[BEAM-5837] Add initial jenkins job to verify community metrics infra.

This change just creates the Jenkins / Gradle infrastructure for adding
build and test validation for community metrics infrastructure under
.test-infra/metrics

.test-infra/jenkins/job_PreCommit_CommunityMetrics.groovy

+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import PrecommitJobBuilder
+
+PrecommitJobBuilder builder = new PrecommitJobBuilder(
+    scope: this,
+    nameBase: 'Community Metrics',
+    gradleTask: ':communitymetricsPreCommit',
+    triggerPathPatterns: ['^.test-infra/metrics/.*$']
+)
+builder.build()
+

.test-infra/metrics/build.gradle

+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+apply plugin: "base"
+
+task testMetricsStack {
+  doLast {
+    // TODO(BEAM-5837): Add some actual validation of the metrics stack
+    println "Hello world!"
+  }
+}
+
+task preCommit {
+  dependsOn testMetricsStack
+}
+

build.gradle

@@ -247,6 +247,10 @@ task websitePreCommit() {
   dependsOn ":beam-website:preCommit"
 }
 
+task communityMetricsPreCommit() {
+  dependsOn ":rat"
+  dependsOn ":beam-test-infra-metrics:preCommit"
+}
 
 task runBeamDependencyCheck() {
   dependsOn ":dependencyUpdates"

settings.gradle

@@ -190,3 +190,5 @@ include "beam-runners-google-cloud-dataflow-java-fn-api-worker"
 project(":beam-runners-google-cloud-dataflow-java-fn-api-worker").dir = file("runners/google-cloud-dataflow-java/worker")
 include "beam-runners-google-cloud-dataflow-java-windmill"
 project(":beam-runners-google-cloud-dataflow-java-windmill").dir = file("runners/google-cloud-dataflow-java/worker/windmill")
+include "beam-test-infra-metrics"
+project(":beam-test-infra-metrics").dir = file(".test-infra/metrics")