Make EC2 Discovery Plugin Retry Requests (#50550)

Use the default retry condition instead of never retrying in the discovery plugin causing hot retries upstream and add a test that verifies retrying works.

Closes #50462

plugins/discovery-ec2/src/main/java/org/elasticsearch/discovery/ec2/AwsEc2ServiceImpl.java

@@ -25,21 +25,18 @@ import com.amazonaws.auth.AWSCredentialsProvider;
 import com.amazonaws.auth.AWSStaticCredentialsProvider;
 import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
 import com.amazonaws.http.IdleConnectionReaper;
-import com.amazonaws.retry.RetryPolicy;
 import com.amazonaws.services.ec2.AmazonEC2;
 import com.amazonaws.services.ec2.AmazonEC2Client;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.elasticsearch.ElasticsearchException;
-import org.elasticsearch.common.Randomness;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.util.LazyInitializable;
 
-import java.util.Random;
 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 =
@@ -77,17 +74,7 @@ class AwsEc2ServiceImpl implements AwsEc2Service {
             clientConfiguration.setProxyPassword(clientSettings.proxyPassword);
         }
         // Increase the number of retries in case of 5xx API responses
-        final Random rand = Randomness.get();
-        final RetryPolicy retryPolicy = new RetryPolicy(
-            RetryPolicy.RetryCondition.NO_RETRY_CONDITION,
-            (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);
-               return 1000L * (long) (10d * Math.pow(2, retriesAttempted / 2.0d) * (1.0d + rand.nextDouble()));
-            },
-            10,
-            false);
-        clientConfiguration.setRetryPolicy(retryPolicy);
+        clientConfiguration.setMaxErrorRetry(10);
         clientConfiguration.setSocketTimeout(clientSettings.readTimeoutMillis);
         return clientConfiguration;
     }

plugins/discovery-ec2/src/test/java/org/elasticsearch/discovery/ec2/EC2RetriesTests.java

@@ -0,0 +1,266 @@
+/*
+ * 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.Map;
+import java.util.Objects;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.hamcrest.Matchers.aMapWithSize;
+import static org.hamcrest.Matchers.is;
+
+@SuppressForbidden(reason = "use a http server")
+public class EC2RetriesTests extends ESTestCase {
+
+    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 Map<String, Integer> failedRequests = new ConcurrentHashMap<>();
+        // retry the same request 5 times at most
+        final int maxRetries = randomIntBetween(1, 5);
+        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.compute(exchange.getRequestHeaders().getFirst("Amz-sdk-invocation-id"),
+                        (requestId, count) -> Objects.requireNonNullElse(count, 0) + 1) < maxRetries) {
+                        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);
+                    return;
+                }
+            }
+            fail("did not send response");
+        });
+
+        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, aMapWithSize(1));
+            assertThat(failedRequests.values().iterator().next(), is(maxRetries));
+        }
+    }
+
+    /**
+     * 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);
+    }
+}