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Merged
merged 8 commits into from
Jan 2, 2020
Merged

Make EC2 Discovery Plugin Retry Requests #50550

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8945922
Make EC2 Discovery Plugin Retry Requests
original-brownbear Jan 2, 2020
7a5b21f
nicer
original-brownbear Jan 2, 2020
9c8c589
nicer
original-brownbear Jan 2, 2020
2d835a8
nicer
original-brownbear Jan 2, 2020
d015576
default retry backoff
original-brownbear Jan 2, 2020
ba20261
Merge remote-tracking branch 'elastic/master' into 50462
original-brownbear Jan 2, 2020
fb28d07
Merge remote-tracking branch 'elastic/master' into 50462
original-brownbear Jan 2, 2020
ec56d95
CR: comments
original-brownbear Jan 2, 2020
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4 changes: 2 additions & 2 deletions plugins/discovery-ec2/src/main/java/org/elasticsearch/discovery/ec2/AwsEc2ServiceImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,7 @@
import java.util.concurrent.atomic.AtomicReference;

class AwsEc2ServiceImpl implements AwsEc2Service {

private static final Logger logger = LogManager.getLogger(AwsEc2ServiceImpl.class);

private final AtomicReference<LazyInitializable<AmazonEc2Reference, ElasticsearchException>> lazyClientReference =
Expand Down Expand Up @@ -79,7 +79,7 @@ static ClientConfiguration buildConfiguration(Logger logger, Ec2ClientSettings c
// Increase the number of retries in case of 5xx API responses
final Random rand = Randomness.get();
final RetryPolicy retryPolicy = new RetryPolicy(
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Can we avoid setting our own retry policy at all and use the SDK default? The SDK makes a more nuanced decision about how much to back off based on the error type. If we really want 10 retries then that can be overridden with setMaxErrorRetry(10) instead?

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Right, that's much nicer. Moved to the default and kept retries at 10 for now in d015576 :)

RetryPolicy.RetryCondition.NO_RETRY_CONDITION,
null,
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Just using the default retry condition here now. We may want to make the retry interval configurable, if only internally for tests. The current settings make the first retry happen after almost 20s but I didn't want to add that complication here yet.

(originalRequest, exception, retriesAttempted) -> {
// with 10 retries the max delay time is 320s/320000ms (10 * 2^5 * 1 * 1000)
logger.warn("EC2 API request failed, retry again. Reason was:", exception);
Expand Down
259 changes: 259 additions & 0 deletions plugins/discovery-ec2/src/test/java/org/elasticsearch/discovery/ec2/EC2RetriesTests.java
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@@ -0,0 +1,259 @@
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.discovery.ec2;

import com.amazonaws.http.HttpMethodName;
import com.sun.net.httpserver.HttpServer;
import org.apache.http.HttpStatus;
import org.apache.http.NameValuePair;
import org.apache.http.client.utils.URLEncodedUtils;
import org.elasticsearch.Version;
import org.elasticsearch.common.SuppressForbidden;
import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
import org.elasticsearch.common.network.InetAddresses;
import org.elasticsearch.common.network.NetworkService;
import org.elasticsearch.common.settings.MockSecureSettings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.util.PageCacheRecycler;
import org.elasticsearch.core.internal.io.IOUtils;
import org.elasticsearch.discovery.SeedHostsProvider;
import org.elasticsearch.discovery.SeedHostsResolver;
import org.elasticsearch.indices.breaker.NoneCircuitBreakerService;
import org.elasticsearch.mocksocket.MockHttpServer;
import org.elasticsearch.test.ESTestCase;
import org.elasticsearch.test.transport.MockTransportService;
import org.elasticsearch.threadpool.TestThreadPool;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.TransportService;
import org.elasticsearch.transport.nio.MockNioTransport;
import org.hamcrest.Matchers;
import org.junit.After;
import org.junit.Before;

import javax.xml.XMLConstants;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamWriter;

import java.io.IOException;
import java.io.StringWriter;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;

import static java.nio.charset.StandardCharsets.UTF_8;
import static org.hamcrest.Matchers.hasSize;
import static org.hamcrest.Matchers.is;

@SuppressForbidden(reason = "use a http server")
public class EC2RetriesTests extends ESTestCase {
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Admittedly quite a bit of code, but I'm hoping we can just extend the REST layer mocking here and dry things up against the fixture step-by-step like we did for S3 and the other cloud providers in the repository tests to get rid of all our complicated mocking of actual AWS SDK classes and just mock on the REST layer.


private HttpServer httpServer;

private ThreadPool threadPool;

private MockTransportService transportService;

private NetworkService networkService = new NetworkService(Collections.emptyList());

@Before
public void setUp() throws Exception {
httpServer = MockHttpServer.createHttp(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
httpServer.start();
threadPool = new TestThreadPool(EC2RetriesTests.class.getName());
final MockNioTransport transport = new MockNioTransport(Settings.EMPTY, Version.CURRENT, threadPool, networkService,
PageCacheRecycler.NON_RECYCLING_INSTANCE, new NamedWriteableRegistry(Collections.emptyList()),
new NoneCircuitBreakerService());
transportService =
new MockTransportService(Settings.EMPTY, transport, threadPool, TransportService.NOOP_TRANSPORT_INTERCEPTOR, null);
super.setUp();
}

@After
public void tearDown() throws Exception {
try {
IOUtils.close(transportService, () -> terminate(threadPool), () -> httpServer.stop(0));
} finally {
super.tearDown();
}
}

public void testEC2DiscoveryRetriesOnRateLimiting() throws IOException {
final String accessKey = "ec2_access";
final List<String> hosts = List.of("127.0.0.1:9000");
final Set<String> failedRequests = Collections.newSetFromMap(new ConcurrentHashMap<>());
httpServer.createContext("/", exchange -> {
if (exchange.getRequestMethod().equals(HttpMethodName.POST.name())) {
final String request = new String(exchange.getRequestBody().readAllBytes(), UTF_8);
final String userAgent = exchange.getRequestHeaders().getFirst("User-Agent");
if (userAgent != null && userAgent.startsWith("aws-sdk-java")) {
final String auth = exchange.getRequestHeaders().getFirst("Authorization");
if (auth == null || auth.contains(accessKey) == false) {
throw new IllegalArgumentException("wrong access key: " + auth);
}
if (failedRequests.add(exchange.getRequestHeaders().getFirst("Amz-sdk-invocation-id"))) {
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Could we also check that we retry repeatedly? The first five retries take less than a second.

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Done :)

exchange.sendResponseHeaders(HttpStatus.SC_SERVICE_UNAVAILABLE, -1);
return;
}
// Simulate an EC2 DescribeInstancesResponse
byte[] responseBody = null;
for (NameValuePair parse : URLEncodedUtils.parse(request, UTF_8)) {
if ("Action".equals(parse.getName())) {
responseBody = generateDescribeInstancesResponse(hosts);
break;
}
}
responseBody = responseBody == null ? new byte[0] : responseBody;
exchange.getResponseHeaders().set("Content-Type", "text/xml; charset=UTF-8");
exchange.sendResponseHeaders(HttpStatus.SC_OK, responseBody.length);
exchange.getResponseBody().write(responseBody);
}
}
});

final InetSocketAddress address = httpServer.getAddress();
final String endpoint = "http://" + InetAddresses.toUriString(address.getAddress()) + ":" + address.getPort();
final MockSecureSettings mockSecure = new MockSecureSettings();
mockSecure.setString(Ec2ClientSettings.ACCESS_KEY_SETTING.getKey(), accessKey);
mockSecure.setString(Ec2ClientSettings.SECRET_KEY_SETTING.getKey(), "ec2_secret");
try (Ec2DiscoveryPlugin plugin = new Ec2DiscoveryPlugin(
Settings.builder().put(Ec2ClientSettings.ENDPOINT_SETTING.getKey(), endpoint).setSecureSettings(mockSecure).build())) {
final SeedHostsProvider seedHostsProvider = plugin.getSeedHostProviders(transportService, networkService).get("ec2").get();
final SeedHostsResolver resolver = new SeedHostsResolver("test", Settings.EMPTY, transportService, seedHostsProvider);
resolver.start();
final List<TransportAddress> addressList = seedHostsProvider.getSeedAddresses(resolver);
assertThat(addressList, Matchers.hasSize(1));
assertThat(addressList.get(0).toString(), is(hosts.get(0)));
assertThat(failedRequests, hasSize(1));
}
}

/**
* Generates a XML response that describe the EC2 instances
* TODO: org.elasticsearch.discovery.ec2.AmazonEC2Fixture uses pretty much the same code. We should dry up that test fixture.
*/
private byte[] generateDescribeInstancesResponse(List<String> nodes) {
final XMLOutputFactory xmlOutputFactory = XMLOutputFactory.newFactory();
xmlOutputFactory.setProperty(XMLOutputFactory.IS_REPAIRING_NAMESPACES, true);

final StringWriter out = new StringWriter();
XMLStreamWriter sw;
try {
sw = xmlOutputFactory.createXMLStreamWriter(out);
sw.writeStartDocument();

String namespace = "http://ec2.amazonaws.com/doc/2013-02-01/";
sw.setDefaultNamespace(namespace);
sw.writeStartElement(XMLConstants.DEFAULT_NS_PREFIX, "DescribeInstancesResponse", namespace);
{
sw.writeStartElement("requestId");
sw.writeCharacters(UUID.randomUUID().toString());
sw.writeEndElement();

sw.writeStartElement("reservationSet");
{
for (String address : nodes) {
sw.writeStartElement("item");
{
sw.writeStartElement("reservationId");
sw.writeCharacters(UUID.randomUUID().toString());
sw.writeEndElement();

sw.writeStartElement("instancesSet");
{
sw.writeStartElement("item");
{
sw.writeStartElement("instanceId");
sw.writeCharacters(UUID.randomUUID().toString());
sw.writeEndElement();

sw.writeStartElement("imageId");
sw.writeCharacters(UUID.randomUUID().toString());
sw.writeEndElement();

sw.writeStartElement("instanceState");
{
sw.writeStartElement("code");
sw.writeCharacters("16");
sw.writeEndElement();

sw.writeStartElement("name");
sw.writeCharacters("running");
sw.writeEndElement();
}
sw.writeEndElement();

sw.writeStartElement("privateDnsName");
sw.writeCharacters(address);
sw.writeEndElement();

sw.writeStartElement("dnsName");
sw.writeCharacters(address);
sw.writeEndElement();

sw.writeStartElement("instanceType");
sw.writeCharacters("m1.medium");
sw.writeEndElement();

sw.writeStartElement("placement");
{
sw.writeStartElement("availabilityZone");
sw.writeCharacters("use-east-1e");
sw.writeEndElement();

sw.writeEmptyElement("groupName");

sw.writeStartElement("tenancy");
sw.writeCharacters("default");
sw.writeEndElement();
}
sw.writeEndElement();

sw.writeStartElement("privateIpAddress");
sw.writeCharacters(address);
sw.writeEndElement();

sw.writeStartElement("ipAddress");
sw.writeCharacters(address);
sw.writeEndElement();
}
sw.writeEndElement();
}
sw.writeEndElement();
}
sw.writeEndElement();
}
sw.writeEndElement();
}
sw.writeEndElement();

sw.writeEndDocument();
sw.flush();
}
} catch (Exception e) {
throw new RuntimeException(e);
}
return out.toString().getBytes(UTF_8);
}
}