RestApiServlet: Handle RequestCancelledException for REST calls
Catch RequestCancelledException in RestApiServlet and return proper
HTTP response codes.
RequestCancelledException is not being thrown yet, this is a preparation
to handle it correctly when we start detecting cancelled requests later
and aborting them by throwing this exception.
If a request is cancelled we return '499 Client Closed Request'. This is
a non-standard status code that was introduced by nginx for the case
when a client closes the connection [1].
If a request is cancelled due to an exceeded deadline we return '408
Client Provided Deadline Exceeded' or '408 Server Deadline Exceeded'.
408 is a standard response code that is returned when a request timed
out [2].
[1] https://httpstatuses.com/499
[2] https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/408
Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: Ice6d35a04c68e850307fc36d0ef71c5d3a15ecb9
diff --git a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
index 39db61d..b04ae96 100644
--- a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
+++ b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
@@ -46,6 +46,7 @@
import static javax.servlet.http.HttpServletResponse.SC_NOT_MODIFIED;
import static javax.servlet.http.HttpServletResponse.SC_OK;
import static javax.servlet.http.HttpServletResponse.SC_PRECONDITION_FAILED;
+import static javax.servlet.http.HttpServletResponse.SC_REQUEST_TIMEOUT;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Joiner;
@@ -112,6 +113,7 @@
import com.google.gerrit.server.RequestListener;
import com.google.gerrit.server.audit.ExtendedHttpAuditEvent;
import com.google.gerrit.server.cache.PerThreadCache;
+import com.google.gerrit.server.cancellation.RequestCancelledException;
import com.google.gerrit.server.change.ChangeFinder;
import com.google.gerrit.server.change.RevisionResource;
import com.google.gerrit.server.config.GerritServerConfig;
@@ -190,6 +192,7 @@
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
+import org.apache.commons.lang.WordUtils;
import org.eclipse.jgit.http.server.ServletUtils;
import org.eclipse.jgit.lib.Config;
import org.eclipse.jgit.util.TemporaryBuffer;
@@ -225,6 +228,7 @@
public static final String XD_METHOD = "$m";
public static final int SC_UNPROCESSABLE_ENTITY = 422;
public static final int SC_TOO_MANY_REQUESTS = 429;
+ public static final int SC_CLIENT_CLOSED_REQUEST = 499;
private static final int HEAP_EST_SIZE = 10 * 8 * 1024; // Presize 10 blocks.
private static final String PLAIN_TEXT = "text/plain";
@@ -709,6 +713,27 @@
messageOr(e, "Quota limit reached"),
e.caching(),
e);
+ } catch (RequestCancelledException e) {
+ cause = Optional.of(e);
+ switch (e.getCancellationReason()) {
+ case CLIENT_CLOSED_REQUEST:
+ statusCode = SC_CLIENT_CLOSED_REQUEST;
+ break;
+ case CLIENT_PROVIDED_DEADLINE_EXCEEDED:
+ case SERVER_DEADLINE_EXCEEDED:
+ statusCode = SC_REQUEST_TIMEOUT;
+ break;
+ }
+
+ StringBuilder msg =
+ new StringBuilder(
+ WordUtils.capitalizeFully(e.getCancellationReason().name().replaceAll("_", " ")));
+ if (e.getCancellationMessage().isPresent()) {
+ msg.append("\n\n");
+ msg.append(e.getCancellationMessage().get());
+ }
+
+ responseBytes = replyError(req, res, statusCode, msg.toString(), e);
} catch (Exception e) {
cause = Optional.of(e);
statusCode = SC_INTERNAL_SERVER_ERROR;
diff --git a/javatests/com/google/gerrit/acceptance/rest/CancellationIT.java b/javatests/com/google/gerrit/acceptance/rest/CancellationIT.java
new file mode 100644
index 0000000..1de6438
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/rest/CancellationIT.java
@@ -0,0 +1,116 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// 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 com.google.gerrit.acceptance.rest;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.httpd.restapi.RestApiServlet.SC_CLIENT_CLOSED_REQUEST;
+import static org.apache.http.HttpStatus.SC_REQUEST_TIMEOUT;
+
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.ExtensionRegistry;
+import com.google.gerrit.acceptance.ExtensionRegistry.Registration;
+import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.server.cancellation.RequestCancelledException;
+import com.google.gerrit.server.cancellation.RequestStateProvider;
+import com.google.gerrit.server.project.CreateProjectArgs;
+import com.google.gerrit.server.validators.ProjectCreationValidationListener;
+import com.google.gerrit.server.validators.ValidationException;
+import com.google.inject.Inject;
+import org.junit.Test;
+
+public class CancellationIT extends AbstractDaemonTest {
+ @Inject private ExtensionRegistry extensionRegistry;
+
+ @Test
+ public void handleClientDisconnected() throws Exception {
+ ProjectCreationValidationListener projectCreationListener =
+ new ProjectCreationValidationListener() {
+ @Override
+ public void validateNewProject(CreateProjectArgs args) throws ValidationException {
+ // Simulate a request cancellation by throwing RequestCancelledException. In contrast to
+ // an actual request cancellation this allows us to verify the HTTP status code that is
+ // set when a request is cancelled.
+ throw new RequestCancelledException(
+ RequestStateProvider.Reason.CLIENT_CLOSED_REQUEST, /* cancellationMessage= */ null);
+ }
+ };
+ try (Registration registration =
+ extensionRegistry.newRegistration().add(projectCreationListener)) {
+ RestResponse response = adminRestSession.put("/projects/" + name("new"));
+ assertThat(response.getStatusCode()).isEqualTo(SC_CLIENT_CLOSED_REQUEST);
+ assertThat(response.getEntityContent()).isEqualTo("Client Closed Request");
+ }
+ }
+
+ @Test
+ public void handleClientDeadlineExceeded() throws Exception {
+ ProjectCreationValidationListener projectCreationListener =
+ new ProjectCreationValidationListener() {
+ @Override
+ public void validateNewProject(CreateProjectArgs args) throws ValidationException {
+ // Simulate an exceeded deadline by throwing RequestCancelledException.
+ throw new RequestCancelledException(
+ RequestStateProvider.Reason.CLIENT_PROVIDED_DEADLINE_EXCEEDED,
+ /* cancellationMessage= */ null);
+ }
+ };
+ try (Registration registration =
+ extensionRegistry.newRegistration().add(projectCreationListener)) {
+ RestResponse response = adminRestSession.put("/projects/" + name("new"));
+ assertThat(response.getStatusCode()).isEqualTo(SC_REQUEST_TIMEOUT);
+ assertThat(response.getEntityContent()).isEqualTo("Client Provided Deadline Exceeded");
+ }
+ }
+
+ @Test
+ public void handleServerDeadlineExceeded() throws Exception {
+ ProjectCreationValidationListener projectCreationListener =
+ new ProjectCreationValidationListener() {
+ @Override
+ public void validateNewProject(CreateProjectArgs args) throws ValidationException {
+ // Simulate an exceeded deadline by throwing RequestCancelledException.
+ throw new RequestCancelledException(
+ RequestStateProvider.Reason.SERVER_DEADLINE_EXCEEDED,
+ /* cancellationMessage= */ null);
+ }
+ };
+ try (Registration registration =
+ extensionRegistry.newRegistration().add(projectCreationListener)) {
+ RestResponse response = adminRestSession.put("/projects/" + name("new"));
+ assertThat(response.getStatusCode()).isEqualTo(SC_REQUEST_TIMEOUT);
+ assertThat(response.getEntityContent()).isEqualTo("Server Deadline Exceeded");
+ }
+ }
+
+ @Test
+ public void handleRequestCancellationWithMessage() throws Exception {
+ ProjectCreationValidationListener projectCreationListener =
+ new ProjectCreationValidationListener() {
+ @Override
+ public void validateNewProject(CreateProjectArgs args) throws ValidationException {
+ // Simulate an exceeded deadline by throwing RequestCancelledException.
+ throw new RequestCancelledException(
+ RequestStateProvider.Reason.SERVER_DEADLINE_EXCEEDED, "deadline = 10m");
+ }
+ };
+ try (Registration registration =
+ extensionRegistry.newRegistration().add(projectCreationListener)) {
+ RestResponse response = adminRestSession.put("/projects/" + name("new"));
+ assertThat(response.getStatusCode()).isEqualTo(SC_REQUEST_TIMEOUT);
+ assertThat(response.getEntityContent())
+ .isEqualTo("Server Deadline Exceeded\n\ndeadline = 10m");
+ }
+ }
+}
