Packaging improvement

docs/src/main/asciidoc/gcp-functions-http.adoc

@@ -142,33 +142,18 @@ public class GreetingRoutes {
 
 == Build and Deploy to Google Cloud
 
-To build your application, you first need to define a packaging of type `uber-jar` via your `application.properties`.
-
-[source]
-----
-quarkus.package.uber-jar=true
-----
+NOTE: Quarkus forces a packaging of type `uber-jar` for your function as Google Cloud Function deployment requires a single JAR.
 
 Package your application using the standard `mvn clean package` command.
-The result of the previous command is a single JAR file inside the `target` repository that contains classes and dependencies of the project.
-
-To deploy your JAR to Google Cloud, you need to pass a directory with only this JAR inside it, to the `gcloud` utility.
-
-So first, create a `deployment` directory and copy the generated artifact inside it.
-
-[source]
-----
-mkdir deployment
-cp target/google-cloud-functions-http-1.0-SNAPSHOT-runner.jar deployment/
-----
+The result of the previous command is a single JAR file inside the `target/deployment` directory that contains the classes and the dependencies of the project.
 
 Then you will be able to use `gcloud` to deploy your function to Google Cloud.
 
 [source]
 ----
 gcloud beta functions deploy quarkus-example-http \
   --entry-point=io.quarkus.gcp.functions.http.QuarkusHttpFunction \
-  --runtime=java11 --trigger-http --source=deployment
+  --runtime=java11 --trigger-http --source=target/deployment
 ----
 
 [IMPORTANT]
@@ -213,7 +198,7 @@ Then you can use it to launch your function locally.
 [source]
 ----
 java -jar java-function-invoker-1.0.0-beta1.jar \
-  --classpath target/google-cloud-functions-http-1.0-SNAPSHOT-runner.jar \
+  --classpath target/deployment/google-cloud-functions-http-1.0-SNAPSHOT-runner.jar \
   --target io.quarkus.gcp.functions.http.QuarkusHttpFunction
 ----
 

extensions/google-cloud-functions-http/deployment/src/main/java/io/quarkus/gcp/functions/http/deployment/CloudFunctionsDeploymentBuildStep.java

@@ -0,0 +1,49 @@
+package io.quarkus.gcp.functions.http.deployment;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Collections;
+
+import io.quarkus.builder.BuildException;
+import io.quarkus.deployment.IsNormal;
+import io.quarkus.deployment.annotations.BuildStep;
+import io.quarkus.deployment.pkg.builditem.ArtifactResultBuildItem;
+import io.quarkus.deployment.pkg.builditem.JarBuildItem;
+import io.quarkus.deployment.pkg.builditem.OutputTargetBuildItem;
+import io.quarkus.deployment.pkg.builditem.UberJarRequiredBuildItem;
+import io.quarkus.deployment.pkg.steps.NativeBuild;
+
+public class CloudFunctionsDeploymentBuildStep {
+    @BuildStep
+    public UberJarRequiredBuildItem forceUberJar() {
+        // Google Cloud Function needs a single JAR inside a dedicated directory
+        return new UberJarRequiredBuildItem();
+    }
+
+    /**
+     * Creates a target/deployment dir and copy the uber jar in it.
+     * This facilitates the usage of the 'glcoud' command.
+     */
+    @BuildStep(onlyIf = IsNormal.class, onlyIfNot = NativeBuild.class)
+    public ArtifactResultBuildItem functionDeployment(OutputTargetBuildItem target, JarBuildItem jar)
+            throws BuildException, IOException {
+        if (!jar.isUberJar()) {
+            throw new BuildException("Google Cloud Function deployment need to use a uberjar, " +
+                    "please set 'quarkus.package.uber-jar=true' inside your application.properties",
+                    Collections.EMPTY_LIST);
+        }
+
+        Path deployment = target.getOutputDirectory().resolve("deployment");
+        if (Files.notExists(deployment)) {
+            Files.createDirectory(deployment);
+        }
+
+        Path jarPath = jar.getPath();
+        Path targetJarPath = deployment.resolve(jarPath.getFileName());
+        Files.deleteIfExists(targetJarPath);
+        Files.copy(jarPath, targetJarPath);
+
+        return new ArtifactResultBuildItem(targetJarPath, "function", Collections.EMPTY_MAP);
+    }
+}

integration-tests/google-cloud-functions-http/src/main/resources/application.properties

@@ -1 +0,0 @@
-quarkus.package.uber-jar=true