Daggerize ExportSnapshotServlet and CheckSnapshotServlet

Eradicate the last remnants of un-injectable servlets!

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=145598002

java/google/registry/export/CheckSnapshotAction.java

@@ -0,0 +1,162 @@
+// Copyright 2016 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.export;
+
+import static com.google.common.collect.Sets.intersection;
+import static google.registry.export.LoadSnapshotAction.enqueueLoadSnapshotTask;
+import static google.registry.request.Action.Method.GET;
+import static google.registry.request.Action.Method.POST;
+import static google.registry.util.FormattingLogger.getLoggerForCallerClass;
+
+import com.google.appengine.api.taskqueue.QueueFactory;
+import com.google.appengine.api.taskqueue.TaskHandle;
+import com.google.appengine.api.taskqueue.TaskOptions;
+import com.google.appengine.api.taskqueue.TaskOptions.Method;
+import com.google.common.base.Joiner;
+import com.google.common.base.Splitter;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+import google.registry.export.DatastoreBackupInfo.BackupStatus;
+import google.registry.request.Action;
+import google.registry.request.HttpException.BadRequestException;
+import google.registry.request.HttpException.NoContentException;
+import google.registry.request.HttpException.NotModifiedException;
+import google.registry.request.Parameter;
+import google.registry.request.RequestMethod;
+import google.registry.request.Response;
+import google.registry.util.FormattingLogger;
+import java.util.Set;
+import javax.inject.Inject;
+import org.joda.time.Duration;
+import org.joda.time.PeriodType;
+import org.joda.time.format.PeriodFormat;
+
+/**
+ * Action that checks the status of a snapshot, and if complete, trigger loading it into BigQuery.
+ */
+@Action(
+  path = CheckSnapshotAction.PATH,
+  method = {POST, GET},
+  automaticallyPrintOk = true
+)
+public class CheckSnapshotAction implements Runnable {
+
+  /** Parameter names for passing parameters into this action. */
+  static final String CHECK_SNAPSHOT_NAME_PARAM = "name";
+
+  static final String CHECK_SNAPSHOT_KINDS_TO_LOAD_PARAM = "kindsToLoad";
+
+  /** Action-specific details needed for enqueuing tasks against itself. */
+  static final String QUEUE = "export-snapshot-poll"; // See queue.xml.
+
+  static final String PATH = "/_dr/task/checkSnapshot"; // See web.xml.
+  static final Duration POLL_COUNTDOWN = Duration.standardMinutes(2);
+
+  /** The maximum amount of time we allow a backup to run before abandoning it. */
+  static final Duration MAXIMUM_BACKUP_RUNNING_TIME = Duration.standardHours(20);
+
+  private static final FormattingLogger logger = getLoggerForCallerClass();
+
+  @Inject Response response;
+  @Inject @RequestMethod Action.Method requestMethod;
+  @Inject DatastoreBackupService backupService;
+  @Inject @Parameter(CHECK_SNAPSHOT_NAME_PARAM) String snapshotName;
+  @Inject @Parameter(CHECK_SNAPSHOT_KINDS_TO_LOAD_PARAM) String kindsToLoadParam;
+  @Inject CheckSnapshotAction() {}
+
+  @Override
+  public void run() {
+    if (requestMethod == POST) {
+      checkAndLoadSnapshotIfComplete();
+    } else {
+      // This is a GET request.
+      response.setPayload(getBackup().getInformation());
+    }
+  }
+
+  private DatastoreBackupInfo getBackup() {
+    try {
+      return backupService.findByName(snapshotName);
+    } catch (IllegalArgumentException e) {
+      String message = String.format("Bad backup name %s: %s", snapshotName, e.getMessage());
+      // TODO(b/19081569): Ideally this would return a 2XX error so the task would not be
+      // retried but we might abandon backups that start late and haven't yet written to
+      // datastore. We could fix that by replacing this with a two-phase polling strategy.
+      throw new BadRequestException(message, e);
+    }
+  }
+
+  private void checkAndLoadSnapshotIfComplete() {
+    Set<String> kindsToLoad = ImmutableSet.copyOf(Splitter.on(',').split(kindsToLoadParam));
+    DatastoreBackupInfo backup = getBackup();
+    // Stop now if the backup is not complete.
+    if (!backup.getStatus().equals(BackupStatus.COMPLETE)) {
+      Duration runningTime = backup.getRunningTime();
+      if (runningTime.isShorterThan(MAXIMUM_BACKUP_RUNNING_TIME)) {
+        // Backup might still be running, so send a 304 to have the task retry.
+        throw new NotModifiedException(
+            String.format("Datastore backup %s still pending", snapshotName));
+      } else {
+        // Declare the backup a lost cause, and send 204 No Content so the task will
+        // not be retried.
+        String message =
+            String.format(
+                "Datastore backup %s abandoned - not complete after %s",
+                snapshotName,
+                PeriodFormat.getDefault()
+                    .print(
+                        runningTime
+                            .toPeriod()
+                            .normalizedStandard(PeriodType.dayTime().withMillisRemoved())));
+        throw new NoContentException(message);
+      }
+    }
+    // Get a compact string to identify this snapshot in BigQuery by trying to parse the unique
+    // suffix out of the snapshot name and falling back to the start time as a string.
+    String snapshotId =
+        snapshotName.startsWith(ExportSnapshotAction.SNAPSHOT_PREFIX)
+            ? snapshotName.substring(ExportSnapshotAction.SNAPSHOT_PREFIX.length())
+            : backup.getStartTime().toString("YYYYMMdd_HHmmss");
+    // Log a warning if kindsToLoad is not a subset of the exported snapshot kinds.
+    if (!backup.getKinds().containsAll(kindsToLoad)) {
+      logger.warningfmt(
+          "Kinds to load included non-exported kinds: %s",
+          Sets.difference(kindsToLoad, backup.getKinds()));
+    }
+    // Load kinds from the snapshot, limited to those also in kindsToLoad (if it's present).
+    ImmutableSet<String> exportedKindsToLoad =
+        ImmutableSet.copyOf(intersection(backup.getKinds(), kindsToLoad));
+    String message = String.format("Datastore backup %s complete - ", snapshotName);
+    if (exportedKindsToLoad.isEmpty()) {
+      message += "no kinds to load into BigQuery";
+    } else {
+      enqueueLoadSnapshotTask(snapshotId, backup.getGcsFilename().get(), exportedKindsToLoad);
+      message += "BigQuery load task enqueued";
+    }
+    logger.info(message);
+    response.setPayload(message);
+  }
+
+  /** Enqueue a poll task to monitor the named snapshot for completion. */
+  static TaskHandle enqueuePollTask(String snapshotName, ImmutableSet<String> kindsToLoad) {
+    return QueueFactory.getQueue(QUEUE)
+        .add(
+            TaskOptions.Builder.withUrl(PATH)
+                .method(Method.POST)
+                .countdownMillis(POLL_COUNTDOWN.getMillis())
+                .param(CHECK_SNAPSHOT_NAME_PARAM, snapshotName)
+                .param(CHECK_SNAPSHOT_KINDS_TO_LOAD_PARAM, Joiner.on(',').join(kindsToLoad)));
+  }
+}