load --input $(bazel cquery --output=files :tarball)
+# $ bazel build :skaffold-example.tar
+# $ docker load --input $(bazel cquery --output=files :skaffold-example.tar)
 # $ docker run --rm gcr.io/example:latest
 
 oci_tarball(

examples/bazel/MODULE.bazel

@@ -1,4 +1,3 @@
-bazel_dep(name = "aspect_bazel_lib", version = "1.31.1")
 bazel_dep(name = "gazelle", version = "0.31.0")
 bazel_dep(name = "platforms", version = "0.0.5")
 bazel_dep(name = "rules_oci", version = "1.2.0")

examples/bazel/README.md

@@ -12,7 +12,7 @@ build:
   - image: skaffold-bazel
     context: .
     bazel:
-      target: //:skaffold_example.tar
+      target: //:skaffold-example.tar
 ```
 
 1. make sure the `context` contains the bazel files (`WORKSPACE`, `BUILD`)

integration/examples/bazel/BUILD.bazel

@@ -1,4 +1,3 @@
-load("@aspect_bazel_lib//lib:transitions.bzl", "platform_transition_filegroup")
 load("@rules_go//go:def.bzl", "go_binary", "go_library")
 load("@rules_oci//oci:defs.bzl", "oci_image", "oci_tarball")
 load("@rules_pkg//:pkg.bzl", "pkg_tar")
@@ -31,18 +30,8 @@ oci_image(
     tars = [":app_layer"],
 )
 
-# This is the target that should be released to the target platform
-platform_transition_filegroup(
-    name = "transitioned_image",
-    srcs = [":image"],
-    target_platform = select({
-        "@platforms//cpu:arm64": "@rules_go//go/toolchain:linux_arm64",
-        "@platforms//cpu:x86_64": "@rules_go//go/toolchain:linux_amd64",
-    }),
-)
-
-# $ bazel build :tarball
-# $ docker load --input $(bazel cquery --output=files :tarball)
+# $ bazel build :skaffold-example.tar
+# $ docker load --input $(bazel cquery --output=files :skaffold-example.tar)
 # $ docker run --rm gcr.io/example:latest
 
 oci_tarball(

integration/examples/bazel/MODULE.bazel

@@ -1,4 +1,3 @@
-bazel_dep(name = "aspect_bazel_lib", version = "1.31.1")
 bazel_dep(name = "gazelle", version = "0.31.0")
 bazel_dep(name = "platforms", version = "0.0.5")
 bazel_dep(name = "rules_oci", version = "1.2.0")

integration/examples/bazel/README.md

@@ -12,7 +12,7 @@ build:
   - image: skaffold-bazel
     context: .
     bazel:
-      target: //:skaffold_example.tar
+      target: //:skaffold-example.tar
 ```
 
 1. make sure the `context` contains the bazel files (`WORKSPACE`, `BUILD`)

integration/examples/bazel/skaffold.yaml

@@ -9,6 +9,11 @@ build:
     - image: skaffold-bazel
       bazel:
         target: //:skaffold-example.tar
+        platforms:
+          - platform: linux/amd64
+            target: "@rules_go//go/toolchain:linux_amd64"
+          - platform: linux/arm64
+            target: "@rules_go//go/toolchain:linux_arm64"
 deploy:
   kubectl: {}
 manifests:

pkg/skaffold/build/bazel/build.go

@@ -45,7 +45,7 @@ func (b *Builder) Build(ctx context.Context, out io.Writer, artifact *latest.Art
 
 	a := artifact.ArtifactType.BazelArtifact
 
-	tarPath, err := b.buildTar(ctx, out, artifact.Workspace, a)
+	tarPath, err := b.buildTar(ctx, out, artifact.Workspace, a, matcher)
 	if err != nil {
 		return "", err
 	}
@@ -58,7 +58,7 @@ func (b *Builder) Build(ctx context.Context, out io.Writer, artifact *latest.Art
 
 func (b *Builder) SupportedPlatforms() platform.Matcher { return platform.All }
 
-func (b *Builder) buildTar(ctx context.Context, out io.Writer, workspace string, a *latest.BazelArtifact) (string, error) {
+func (b *Builder) buildTar(ctx context.Context, out io.Writer, workspace string, a *latest.BazelArtifact, matcher platform.Matcher) (string, error) {
 	if !strings.HasSuffix(a.BuildTarget, ".tar") {
 		return "", errors.New("the bazel build target should end with .tar, see https://github.com/bazelbuild/rules_docker#using-with-docker-locally")
 	}
@@ -67,6 +67,16 @@ func (b *Builder) buildTar(ctx context.Context, out io.Writer, workspace string,
 	args = append(args, a.BuildArgs...)
 	args = append(args, a.BuildTarget)
 
+	platformMappings := a.PlatformMappings
+	for _, mapping := range platformMappings {
+		m, err := platform.Parse([]string{mapping.Platform})
+		if err == nil {
+			if matcher.Intersect(m).IsNotEmpty() {
+				args = append(args, fmt.Sprintf("--platforms=%s", mapping.BazelPlatformTarget))
+			}
+		}
+	}
+
 	if output.IsColorable(out) {
 		args = append(args, "--color=yes")
 	} else {

pkg/skaffold/build/bazel/build_test.go

@@ -23,6 +23,8 @@ import (
 	"path/filepath"
 	"testing"
 
+	specs "github.com/opencontainers/image-spec/specs-go/v1"
+
 	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/docker"
 	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/platform"
 	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/schema/latest"
@@ -77,6 +79,37 @@ func TestBazelTarPathPrependExecutionRoot(t *testing.T) {
 	})
 }
 
+func TestBazelAddPlatforms(t *testing.T) {
+	testutil.Run(t, "", func(t *testutil.T) {
+		t.Override(&util.DefaultExecCommand, testutil.CmdRun("bazel build //:app.tar --platforms=//platforms:linux-x86_64 --color=no").AndRunOut(
+			"bazel cquery //:app.tar --output starlark --starlark:expr target.files.to_list()[0].path",
+			"app.tar").AndRunOut("bazel info execution_root", ".."))
+		testutil.CreateFakeImageTar("bazel:app", "../app.tar")
+
+		artifact := &latest.Artifact{
+			Workspace: "..",
+			ArtifactType: latest.ArtifactType{
+				BazelArtifact: &latest.BazelArtifact{
+					BuildTarget: "//:app.tar",
+					PlatformMappings: []latest.BazelPlatformMapping{
+						{
+							Platform:            "linux/amd64",
+							BazelPlatformTarget: "//platforms:linux-x86_64",
+						},
+					},
+				},
+			},
+		}
+
+		testPlatform := platform.Matcher{Platforms: []specs.Platform{{Architecture: "amd64", OS: "linux"}}}
+
+		builder := NewArtifactBuilder(fakeLocalDaemon(), &mockConfig{}, false)
+		_, err := builder.Build(context.Background(), io.Discard, artifact, "img:tag", testPlatform)
+
+		t.CheckNoError(err)
+	})
+}
+
 func TestBuildBazelFailInvalidTarget(t *testing.T) {
 	testutil.Run(t, "", func(t *testutil.T) {
 		artifact := &latest.Artifact{

pkg/skaffold/schema/latest/config.go

@@ -331,6 +331,16 @@ type TaggerComponent struct {
 	Component TagPolicy `yaml:",inline" yamltags:"skipTrim"`
 }
 
+// BazelPlatformMapping relates a skaffold platform (like 'linux/amd64')
+// to a workspace-specific bazel platform target (e.g. '//platforms:linux_amd64').
+type BazelPlatformMapping struct {
+	// Platform is the skaffold platform.
+	Platform string `yaml:"platform" yamltags:"required"`
+
+	// BazelPlatformTarget is the bazel platform target to be passed to bazel's `--platforms` flag.
+	BazelPlatformTarget string `yaml:"target" yamltags:"required"`
+}
+
 // BuildType contains the specific implementation and parameters needed
 // for the build step. Only one field should be populated.
 type BuildType struct {
@@ -1597,6 +1607,10 @@ type BazelArtifact struct {
 	// BuildArgs are additional args to pass to `bazel build`.
 	// For example: `["-flag", "--otherflag"]`.
 	BuildArgs []string `yaml:"args,omitempty"`
+
+	// PlatformMappings configure the --platforms flag for `bazel build`
+	// based on the configured skaffold target platform.
+	PlatformMappings []BazelPlatformMapping `yaml:"platforms,omitempty"`
 }
 
 // KoArtifact builds images using [ko](https://github.com/google/ko).