Reduce duplicate code in the servlets

Currently, all 4 servlets (backend, frontend, pubapi, tools) have duplicates of
the same exact code.

That's an anti-pattern!

Created a ServletBase they can all extend which has the duplicate code.

As a bonus, the tools servlet now runs the metric reporter, meaning tool
related metrics will now be reported!

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=219792176

java/google/registry/module/backend/BUILD

@@ -27,6 +27,7 @@ java_library(
         "//java/google/registry/keyring/kms",
         "//java/google/registry/mapreduce",
         "//java/google/registry/model",
+        "//java/google/registry/module",
         "//java/google/registry/monitoring/whitebox",
         "//java/google/registry/rde",
         "//java/google/registry/rde/imports",

java/google/registry/module/backend/BackendServlet.java

@@ -14,66 +14,18 @@
 
 package google.registry.module.backend;
 
-import com.google.appengine.api.LifecycleManager;
-import com.google.common.flogger.FluentLogger;
 import com.google.monitoring.metrics.MetricReporter;
 import dagger.Lazy;
-import google.registry.util.SystemClock;
+import google.registry.module.ServletBase;
-import java.io.IOException;
-import java.security.Security;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
-import javax.servlet.http.HttpServlet;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-import org.bouncycastle.jce.provider.BouncyCastleProvider;
-import org.joda.time.DateTime;
 
 /** Servlet that should handle all requests to our "backend" App Engine module. */
-public final class BackendServlet extends HttpServlet {
+public final class BackendServlet extends ServletBase {
 
   private static final BackendComponent component = DaggerBackendComponent.create();
   private static final BackendRequestHandler requestHandler = component.requestHandler();
   private static final Lazy<MetricReporter> metricReporter = component.metricReporter();
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-  private static final SystemClock clock = new SystemClock();
 
-  @Override
+  public BackendServlet() {
-  public void init() {
+    super(requestHandler, metricReporter);
-    Security.addProvider(new BouncyCastleProvider());
-
-    // If metric reporter failed to instantiate for any reason (bad keyring, bad json credential,
-    // etc), we log the error but keep the main thread running. Also the shutdown hook will only be
-    // registered if metric reporter starts up correctly.
-    try {
-      metricReporter.get().startAsync().awaitRunning(10, TimeUnit.SECONDS);
-      logger.atInfo().log("Started up MetricReporter");
-      LifecycleManager.getInstance()
-          .setShutdownHook(
-              () -> {
-                try {
-                  metricReporter.get().stopAsync().awaitTerminated(10, TimeUnit.SECONDS);
-                  logger.atInfo().log("Shut down MetricReporter");
-                } catch (TimeoutException timeoutException) {
-                  logger.atSevere().withCause(timeoutException).log(
-                      "Failed to stop MetricReporter: %s", timeoutException);
-                }
-              });
-    } catch (Exception e) {
-      logger.atSevere().withCause(e).log("Failed to initialize MetricReporter.");
-    }
-  }
-
-  @Override
-  public void service(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
-    logger.atInfo().log("Received backend request");
-    DateTime startTime = clock.nowUtc();
-    try {
-      requestHandler.handleRequest(req, rsp);
-    } finally {
-      logger.atInfo().log(
-          "Finished backend request. Latency: %.3fs",
-          (clock.nowUtc().getMillis() - startTime.getMillis()) / 1000d);
-    }
   }
 }

java/google/registry/module/frontend/BUILD

@@ -14,6 +14,7 @@ java_library(
         "//java/google/registry/keyring",
         "//java/google/registry/keyring/api",
         "//java/google/registry/keyring/kms",
+        "//java/google/registry/module",
         "//java/google/registry/monitoring/whitebox",
         "//java/google/registry/request",
         "//java/google/registry/request:modules",

java/google/registry/module/frontend/FrontendServlet.java

@@ -14,65 +14,18 @@
 
 package google.registry.module.frontend;
 
-import com.google.appengine.api.LifecycleManager;
-import com.google.common.flogger.FluentLogger;
 import com.google.monitoring.metrics.MetricReporter;
 import dagger.Lazy;
-import google.registry.util.SystemClock;
+import google.registry.module.ServletBase;
-import java.io.IOException;
-import java.security.Security;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
-import javax.servlet.http.HttpServlet;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-import org.bouncycastle.jce.provider.BouncyCastleProvider;
-import org.joda.time.DateTime;
 
 /** Servlet that should handle all requests to our "default" App Engine module. */
-public final class FrontendServlet extends HttpServlet {
+public final class FrontendServlet extends ServletBase {
 
   private static final FrontendComponent component = DaggerFrontendComponent.create();
   private static final FrontendRequestHandler requestHandler = component.requestHandler();
   private static final Lazy<MetricReporter> metricReporter = component.metricReporter();
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-  private static final SystemClock clock = new SystemClock();
 
-  @Override
+  public FrontendServlet() {
-  public void init() {
+    super(requestHandler, metricReporter);
-    Security.addProvider(new BouncyCastleProvider());
-
-    // If metric reporter failed to instantiate for any reason (bad keyring, bad json credential,
-    // etc), we log the error but keep the main thread running. Also the shutdown hook will only be
-    // registered if metric reporter starts up correctly.
-    try {
-      metricReporter.get().startAsync().awaitRunning(10, TimeUnit.SECONDS);
-      logger.atInfo().log("Started up MetricReporter");
-      LifecycleManager.getInstance()
-          .setShutdownHook(
-              () -> {
-                try {
-                  metricReporter.get().stopAsync().awaitTerminated(10, TimeUnit.SECONDS);
-                  logger.atInfo().log("Shut down MetricReporter");
-                } catch (TimeoutException e) {
-                  logger.atSevere().withCause(e).log("Failed to stop MetricReporter.");
-                }
-              });
-    } catch (Exception e) {
-      logger.atSevere().withCause(e).log("Failed to initialize MetricReporter.");
-    }
-  }
-
-  @Override
-  public void service(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
-    logger.atInfo().log("Received frontend request");
-    DateTime startTime = clock.nowUtc();
-    try {
-      requestHandler.handleRequest(req, rsp);
-    } finally {
-      logger.atInfo().log(
-          "Finished frontend request. Latency: %.3fs",
-          (clock.nowUtc().getMillis() - startTime.getMillis()) / 1000d);
-    }
   }
 }

java/google/registry/module/pubapi/BUILD

@@ -14,6 +14,7 @@ java_library(
         "//java/google/registry/keyring",
         "//java/google/registry/keyring/api",
         "//java/google/registry/keyring/kms",
+        "//java/google/registry/module",
         "//java/google/registry/monitoring/whitebox",
         "//java/google/registry/rdap",
         "//java/google/registry/request",

java/google/registry/module/pubapi/PubApiComponent.java

@@ -47,12 +47,12 @@ import javax.inject.Singleton;
       CredentialModule.class,
       CustomLogicFactoryModule.class,
       DummyKeyringModule.class,
-      PubApiRequestComponentModule.class,
       Jackson2Module.class,
       KeyModule.class,
       KeyringModule.class,
       KmsModule.class,
       NetHttpTransportModule.class,
+      PubApiRequestComponentModule.class,
       ServerTridProviderModule.class,
       StackdriverModule.class,
       SystemClockModule.class,

java/google/registry/module/pubapi/PubApiServlet.java

@@ -14,65 +14,18 @@
 
 package google.registry.module.pubapi;
 
-import com.google.appengine.api.LifecycleManager;
-import com.google.common.flogger.FluentLogger;
 import com.google.monitoring.metrics.MetricReporter;
 import dagger.Lazy;
-import google.registry.util.SystemClock;
+import google.registry.module.ServletBase;
-import java.io.IOException;
-import java.security.Security;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
-import javax.servlet.http.HttpServlet;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-import org.bouncycastle.jce.provider.BouncyCastleProvider;
-import org.joda.time.DateTime;
 
 /** Servlet that should handle all requests to our "default" App Engine module. */
-public final class PubApiServlet extends HttpServlet {
+public final class PubApiServlet extends ServletBase {
 
   private static final PubApiComponent component = DaggerPubApiComponent.create();
   private static final PubApiRequestHandler requestHandler = component.requestHandler();
   private static final Lazy<MetricReporter> metricReporter = component.metricReporter();
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-  private static final SystemClock clock = new SystemClock();
 
-  @Override
+  public PubApiServlet() {
-  public void init() {
+    super(requestHandler, metricReporter);
-    Security.addProvider(new BouncyCastleProvider());
-
-    // If metric reporter failed to instantiate for any reason (bad keyring, bad json credential,
-    // etc), we log the error but keep the main thread running. Also the shutdown hook will only be
-    // registered if metric reporter starts up correctly.
-    try {
-      metricReporter.get().startAsync().awaitRunning(10, TimeUnit.SECONDS);
-      logger.atInfo().log("Started up MetricReporter");
-      LifecycleManager.getInstance()
-          .setShutdownHook(
-              () -> {
-                try {
-                  metricReporter.get().stopAsync().awaitTerminated(10, TimeUnit.SECONDS);
-                  logger.atInfo().log("Shut down MetricReporter");
-                } catch (TimeoutException e) {
-                  logger.atSevere().withCause(e).log("Failed to stop MetricReporter.");
-                }
-              });
-    } catch (Exception e) {
-      logger.atSevere().withCause(e).log("Failed to initialize MetricReporter.");
-    }
-  }
-
-  @Override
-  public void service(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
-    logger.atInfo().log("Received pubapi request");
-    DateTime startTime = clock.nowUtc();
-    try {
-      requestHandler.handleRequest(req, rsp);
-    } finally {
-      logger.atInfo().log(
-          "Finished pubapi request. Latency: %.3fs",
-          (clock.nowUtc().getMillis() - startTime.getMillis()) / 1000d);
-    }
   }
 }

java/google/registry/module/tools/BUILD

@@ -20,6 +20,7 @@ java_library(
         "//java/google/registry/keyring/kms",
         "//java/google/registry/loadtest",
         "//java/google/registry/mapreduce",
+        "//java/google/registry/module",
         "//java/google/registry/monitoring/whitebox",
         "//java/google/registry/request",
         "//java/google/registry/request:modules",
@@ -30,6 +31,7 @@ java_library(
         "@com_google_dagger",
         "@com_google_flogger",
         "@com_google_flogger_system_backend",
+        "@com_google_monitoring_client_metrics",
         "@javax_inject",
         "@javax_servlet_api",
         "@joda_time",

java/google/registry/module/tools/ToolsComponent.java

@@ -14,7 +14,9 @@
 
 package google.registry.module.tools;
 
+import com.google.monitoring.metrics.MetricReporter;
 import dagger.Component;
+import dagger.Lazy;
 import google.registry.config.CredentialModule;
 import google.registry.config.RegistryConfig.ConfigModule;
 import google.registry.export.DriveModule;
@@ -29,6 +31,7 @@ import google.registry.keyring.api.DummyKeyringModule;
 import google.registry.keyring.api.KeyModule;
 import google.registry.keyring.kms.KmsModule;
 import google.registry.module.tools.ToolsRequestComponent.ToolsRequestComponentModule;
+import google.registry.monitoring.whitebox.StackdriverModule;
 import google.registry.request.Modules.DatastoreServiceModule;
 import google.registry.request.Modules.Jackson2Module;
 import google.registry.request.Modules.NetHttpTransportModule;
@@ -62,6 +65,7 @@ import javax.inject.Singleton;
       KmsModule.class,
       NetHttpTransportModule.class,
       ServerTridProviderModule.class,
+      StackdriverModule.class,
       SystemClockModule.class,
       SystemSleeperModule.class,
       ToolsRequestComponentModule.class,
@@ -70,4 +74,6 @@ import javax.inject.Singleton;
     })
 interface ToolsComponent {
   ToolsRequestHandler requestHandler();
+
+  Lazy<MetricReporter> metricReporter();
 }

java/google/registry/module/tools/ToolsServlet.java

@@ -14,39 +14,18 @@
 
 package google.registry.module.tools;
 
-import com.google.common.flogger.FluentLogger;
+import com.google.monitoring.metrics.MetricReporter;
-import google.registry.util.SystemClock;
+import dagger.Lazy;
-import java.io.IOException;
+import google.registry.module.ServletBase;
-import java.security.Security;
-import javax.servlet.http.HttpServlet;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-import org.bouncycastle.jce.provider.BouncyCastleProvider;
-import org.joda.time.DateTime;
 
 /** Servlet that should handle all requests to our "tools" App Engine module. */
-public final class ToolsServlet extends HttpServlet {
+public final class ToolsServlet extends ServletBase {
 
   private static final ToolsComponent component = DaggerToolsComponent.create();
   private static final ToolsRequestHandler requestHandler = component.requestHandler();
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+  private static final Lazy<MetricReporter> metricReporter = component.metricReporter();
-  private static final SystemClock clock = new SystemClock();
 
-  @Override
+  public ToolsServlet() {
-  public void init() {
+    super(requestHandler, metricReporter);
-    Security.addProvider(new BouncyCastleProvider());
-  }
-
-  @Override
-  public void service(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
-    logger.atInfo().log("Received tools request");
-    DateTime startTime = clock.nowUtc();
-    try {
-      requestHandler.handleRequest(req, rsp);
-    } finally {
-      logger.atInfo().log(
-          "Finished tools request. Latency: %.3fs",
-          (clock.nowUtc().getMillis() - startTime.getMillis()) / 1000d);
-    }
   }
 }