feat: add support for Gradle

bin/.gradle-8.9.pkg

@@ -0,0 +1 @@
+hermit

bin/gradle

@@ -0,0 +1 @@
+.gradle-8.9.pkg

internal/buildengine/build_java.go

@@ -10,14 +10,17 @@ import (
 	"github.com/TBD54566975/ftl"
 	"github.com/TBD54566975/ftl/internal/exec"
 	"github.com/TBD54566975/ftl/internal/log"
+	"github.com/TBD54566975/ftl/internal/moduleconfig"
 )
 
 func buildJavaModule(ctx context.Context, module Module) error {
 	logger := log.FromContext(ctx)
-	if err := SetPOMProperties(ctx, module.Config.Dir); err != nil {
-		// This is not a critical error, things will probably work fine
-		// TBH updating the pom is maybe not the best idea anyway
-		logger.Warnf("unable to update ftl.version in %s: %s", module.Config.Dir, err.Error())
+	if module.Config.Java.BuildTool == moduleconfig.JavaBuildToolMaven {
+		if err := SetPOMProperties(ctx, module.Config.Dir); err != nil {
+			// This is not a critical error, things will probably work fine
+			// TBH updating the pom is maybe not the best idea anyway
+			logger.Warnf("unable to update ftl.version in %s: %s", module.Config.Dir, err.Error())
+		}
 	}
 	logger.Infof("Using build command '%s'", module.Config.Build)
 	err := exec.Command(ctx, log.Debug, module.Config.Dir, "bash", "-c", module.Config.Build).RunBuffered(ctx)

internal/buildengine/discover_test.go

@@ -87,6 +87,9 @@ func TestDiscoverModules(t *testing.T) {
 					"src/**",
 					"target/generated-sources",
 				},
+				Java: moduleconfig.ModuleJavaConfig{
+					BuildTool: "maven",
+				},
 			},
 		},
 		{
@@ -129,6 +132,9 @@ func TestDiscoverModules(t *testing.T) {
 					"src/**",
 					"target/generated-sources",
 				},
+				Java: moduleconfig.ModuleJavaConfig{
+					BuildTool: "maven",
+				},
 			},
 		},
 		{

internal/moduleconfig/moduleconfig.go

@@ -22,7 +22,12 @@ type ModuleGoConfig struct{}
 type ModuleKotlinConfig struct{}
 
 // ModuleJavaConfig is language-specific configuration for Java modules.
-type ModuleJavaConfig struct{}
+type ModuleJavaConfig struct {
+	BuildTool string `toml:"build-tool"`
+}
+
+const JavaBuildToolMaven string = "maven"
+const JavaBuildToolGradle string = "gradle"
 
 // ModuleConfig is the configuration for an FTL module.
 //
@@ -130,21 +135,40 @@ func setConfigDefaults(moduleDir string, config *ModuleConfig) error {
 	}
 	switch config.Language {
 	case "kotlin", "java":
+
 		if config.Build == "" {
-			config.Build = "mvn -B package"
-		}
-		if config.DeployDir == "" {
-			config.DeployDir = "target"
+			pom := filepath.Join(moduleDir, "pom.xml")
+			buildGradle := filepath.Join(moduleDir, "build.gradle")
+			buildGradleKts := filepath.Join(moduleDir, "build.gradle.kts")
+			if config.Java.BuildTool == JavaBuildToolMaven || fileExists(pom) {
+				config.Java.BuildTool = JavaBuildToolMaven
+				config.Build = "mvn -B package"
+				if config.DeployDir == "" {
+					config.DeployDir = "target"
+				}
+				if len(config.Watch) == 0 {
+					config.Watch = []string{"pom.xml", "src/**", "target/generated-sources"}
+				}
+			} else if config.Java.BuildTool == JavaBuildToolGradle || fileExists(buildGradle) || fileExists(buildGradleKts) {
+				config.Java.BuildTool = JavaBuildToolGradle
+				config.Build = "gradle build"
+				if config.DeployDir == "" {
+					config.DeployDir = "build"
+				}
+				if len(config.Watch) == 0 {
+					config.Watch = []string{"pom.xml", "src/**", "build/generated"}
+				}
+			} else {
+				return fmt.Errorf("could not find JVM build file in %s", moduleDir)
+			}
 		}
+
 		if config.GeneratedSchemaDir == "" {
 			config.GeneratedSchemaDir = "src/main/ftl-module-schema"
 		}
 		if len(config.Deploy) == 0 {
 			config.Deploy = []string{"main", "quarkus-app"}
 		}
-		if len(config.Watch) == 0 {
-			config.Watch = []string{"pom.xml", "src/**", "target/generated-sources"}
-		}
 	case "go":
 		if config.DeployDir == "" {
 			config.DeployDir = ".ftl"
@@ -178,17 +202,22 @@ func setConfigDefaults(moduleDir string, config *ModuleConfig) error {
 
 	// Do some validation.
 	if !isBeneath(moduleDir, config.DeployDir) {
-		return fmt.Errorf("deploy-dir must be relative to the module directory")
+		return fmt.Errorf("deploy-dir %s must be relative to the module directory %s", config.DeployDir, moduleDir)
 	}
 	for _, deploy := range config.Deploy {
 		if !isBeneath(moduleDir, deploy) {
-			return fmt.Errorf("deploy files must be relative to the module directory")
+			return fmt.Errorf("deploy %s files must be relative to the module directory %s", deploy, moduleDir)
 		}
 	}
 
 	return nil
 }
 
+func fileExists(filename string) bool {
+	_, err := os.Stat(filename)
+	return err == nil
+}
+
 func isBeneath(moduleDir, path string) bool {
 	resolved := filepath.Clean(filepath.Join(moduleDir, path))
 	return strings.HasPrefix(resolved, strings.TrimSuffix(moduleDir, "/")+"/")

jvm-runtime/jvm_integration_test.go

@@ -114,6 +114,17 @@ func TestJVMToGoCall(t *testing.T) {
 	)
 }
 
+func TestGradle(t *testing.T) {
+	in.Run(t,
+		in.WithLanguages("java"),
+		in.CopyModule("gradle"),
+		in.Deploy("gradle"),
+		in.Call("gradle", "echo", "Bob", func(t testing.TB, response string) {
+			assert.Equal(t, "Hello, Bob!", response)
+		}),
+	)
+}
+
 func PairedTest(name string, testFunc func(module string) in.Action) []in.SubTest {
 	return []in.SubTest{
 		{

jvm-runtime/testdata/java/gradle/build.gradle.kts

@@ -0,0 +1,36 @@
+plugins {
+    java
+    id("io.quarkus")
+}
+
+repositories {
+    mavenCentral()
+    mavenLocal()
+}
+
+val quarkusPlatformGroupId: String by project
+val quarkusPlatformArtifactId: String by project
+val quarkusPlatformVersion: String by project
+
+dependencies {
+    implementation(enforcedPlatform("${quarkusPlatformGroupId}:${quarkusPlatformArtifactId}:${quarkusPlatformVersion}"))
+    implementation("xyz.block.ftl:ftl-java-runtime:1.0-SNAPSHOT")
+    testImplementation("io.quarkus:quarkus-junit5")
+    testImplementation("io.rest-assured:rest-assured")
+}
+
+group = "org.acme"
+version = "1.0.0-SNAPSHOT"
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+
+tasks.withType<Test> {
+    systemProperty("java.util.logging.manager", "org.jboss.logmanager.LogManager")
+}
+tasks.withType<JavaCompile> {
+    options.encoding = "UTF-8"
+    options.compilerArgs.add("-parameters")
+}

jvm-runtime/testdata/java/gradle/ftl.toml

@@ -0,0 +1,2 @@
+module = "gradle"
+language = "java"

jvm-runtime/testdata/java/gradle/gradle.properties

@@ -0,0 +1,7 @@
+# Gradle properties
+
+quarkusPluginId=io.quarkus
+quarkusPluginVersion=3.13.2
+quarkusPlatformGroupId=io.quarkus.platform
+quarkusPlatformArtifactId=quarkus-bom
+quarkusPlatformVersion=3.13.2

jvm-runtime/testdata/java/gradle/settings.gradle.kts

@@ -0,0 +1,13 @@
+pluginManagement {
+    val quarkusPluginVersion: String by settings
+    val quarkusPluginId: String by settings
+    repositories {
+        mavenCentral()
+        gradlePluginPortal()
+        mavenLocal()
+    }
+    plugins {
+        id(quarkusPluginId) version quarkusPluginVersion
+    }
+}
+rootProject.name="gradle"

jvm-runtime/testdata/java/gradle/src/main/java/org/acme/EchoVerb.java

@@ -0,0 +1,13 @@
+package org.acme;
+
+import xyz.block.ftl.Export;
+import xyz.block.ftl.Verb;
+
+public class EchoVerb {
+
+    @Export
+    @Verb
+    public String echo(String request) {
+        return "Hello, " + request + "!";
+    }
+}