Add support for ARM64 support in DependencyResolver

This commit adds support to DependencyResolver.Resolve to pick a Dependency and consider the architecture. It looks at either `BP_ARCH` (if set) or `runtime.GOARCH` otherwise. It then compares this to the `arch=` value that is set in PURL. We are using the PURL because it exists already and already contains the arch info. This is opposed to adding a new property to the dependency metadata. We *may* end up doing that still, but this just gets things working more quickly now and we can change this in the future.

Signed-off-by: Daniel Mikusa <[email protected]>

buildpack.go

@@ -18,8 +18,10 @@ package libpak
 
 import (
 	"fmt"
+	"net/url"
 	"os"
 	"reflect"
+	"runtime"
 	"sort"
 	"strconv"
 	"strings"
@@ -506,6 +508,15 @@ func (d *DependencyResolver) Resolve(id string, version string) (BuildpackDepend
 			return BuildpackDependency{}, fmt.Errorf("unable to parse version %s\n%w", c.Version, err)
 		}
 
+		// filter out deps that do not match the current running architecture
+		arch, err := archFromPURL(c.PURL)
+		if err != nil {
+			return BuildpackDependency{}, fmt.Errorf("unable to compare arch\n%w", err)
+		}
+		if arch != archFromSystem() {
+			continue
+		}
+
 		if c.ID == id && vc.Check(v) && d.contains(c.Stacks, d.StackID) {
 			candidates = append(candidates, c)
 		}
@@ -534,6 +545,33 @@ func (d *DependencyResolver) Resolve(id string, version string) (BuildpackDepend
 	return candidate, nil
 }
 
+func archFromPURL(rawPURL string) (string, error) {
+	if len(strings.TrimSpace(rawPURL)) == 0 {
+		return "amd64", nil
+	}
+
+	purl, err := url.Parse(rawPURL)
+	if err != nil {
+		return "", fmt.Errorf("unable to parse PURL\n%w", err)
+	}
+
+	queryParams := purl.Query()
+	if arch, ok := queryParams["arch"]; ok {
+		return arch[0], nil
+	}
+
+	return "amd64", nil
+}
+
+func archFromSystem() string {
+	archFromEnv, ok := os.LookupEnv("BP_ARCH")
+	if !ok {
+		archFromEnv = runtime.GOARCH
+	}
+
+	return archFromEnv
+}
+
 func (DependencyResolver) contains(candidates []string, value string) bool {
 	if len(candidates) == 0 {
 		return true

buildpack_test.go

@@ -282,6 +282,10 @@ func testBuildpack(t *testing.T, context spec.G, it spec.S) {
 			resolver libpak.DependencyResolver
 		)
 
+		it.Before(func() {
+			t.Setenv("BP_ARCH", "amd64") // force for test consistency
+		})
+
 		context("Resolve", func() {
 
 			it("filters by id", func() {
@@ -315,6 +319,42 @@ func testBuildpack(t *testing.T, context spec.G, it spec.S) {
 				}))
 			})
 
+			it("filters by arch", func() {
+				resolver.Dependencies = []libpak.BuildpackDependency{
+					{
+						ID:      "test-id-1",
+						Name:    "test-name",
+						Version: "1.0",
+						URI:     "test-uri-amd64",
+						SHA256:  "test-sha256",
+						Stacks:  []string{"test-stack-1", "test-stack-2"},
+						PURL:    "pkg:generic/[email protected]?arch=amd64",
+					},
+					{
+						ID:      "test-id-1",
+						Name:    "test-name",
+						Version: "1.0",
+						URI:     "test-uri-arm64",
+						SHA256:  "test-sha256",
+						Stacks:  []string{"test-stack-1", "test-stack-2"},
+						PURL:    "pkg:generic/[email protected]?arch=arm64",
+					},
+				}
+				resolver.StackID = "test-stack-1"
+
+				t.Setenv("BP_ARCH", "arm64")
+
+				Expect(resolver.Resolve("test-id-1", "1.0")).To(Equal(libpak.BuildpackDependency{
+					ID:      "test-id-1",
+					Name:    "test-name",
+					Version: "1.0",
+					URI:     "test-uri-arm64",
+					SHA256:  "test-sha256",
+					Stacks:  []string{"test-stack-1", "test-stack-2"},
+					PURL:    "pkg:generic/[email protected]?arch=arm64",
+				}))
+			})
+
 			it("filters by version constraint", func() {
 				resolver.Dependencies = []libpak.BuildpackDependency{
 					{

carton/package.go

@@ -89,7 +89,7 @@ func (p Package) Create(options ...Option) {
 		config.exitHandler.Error(fmt.Errorf("unable to decode buildpack %s\n%w", file, err))
 		return
 	}
-	logger.Debug("Buildpack: %+v", buildpack)
+	logger.Debugf("Buildpack: %+v", buildpack)
 
 	metadata, err := libpak.NewBuildpackMetadata(buildpack.Metadata)
 	if err != nil {
@@ -102,7 +102,7 @@ func (p Package) Create(options ...Option) {
 	for _, i := range metadata.IncludeFiles {
 		entries[i] = filepath.Join(p.Source, i)
 	}
-	logger.Debug("Include files: %+v", entries)
+	logger.Debugf("Include files: %+v", entries)
 
 	if p.Version != "" {
 		buildpack.Info.Version = p.Version