Merge pull request #171 from paketo-buildpacks/sdkman

Support SDKMAN RC files

build.go

@@ -55,7 +55,7 @@ func (b Build) Build(context libcnb.BuildContext) (libcnb.BuildResult, error) {
 	cl := NewCertificateLoader()
 	cl.Logger = b.Logger.BodyWriter()
 
-	jvmVersion := JVMVersion{Logger: b.Logger}
+	jvmVersion := NewJVMVersion(b.Logger)
 	v, err := jvmVersion.GetJVMVersion(context.Application.Path, cr)
 	if err != nil {
 		return libcnb.BuildResult{}, fmt.Errorf("unable to determine jvm version\n%w", err)

init_test.go

@@ -41,6 +41,7 @@ func TestUnit(t *testing.T) {
 	suite("NewManifest", testNewManifest)
 	suite("NewManifestFromJAR", testNewManifestFromJAR)
 	suite("MavenJARListing", testMavenJARListing)
+	suite("SDKMAN", testSDKMAN)
 	suite("Versions", testVersions)
 	suite("JVMVersions", testJVMVersion)
 	suite.Run(t)

jvm_version.go

@@ -1,6 +1,10 @@
 package libjvm
 
 import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/heroku/color"
@@ -12,36 +16,76 @@ type JVMVersion struct {
 	Logger bard.Logger
 }
 
-func (jvmVersion JVMVersion) GetJVMVersion(appPath string, cr libpak.ConfigurationResolver) (string, error) {
+func NewJVMVersion(logger bard.Logger) JVMVersion {
+	return JVMVersion{Logger: logger}
+}
+
+func (j JVMVersion) GetJVMVersion(appPath string, cr libpak.ConfigurationResolver) (string, error) {
 	version, explicit := cr.Resolve("BP_JVM_VERSION")
+	if explicit {
+		f := color.New(color.Faint)
+		j.Logger.Body(f.Sprintf("Using Java version %s from BP_JVM_VERSION", version))
+		return version, nil
+	}
 
-	if !explicit {
-		manifest, err := NewManifest(appPath)
-		if err != nil {
-			return version, err
-		}
+	sdkmanrcJavaVersion, err := readJavaVersionFromSDKMANRCFile(appPath)
+	if err != nil {
+		return "", fmt.Errorf("unable to read Java version from SDMANRC file\n%w", err)
+	}
 
-		javaVersion := ""
+	if len(sdkmanrcJavaVersion) > 0 {
+		sdkmanrcJavaMajorVersion := extractMajorVersion(sdkmanrcJavaVersion)
+		f := color.New(color.Faint)
+		j.Logger.Body(f.Sprintf("Using Java version %s extracted from .sdkmanrc", sdkmanrcJavaMajorVersion))
+		return sdkmanrcJavaMajorVersion, nil
+	}
 
-		buildJdkSpecVersion, ok := manifest.Get("Build-Jdk-Spec")
-		if ok {
-			javaVersion = buildJdkSpecVersion
-		}
+	mavenJavaVersion, err := readJavaVersionFromMavenMetadata(appPath)
+	if err != nil {
+		return "", fmt.Errorf("unable to read Java version from Maven metadata\n%w", err)
+	}
 
-		buildJdkVersion, ok := manifest.Get("Build-Jdk")
-		if ok {
-			javaVersion = buildJdkVersion
-		}
+	if len(mavenJavaVersion) > 0 {
+		mavenJavaMajorVersion := extractMajorVersion(mavenJavaVersion)
+		f := color.New(color.Faint)
+		j.Logger.Body(f.Sprintf("Using Java version %s extracted from MANIFEST.MF", mavenJavaMajorVersion))
+		return mavenJavaMajorVersion, nil
+	}
+
+	f := color.New(color.Faint)
+	j.Logger.Body(f.Sprintf("Using buildpack default Java version %s", version))
+	return version, nil
+}
+
+func readJavaVersionFromSDKMANRCFile(appPath string) (string, error) {
+	components, err := ReadSDKMANRC(filepath.Join(appPath, ".sdkmanrc"))
+	if err != nil && errors.Is(err, os.ErrNotExist) {
+		return "", nil
+	} else if err != nil {
+		return "", err
+	}
 
-		if len(javaVersion) > 0 {
-			javaVersionFromMaven := extractMajorVersion(javaVersion)
-			f := color.New(color.Faint)
-			jvmVersion.Logger.Body(f.Sprintf("Using Java version %s extracted from MANIFEST.MF", javaVersionFromMaven))
-			return javaVersionFromMaven, nil
+	for _, component := range components {
+		if component.Type == "java" {
+			return component.Version, nil
 		}
 	}
 
-	return version, nil
+	return "", nil
+}
+
+func readJavaVersionFromMavenMetadata(appPath string) (string, error) {
+	manifest, err := NewManifest(appPath)
+	if err != nil {
+		return "", err
+	}
+
+	javaVersion, ok := manifest.Get("Build-Jdk-Spec")
+	if !ok {
+		javaVersion, _ = manifest.Get("Build-Jdk")
+	}
+
+	return javaVersion, nil
 }
 
 func extractMajorVersion(version string) string {

jvm_version_test.go

@@ -17,13 +17,14 @@
 package libjvm_test
 
 import (
-	"github.com/paketo-buildpacks/libpak"
-	"github.com/paketo-buildpacks/libpak/bard"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
 
+	"github.com/paketo-buildpacks/libpak"
+	"github.com/paketo-buildpacks/libpak/bard"
+
 	"github.com/buildpacks/libcnb"
 	. "github.com/onsi/gomega"
 	"github.com/sclevine/spec"
@@ -40,6 +41,11 @@ func testJVMVersion(t *testing.T, context spec.G, it spec.S) {
 	)
 
 	it.Before(func() {
+		var err error
+
+		appPath, err = ioutil.TempDir("", "application")
+		Expect(err).NotTo(HaveOccurred())
+
 		buildpack = libcnb.Buildpack{
 			Metadata: map[string]interface{}{
 				"configurations": []map[string]interface{}{
@@ -53,6 +59,10 @@ func testJVMVersion(t *testing.T, context spec.G, it spec.S) {
 		logger = bard.NewLogger(ioutil.Discard)
 	})
 
+	it.After(func() {
+		Expect(os.RemoveAll(appPath)).To(Succeed())
+	})
+
 	it("detecting JVM version from default", func() {
 		jvmVersion := libjvm.JVMVersion{Logger: logger}
 
@@ -85,13 +95,7 @@ func testJVMVersion(t *testing.T, context spec.G, it spec.S) {
 
 	context("detecting JVM version", func() {
 		it.Before(func() {
-			temp, err := prepareAppWithEntry("Build-Jdk: 1.8")
-			Expect(err).ToNot(HaveOccurred())
-			appPath = temp
-		})
-
-		it.After(func() {
-			os.RemoveAll(appPath)
+			Expect(prepareAppWithEntry(appPath, "Build-Jdk: 1.8")).ToNot(HaveOccurred())
 		})
 
 		it("from manifest via Build-Jdk-Spec", func() {
@@ -108,14 +112,11 @@ func testJVMVersion(t *testing.T, context spec.G, it spec.S) {
 	context("detecting JVM version", func() {
 		it.Before(func() {
 			Expect(os.Setenv("BP_JVM_VERSION", "17")).To(Succeed())
-			temp, err := prepareAppWithEntry("Build-Jdk: 1.8")
-			Expect(err).ToNot(HaveOccurred())
-			appPath = temp
+			Expect(prepareAppWithEntry(appPath, "Build-Jdk: 1.8")).ToNot(HaveOccurred())
 		})
 
 		it.After(func() {
 			Expect(os.Unsetenv("BP_JVM_VERSION")).To(Succeed())
-			os.RemoveAll(appPath)
 		})
 
 		it("prefers environment variable over manifest", func() {
@@ -129,22 +130,56 @@ func testJVMVersion(t *testing.T, context spec.G, it spec.S) {
 		})
 	})
 
+	context("detecting JVM version", func() {
+		var sdkmanrcFile string
+
+		it.Before(func() {
+			sdkmanrcFile = filepath.Join(appPath, ".sdkmanrc")
+			Expect(ioutil.WriteFile(sdkmanrcFile, []byte(`java=17.0.2-tem`), 0644)).To(Succeed())
+		})
+
+		it("from .sdkmanrc file", func() {
+			jvmVersion := libjvm.JVMVersion{Logger: logger}
+
+			cr, err := libpak.NewConfigurationResolver(buildpack, &logger)
+			Expect(err).ToNot(HaveOccurred())
+			version, err := jvmVersion.GetJVMVersion(appPath, cr)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(version).To(Equal("17"))
+		})
+	})
+
+	context("detecting JVM version", func() {
+		var sdkmanrcFile string
+
+		it.Before(func() {
+			sdkmanrcFile = filepath.Join(appPath, ".sdkmanrc")
+			Expect(ioutil.WriteFile(sdkmanrcFile, []byte(`java=17.0.2-tem
+java=11.0.2-tem`), 0644)).To(Succeed())
+		})
+
+		it("picks first from .sdkmanrc file if there are multiple", func() {
+			jvmVersion := libjvm.JVMVersion{Logger: logger}
+
+			cr, err := libpak.NewConfigurationResolver(buildpack, &logger)
+			Expect(err).ToNot(HaveOccurred())
+			version, err := jvmVersion.GetJVMVersion(appPath, cr)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(version).To(Equal("17"))
+		})
+	})
 }
 
-func prepareAppWithEntry(entry string) (string, error) {
-	temp, err := ioutil.TempDir("", "jre-app")
-	if err != nil {
-		return "", err
-	}
-	err = os.Mkdir(filepath.Join(temp, "META-INF"), 0744)
+func prepareAppWithEntry(appPath, entry string) error {
+	err := os.Mkdir(filepath.Join(appPath, "META-INF"), 0744)
 	if err != nil {
-		return "", err
+		return err
 	}
-	manifest := filepath.Join(temp, "META-INF", "MANIFEST.MF")
+	manifest := filepath.Join(appPath, "META-INF", "MANIFEST.MF")
 	manifestContent := []byte(entry)
 	err = ioutil.WriteFile(manifest, manifestContent, 0644)
 	if err != nil {
-		return "", err
+		return err
 	}
-	return temp, nil
+	return nil
 }

sdkman.go

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2018-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package libjvm
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strings"
+)
+
+// SDKInfo represents the information from each line in the `.sdkmanrc` file
+type SDKInfo struct {
+	Type    string
+	Version string
+	Vendor  string
+}
+
+// ReadSDKMANRC reads the `.sdkmanrc` format file from path and retuns the list of SDKS in it
+func ReadSDKMANRC(path string) ([]SDKInfo, error) {
+	sdkmanrcContents, err := ioutil.ReadFile(path)
+	if err != nil {
+		return []SDKInfo{}, fmt.Errorf("unable to read SDKMANRC file at %s\n%w", path, err)
+	}
+
+	sdks := []SDKInfo{}
+	for _, line := range strings.Split(string(sdkmanrcContents), "\n") {
+		if strings.TrimSpace(line) == "" {
+			continue
+		}
+
+		parts := strings.SplitN(line, "#", 2) // strip comments
+		if len(parts) != 1 && len(parts) != 2 {
+			return []SDKInfo{}, fmt.Errorf("unable to strip comments from %q resulted in %q", line, parts)
+		}
+
+		if strings.TrimSpace(parts[0]) != "" {
+			kv := strings.SplitN(parts[0], "=", 2) // split key=value
+			if len(kv) != 2 {
+				return []SDKInfo{}, fmt.Errorf("unable to split key/value from %q resulted in %q", parts[0], kv)
+			}
+
+			versionAndVendor := []string{"", ""}
+			if strings.TrimSpace(kv[1]) != "" {
+				versionAndVendor = strings.SplitN(kv[1], "-", 2) // split optional vendor name
+				if len(versionAndVendor) == 1 {
+					versionAndVendor = append(versionAndVendor, "")
+				}
+				if len(versionAndVendor) != 2 {
+					return []SDKInfo{}, fmt.Errorf("unable to split vendor from %q resulted in %q", kv[1], versionAndVendor)
+				}
+			}
+
+			sdks = append(sdks, SDKInfo{
+				Type:    strings.ToLower(strings.TrimSpace(kv[0])),
+				Version: strings.TrimSpace(versionAndVendor[0]),
+				Vendor:  strings.ToLower(strings.TrimSpace(versionAndVendor[1])),
+			})
+		}
+	}
+
+	return sdks, nil
+}