Wire in MetricReporter into the backend servlet to publish metrics

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=130468842

java/google/registry/monitoring/whitebox/StackdriverModule.java

@@ -19,11 +19,20 @@ import com.google.api.client.http.HttpTransport;
 import com.google.api.client.json.JsonFactory;
 import com.google.api.services.monitoring.v3.Monitoring;
 import com.google.api.services.monitoring.v3.MonitoringScopes;
+import com.google.api.services.monitoring.v3.model.MonitoredResource;
+import com.google.appengine.api.ThreadManager;
+import com.google.appengine.api.modules.ModulesService;
+import com.google.appengine.repackaged.com.google.common.collect.ImmutableMap;
 import com.google.common.base.Function;
 import dagger.Module;
 import dagger.Provides;
 import google.registry.config.ConfigModule.Config;
+import google.registry.monitoring.metrics.MetricWriter;
+import google.registry.monitoring.metrics.StackdriverWriter;
 import java.util.Set;
+import java.util.concurrent.ThreadFactory;
+import javax.inject.Named;
+import org.joda.time.Duration;
 
 /** Dagger module for Google Stackdriver service connection objects. */
 @Module
@@ -39,4 +48,43 @@ public final class StackdriverModule {
         .setApplicationName(projectId)
         .build();
   }
+
+  @Provides
+  static MetricWriter provideMetricWriter(
+      Monitoring monitoringClient,
+      @Config("projectId") String projectId,
+      ModulesService modulesService,
+      @Config("stackdriverMaxQps") int maxQps,
+      @Config("stackdriverMaxPointsPerRequest") int maxPointsPerRequest) {
+    // The MonitoredResource for GAE apps lacks an instance_id field, so we encode it into the
+    // version_id field so that metrics from different instances don't interleave.
+    return new StackdriverWriter(
+        monitoringClient,
+        projectId,
+        new MonitoredResource()
+            .setType("gae_app")
+            .setLabels(
+                ImmutableMap.of(
+                    "module_id",
+                    modulesService.getCurrentModule(),
+                    "version_id",
+                    modulesService.getCurrentVersion()
+                        + ":"
+                        + modulesService.getCurrentInstanceId())),
+        maxQps,
+        maxPointsPerRequest);
+  }
+
+  @Provides
+  @Named("metricsBackgroundThreadFactory")
+  static ThreadFactory provideThreadFactory() {
+    return ThreadManager.backgroundThreadFactory();
+  }
+
+  @Provides
+  @Named("metricsWriteInterval")
+  static long provideMetricsWriteInterval(
+      @Config("metricsWriteInterval") Duration metricsWriteInterval) {
+    return metricsWriteInterval.getStandardSeconds();
+  }
 }