Java tutorial
// 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.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))); } }