feat: support target architectures on subpackages

docs/BUILD-FILE.md

@@ -23,6 +23,8 @@ The following are the high level sections for the build file, with detailed desc
 ### subpackages
 
    List of subpackages that this package also produces. For example, docs.
+   Subpackages may define their own `target-architecture` entries to limit
+   which architectures produce that subpackage.
 
 ### data
 
@@ -499,4 +501,3 @@ TODO(vaikas): melange config points to apko here:
 
 # pipeline
 Pipeline defines the ordered steps to build the package.
-

pkg/build/build.go

@@ -296,6 +296,39 @@ func (b *Build) Close(ctx context.Context) error {
 	return errors.Join(errs...)
 }
 
+func filterSubpackages(ctx context.Context, subpackages []config.Subpackage, arch apko_types.Architecture) []config.Subpackage {
+	log := clog.FromContext(ctx)
+
+	return slices.DeleteFunc(subpackages, func(sp config.Subpackage) bool {
+		result, err := shouldRun(sp.If)
+		if err != nil {
+			// This shouldn't give an error because we evaluate it in Compile.
+			panic(err)
+		}
+		if !result {
+			log.Infof("skipping subpackage %s because %s == false", sp.Name, sp.If)
+			return true
+		}
+
+		if !subpackageTargetsArch(sp, arch) {
+			log.Infof("skipping subpackage %s because target-architecture does not include %s", sp.Name, arch.ToAPK())
+			return true
+		}
+
+		return false
+	})
+}
+
+func subpackageTargetsArch(sp config.Subpackage, arch apko_types.Architecture) bool {
+	if len(sp.TargetArchitecture) == 0 {
+		return true
+	}
+	if len(sp.TargetArchitecture) == 1 && sp.TargetArchitecture[0] == "all" {
+		return true
+	}
+	return slices.Contains(sp.TargetArchitecture, arch.ToAPK())
+}
+
 // buildGuest invokes apko to build the guest environment, returning a reference to the image
 // loaded by the OCI Image loader.
 //
@@ -594,19 +627,7 @@ func (b *Build) BuildPackage(ctx context.Context) error {
 		return fmt.Errorf("compiling %s: %w", b.ConfigFile, err)
 	}
 
-	// Filter out any subpackages with false If conditions.
-	b.Configuration.Subpackages = slices.DeleteFunc(b.Configuration.Subpackages, func(sp config.Subpackage) bool {
-		result, err := shouldRun(sp.If)
-		if err != nil {
-			// This shouldn't give an error because we evaluate it in Compile.
-			panic(err)
-		}
-		if !result {
-			log.Infof("skipping subpackage %s because %s == false", sp.Name, sp.If)
-		}
-
-		return !result
-	})
+	b.Configuration.Subpackages = filterSubpackages(ctx, b.Configuration.Subpackages, b.Arch)
 
 	// Initialize SBOMGroup for the main package and all subpackages
 	pkgNames := []string{b.Configuration.Package.Name}

pkg/build/compile_test.go

@@ -121,6 +121,28 @@ func TestCompileTest(t *testing.T) {
 	}
 }
 
+func TestFilterSubpackagesTargetArchitecture(t *testing.T) {
+	subpackages := []config.Subpackage{
+		{Name: "default"},
+		{Name: "all", TargetArchitecture: []string{"all"}},
+		{Name: "native", TargetArchitecture: []string{"x86_64"}},
+		{Name: "other", TargetArchitecture: []string{"aarch64"}},
+	}
+
+	got := filterSubpackages(context.Background(), subpackages, apko_types.ParseArchitecture("x86_64"))
+	if got, want := packageNames(got), []string{"default", "all", "native"}; !slices.Equal(got, want) {
+		t.Errorf("subpackage names: want %v, got %v", want, got)
+	}
+}
+
+func packageNames(subpackages []config.Subpackage) []string {
+	names := make([]string, 0, len(subpackages))
+	for _, sp := range subpackages {
+		names = append(names, sp.Name)
+	}
+	return names
+}
+
 func Test_stripComments(t *testing.T) {
 	tests := []struct {
 		in, want string

pkg/build/test.go

@@ -22,7 +22,6 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
-	"slices"
 	"time"
 
 	"chainguard.dev/apko/pkg/apk/apk"
@@ -251,19 +250,7 @@ func (t *Test) TestPackage(ctx context.Context) error {
 		return fmt.Errorf("compiling %s tests: %w", t.ConfigFile, err)
 	}
 
-	// Filter out any subpackages with false If conditions.
-	t.Configuration.Subpackages = slices.DeleteFunc(t.Configuration.Subpackages, func(sp config.Subpackage) bool {
-		result, err := shouldRun(sp.If)
-		if err != nil {
-			// This shouldn't give an error because we evaluate it in Compile.
-			panic(err)
-		}
-		if !result {
-			log.Infof("skipping subpackage %s because %s == false", sp.Name, sp.If)
-		}
-
-		return !result
-	})
+	t.Configuration.Subpackages = filterSubpackages(ctx, t.Configuration.Subpackages, t.Arch)
 
 	// Unless a specific architecture is requests, we run the test for all.
 	inarchs := len(pkg.TargetArchitecture) == 0

pkg/config/config.go

@@ -861,6 +861,8 @@ type Subpackage struct {
 	URL string `json:"url,omitempty" yaml:"url,omitempty"`
 	// Optional: The git commit of the subpackage build configuration
 	Commit string `json:"commit,omitempty" yaml:"commit,omitempty"`
+	// List of target architectures for which this subpackage should be built
+	TargetArchitecture []string `json:"target-architecture,omitempty" yaml:"target-architecture,omitempty"`
 	// Optional: enabling, disabling, and configuration of build checks
 	Checks Checks `json:"checks" yaml:"checks,omitempty"`
 	// Test section for the subpackage.
@@ -1551,17 +1553,18 @@ func replacePackage(r *strings.Replacer, commit string, in Package) Package {
 
 func replaceSubpackage(r *strings.Replacer, detectedCommit string, in Subpackage) Subpackage {
 	return Subpackage{
-		If:           r.Replace(in.If),
-		Name:         r.Replace(in.Name),
-		Pipeline:     replacePipelines(r, in.Pipeline),
-		Dependencies: replaceDependencies(r, in.Dependencies),
-		Options:      in.Options,
-		Scriptlets:   replaceScriptlets(r, in.Scriptlets),
-		Description:  r.Replace(in.Description),
-		URL:          r.Replace(in.URL),
-		Commit:       replaceCommit(detectedCommit, in.Commit),
-		Checks:       in.Checks,
-		Test:         replaceTest(r, in.Test),
+		If:                 r.Replace(in.If),
+		Name:               r.Replace(in.Name),
+		Pipeline:           replacePipelines(r, in.Pipeline),
+		Dependencies:       replaceDependencies(r, in.Dependencies),
+		Options:            in.Options,
+		Scriptlets:         replaceScriptlets(r, in.Scriptlets),
+		Description:        r.Replace(in.Description),
+		URL:                r.Replace(in.URL),
+		Commit:             replaceCommit(detectedCommit, in.Commit),
+		TargetArchitecture: replaceAll(r, in.TargetArchitecture),
+		Checks:             in.Checks,
+		Test:               replaceTest(r, in.Test),
 	}
 }
 

pkg/config/config_test.go

@@ -98,6 +98,7 @@ environment:
 vars:
   foo: FOO
   bar: BAR
+  arch: x86_64
 
 var-transforms:
   - from: ${{package.version}}
@@ -107,6 +108,8 @@ var-transforms:
 
 subpackages:
   - name: subpackage-${{vars.short-package-version}}
+    target-architecture:
+      - ${{vars.arch}}
     dependencies:
       runtime:
         - ${{package.name}}-config-${{package.version}}
@@ -181,6 +184,7 @@ test:
 	}, cfg.Test.Environment.Contents.Packages)
 
 	require.Equal(t, cfg.Subpackages[0].Name, "subpackage-0.0")
+	require.Equal(t, []string{"x86_64"}, cfg.Subpackages[0].TargetArchitecture)
 
 	require.Equal(t, "/usr/local/FOO", cfg.Test.Environment.Environment["LD_LIBRARY_PATH"])
 }

pkg/config/schema.cue

@@ -567,6 +567,10 @@
 	// Optional: The git commit of the subpackage build configuration
 	commit?: string
 
+	// List of target architectures for which this subpackage should be
+	// built
+	"target-architecture"?: [...string]
+
 	// Optional: enabling, disabling, and configuration of build
 	// checks
 	checks!: #Checks

pkg/config/schema.json

@@ -1033,6 +1033,13 @@
           "type": "string",
           "description": "Optional: The git commit of the subpackage build configuration"
         },
+        "target-architecture": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array",
+          "description": "List of target architectures for which this subpackage should be built"
+        },
         "checks": {
           "$ref": "#/$defs/Checks",
           "description": "Optional: enabling, disabling, and configuration of build checks"