Add tool to check if other requests are still running

This is needed for the Lock.java enhancement where a lock will be implicitly
released if the request owning it dies.

No matter which solution we want for refactoring the Lock itself, we will need this class.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=167600314

java/google/registry/monitoring/whitebox/WhiteboxModule.java

@@ -20,7 +20,6 @@ import static google.registry.request.RequestParameters.extractRequiredParameter
 
 import com.google.api.services.bigquery.model.TableFieldSchema;
 import com.google.appengine.api.taskqueue.Queue;
-import com.google.apphosting.api.ApiProxy;
 import com.google.common.base.Supplier;
 import com.google.common.collect.ImmutableList;
 import dagger.Module;
@@ -28,6 +27,7 @@ import dagger.Provides;
 import dagger.multibindings.IntoMap;
 import dagger.multibindings.StringKey;
 import google.registry.request.Parameter;
+import google.registry.request.RequestLogId;
 import google.registry.util.Clock;
 import java.util.UUID;
 import javax.inject.Named;
@@ -39,8 +39,6 @@ import javax.servlet.http.HttpServletRequest;
 @Module
 public class WhiteboxModule {
 
-  private static final String REQUEST_LOG_ID = "com.google.appengine.runtime.request_log_id";
-
   @Provides
   @IntoMap
   @StringKey(EppMetric.TABLE_ID)
@@ -71,16 +69,10 @@ public class WhiteboxModule {
     };
   }
 
-  @Provides
-  @Named("requestLogId")
-  static String provideRequestLogId() {
-    return ApiProxy.getCurrentEnvironment().getAttributes().get(REQUEST_LOG_ID).toString();
-  }
-
   /** Provides an EppMetric builder with the request ID and startTimestamp already initialized. */
   @Provides
   static EppMetric.Builder provideEppMetricBuilder(
-      @Named("requestLogId") String requestLogId, Clock clock) {
+      @RequestLogId String requestLogId, Clock clock) {
     return EppMetric.builderForRequest(requestLogId, clock);
   }
 

java/google/registry/request/RequestLogId.java

@@ -0,0 +1,31 @@
+// Copyright 2017 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.request;
+
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import javax.inject.Qualifier;
+
+/**
+ * Dagger qualifier for the AppEngine request_log_id.
+ *
+ * <p>This is the unique log identifier of the current request.
+ */
+@Retention(RUNTIME)
+@Qualifier
+@Documented
+public @interface RequestLogId {}

java/google/registry/request/RequestModule.java

@@ -29,6 +29,8 @@ import google.registry.request.HttpException.UnsupportedMediaTypeException;
 import google.registry.request.auth.AuthResult;
 import google.registry.request.lock.LockHandler;
 import google.registry.request.lock.LockHandlerPassthrough;
+import google.registry.util.RequestStatusChecker;
+import google.registry.util.RequestStatusCheckerImpl;
 import java.io.IOException;
 import java.util.Map;
 import javax.servlet.http.HttpServletRequest;
@@ -129,6 +131,18 @@ public final class RequestModule {
     return lockHandler;
   }
 
+  @Provides
+  static RequestStatusChecker provideRequestStatusChecker(
+      RequestStatusCheckerImpl requestStatusChecker) {
+    return requestStatusChecker;
+  }
+
+  @Provides
+  @RequestLogId
+  static String provideRequestLogId(RequestStatusChecker requestStatusChecker) {
+    return requestStatusChecker.getLogId();
+  }
+
   @Provides
   @JsonPayload
   @SuppressWarnings("unchecked")

java/google/registry/util/RequestStatusChecker.java

@@ -0,0 +1,34 @@
+// Copyright 2017 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.util;
+
+import java.io.Serializable;
+
+/** Used to query whether requests are still running. */
+public interface RequestStatusChecker extends Serializable {
+
+  /**
+   * Returns the unique log identifier of the current request.
+   *
+   * <p>Multiple calls must return the same value during the same Request.
+   */
+  public String getLogId();
+
+  /**
+   * Returns true if the given request is currently running.
+   */
+  public boolean isRunning(String requestLogId);
+}
+

java/google/registry/util/RequestStatusCheckerImpl.java

@@ -0,0 +1,83 @@
+// Copyright 2017 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.util;
+
+import com.google.appengine.api.log.LogQuery;
+import com.google.appengine.api.log.LogService;
+import com.google.appengine.api.log.LogServiceFactory;
+import com.google.appengine.api.log.RequestLogs;
+import com.google.apphosting.api.ApiProxy;
+import com.google.apphosting.api.ApiProxy.Environment;
+import com.google.common.collect.Iterables;
+import java.util.Collections;
+import javax.inject.Inject;
+
+/** Implementation of the {@link RequestStatusChecker} interface. */
+public class RequestStatusCheckerImpl implements RequestStatusChecker {
+
+  private static final long serialVersionUID = -8161977032130865437L;
+
+  private static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();
+
+  /**
+   * The key to {@link Environment#getAttributes}'s request_log_id value.
+   */
+  private static final String REQUEST_LOG_ID_KEY = "com.google.appengine.runtime.request_log_id";
+
+  private static final LogService LOG_SERVICE = LogServiceFactory.getLogService();
+
+  @Inject public RequestStatusCheckerImpl() {}
+
+  /**
+   * Returns the unique log identifier of the current request.
+   *
+   * <p>May be safely called multiple times, will always return the same result (within the same
+   * request).
+   *
+   * @see <a href="https://cloud.google.com/appengine/docs/standard/java/how-requests-are-handled#request-ids">appengine documentation</a>
+   */
+  @Override
+  public String getLogId() {
+    String requestLogId =
+        ApiProxy.getCurrentEnvironment().getAttributes().get(REQUEST_LOG_ID_KEY).toString();
+    logger.infofmt("Current requestLogId: %s", requestLogId);
+    return requestLogId;
+  }
+
+  /**
+   * Returns true if the given request is currently running.
+   *
+   * @see <a href="https://cloud.google.com/appengine/docs/standard/java/javadoc/com/google/appengine/api/log/LogQuery">appengine documentation</a>
+   */
+  @Override
+  public boolean isRunning(String requestLogId) {
+    RequestLogs requestLogs =
+        Iterables.getOnlyElement(
+            LOG_SERVICE.fetch(
+                LogQuery.Builder.withRequestIds(
+                    Collections.singletonList(requestLogId))),
+            null);
+    // requestLogs will be null if that requestLogId isn't found at all, which also implies it's not
+    // running.
+    if (requestLogs == null) {
+      logger.infofmt(
+          "Queried an unrecognized requestLogId %s - assume it isn't running", requestLogId);
+      return false;
+    }
+    logger.infofmt(
+        "Found logs for requestLogId %s - isFinished: %s", requestLogId, requestLogs.isFinished());
+    return !requestLogs.isFinished();
+  }
+}