Set up the plugin build environment

The goal of this CL is to set up the build environment to allow plugins to work.

We have a trivial plugin that doesn't do anything (yet) - it just sets itself as the finalizer of all Reporting tasks.

Eventually, this plugin will upload all reports to GCS, and even create a "cover page" linking to each one of them.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=233617499

gradle/build.gradle

@@ -37,6 +37,12 @@ plugins {
   id "com.moowork.node" version "1.2.0"
 }
 
+apply plugin: google.registry.gradle.plugin.GcsReportUploaderPlugin
+
+gcsReportUploader {
+  bucket = 'my-bucket'
+}
+
 apply from: 'dependencies.gradle'
 
 // Provide defaults for all of the project properties.

gradle/buildSrc/build.gradle

@@ -0,0 +1,21 @@
+
+repositories {
+  if (project.ext.properties.repositoryUrl == null) {
+    println "Plugins: Using Maven central..."
+    mavenCentral()
+  } else {
+    maven {
+      println "Plugins: Using repo ${repositoryUrl}..."
+      url repositoryUrl
+    }
+  }
+}
+
+apply from: '../dependencies.gradle'
+
+
+dependencies {
+  def deps = dependencyMap
+  compile deps['com.google.guava:guava']
+  testCompile deps['com.google.truth:truth']
+}

gradle/buildSrc/src/main/java/google/registry/gradle/plugin/GcsReportUploader.java

@@ -0,0 +1,56 @@
+// Copyright 2019 The Nomulus Authors. All Rights Reserved.
+//
+// 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
+//
+//     http://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 google.registry.gradle.plugin;
+
+import java.util.ArrayList;
+import org.gradle.api.DefaultTask;
+import org.gradle.api.Task;
+import org.gradle.api.reporting.Report;
+import org.gradle.api.reporting.ReportContainer;
+import org.gradle.api.reporting.Reporting;
+import org.gradle.api.tasks.TaskAction;
+
+/**
+ * A task that uploads the Reports generated by other tasks to GCS.
+ *
+ * <p>TODO:implement it.
+ */
+public class GcsReportUploader extends DefaultTask {
+
+  private final ArrayList<Task> reportingTasks = new ArrayList<>();
+
+  private String bucket = null;
+
+  public void setBucket(String bucket) {
+    this.bucket = bucket;
+  }
+
+  @TaskAction
+  void uploadResults() {
+    System.out.format("GcsReportUploader uploading to %s: Unimplemented\n", bucket);
+  }
+
+  private static Reporting<? extends ReportContainer<? extends Report>> asReporting(Task task) {
+    return (Reporting) task;
+  }
+
+  void addTask(Task task) {
+    if (!(task instanceof Reporting)) {
+      return;
+    }
+    reportingTasks.add(task);
+    task.finalizedBy(this);
+  }
+}

gradle/buildSrc/src/main/java/google/registry/gradle/plugin/GcsReportUploaderPlugin.java

@@ -0,0 +1,43 @@
+// Copyright 2019 The Nomulus Authors. All Rights Reserved.
+//
+// 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
+//
+//     http://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 google.registry.gradle.plugin;
+
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+
+/**
+ * Plugin setting up the GcsReportUploader task.
+ *
+ * <p>It goes over all the tasks in a project and pass them on to the GcsReportUploader task for set
+ * up.
+ *
+ * <p>Note that since we're passing in all the projects' tasks - this includes the GcsReportUploader
+ * itself! It's up to the GcsReportuploader to take care of not having "infinite loops" caused by
+ * waiting for itself to end before finishing.
+ */
+public class GcsReportUploaderPlugin implements Plugin<Project> {
+
+  public void apply(Project project) {
+    GcsReportUploader reportUploader =
+        project.getTasks().create("gcsReportUploader", GcsReportUploader.class, task -> {
+          task.setDescription("Uploads the reports to GCS bucket");
+          task.setGroup("uploads");
+        });
+
+    for (Project subProject : project.getAllprojects()) {
+      subProject.getTasks().all(reportUploader::addTask);
+    }
+  }
+}