Show commit hash in actuator endpoint

Include the current commit hash in the "Info" actuator endpoint

app/build.gradle.kts

@@ -1,4 +1,5 @@
 import org.springframework.boot.gradle.tasks.run.BootRun
+import java.io.ByteArrayOutputStream
 
 plugins {
     `java-convention`
@@ -30,13 +31,21 @@ tasks.getByName<BootRun>("bootRun") {
     args = listOf("--spring.profiles.active=dev")
 }
 
+val shortCommitHash by tasks.registering(Exec::class) {
+    commandLine("git", "rev-parse", "--short", "HEAD")
+    standardOutput = ByteArrayOutputStream()
+}
+
 springBoot {
     buildInfo {
         properties {
+            additional = mapOf("commit" to DelegatingProvider(shortCommitHash.map { it.standardOutput.toString().trim() }))
             time = null
             artifact = ""
             group = ""
             name = ""
         }
+
+        dependsOn(shortCommitHash)
     }
 }

buildSrc/src/main/java/DelegatingProvider.java

@@ -0,0 +1,93 @@
+import java.io.Serializable;
+import java.util.function.BiFunction;
+
+import org.gradle.api.Transformer;
+import org.gradle.api.provider.Provider;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Spring Boot's {@code BuildInfo} Task calls the {@link Object#toString() toString} Method on every value present in
+ * the Map of the additional build information properties at task execution time. Therefore, a normal Gradle
+ * {@link Provider} does not work, since the {@link Object#toString() toString} method does not return the String
+ * representation of the provided value.
+ *
+ * @implNote Instances of this class must be serializable. Gradle will reject unserializable input properties when
+ * calculating the input's fingerprint.
+ */
+public class DelegatingProvider<T extends Serializable> implements Provider<T>, Serializable {
+
+    /**
+     * @implNote Marking this property as transient is not an ideal solution, but the only type-safe one, since
+     * {@link Provider} does not implement {@link Serializable}.
+     */
+    private final transient Provider<T> delegate;
+
+    /**
+     * @param delegate
+     *     The provider all operations are delegated to, not {@code null}.
+     */
+    public DelegatingProvider(Provider<T> delegate) {
+        this.delegate = delegate;
+    }
+
+    /**
+     * @return The string representation of the contained value.
+     */
+    @Override
+    public String toString() {
+        return delegate.get().toString();
+    }
+
+    @Override
+    public T get() {
+        return delegate.get();
+    }
+
+    @Nullable
+    @Override
+    public T getOrNull() {
+        return delegate.getOrNull();
+    }
+
+    @Override
+    public T getOrElse(T defaultValue) {
+        return delegate.getOrElse(defaultValue);
+    }
+
+    @Override
+    public <S> Provider<S> map(Transformer<? extends S, ? super T> transformer) {
+        return delegate.map(transformer);
+    }
+
+    @Override
+    public <S> Provider<S> flatMap(Transformer<? extends Provider<? extends S>, ? super T> transformer) {
+        return delegate.flatMap(transformer);
+    }
+
+    @Override
+    public boolean isPresent() {
+        return delegate.isPresent();
+    }
+
+    @Override
+    public Provider<T> orElse(T value) {
+        return delegate.orElse(value);
+    }
+
+    @Override
+    public Provider<T> orElse(Provider<? extends T> provider) {
+        return delegate.orElse(provider);
+    }
+
+    @Override
+    @Deprecated
+    public Provider<T> forUseAtConfigurationTime() {
+        return delegate.forUseAtConfigurationTime();
+    }
+
+    @Override
+    public <B, R> Provider<R> zip(Provider<B> provider, BiFunction<T, B, R> biFunction) {
+        return delegate.zip(provider, biFunction);
+    }
+
+}

buildSrc/src/main/kotlin/java-convention.gradle.kts

@@ -11,7 +11,6 @@ repositories {
 
 java {
     sourceCompatibility = JavaVersion.VERSION_17
-    targetCompatibility = JavaVersion.VERSION_17
 }
 
 val integrationTestImplementation by configurations.creating
@@ -40,19 +39,17 @@ dependencies {
     testImplementation("org.mockito:mockito-junit-jupiter")
 }
 
-sourceSets {
-    create("integrationTest") {
-        compileClasspath += sourceSets.main.get().output
-        runtimeClasspath += sourceSets.main.get().output
-    }
+val integrationTestSourceSet by sourceSets.creating {
+    compileClasspath += sourceSets.main.get().output
+    runtimeClasspath += sourceSets.main.get().output
 }
 
-val integrationTest = task<Test>("integrationTest") {
+val integrationTest by tasks.registering(Test::class) {
     group = "verification"
 
-    testClassesDirs = sourceSets["integrationTest"].output.classesDirs
-    classpath = sourceSets["integrationTest"].runtimeClasspath
-    shouldRunAfter("test")
+    testClassesDirs = integrationTestSourceSet.output.classesDirs
+    classpath = integrationTestSourceSet.runtimeClasspath
+    shouldRunAfter(tasks.test)
 }
 
 tasks.withType<Test> {