Added retry logic if client request returns an error code that is con…

…figured for retrying

Closes #4408

Added additional tests for coverage

Included example of comma separated values for retry-error-codes config parameter

Simplified retry loop logic

Moved retry configurations into constructor and removed setters

Signed-off-by: Allan Clements <criminosis@gmail.com>

docs/configs/janusgraph-cfg.md

@@ -156,6 +156,10 @@ Elasticsearch index configuration
 | index.[X].elasticsearch.enable_index_names_cache | Enables cache for generated index store names. It is recommended to always enable index store names cache unless you have more then 50000 indexes per index store. | Boolean | true | MASKABLE |
 | index.[X].elasticsearch.health-request-timeout | When JanusGraph initializes its ES backend, JanusGraph waits up to this duration for the ES cluster health to reach at least yellow status.  This string should be formatted as a natural number followed by the lowercase letter "s", e.g. 3s or 60s. | String | 30s | MASKABLE |
 | index.[X].elasticsearch.interface | Interface for connecting to Elasticsearch. TRANSPORT_CLIENT and NODE were previously supported, but now are required to migrate to REST_CLIENT. See the JanusGraph upgrade instructions for more details. | String | REST_CLIENT | MASKABLE |
+| index.[X].elasticsearch.retry-error-codes | Comma separated list of Elasticsearch REST client ResponseException error codes to retry. E.g. "408,429" | String[] |  | LOCAL |
+| index.[X].elasticsearch.retry-initial-wait | Sets the initial retry wait time (in milliseconds) before exponential backoff. | Long | 1 | LOCAL |
+| index.[X].elasticsearch.retry-limit | Sets the number of attempts for configured retryable error codes. | Integer | 0 | LOCAL |
+| index.[X].elasticsearch.retry-max-wait | Sets the max retry wait time (in milliseconds). | Long | 1000 | LOCAL |
 | index.[X].elasticsearch.retry_on_conflict | Specify how many times should the operation be retried when a conflict occurs. | Integer | 0 | MASKABLE |
 | index.[X].elasticsearch.scroll-keep-alive | How long (in seconds) elasticsearch should keep alive the scroll context. | Integer | 60 | GLOBAL_OFFLINE |
 | index.[X].elasticsearch.setup-max-open-scroll-contexts | Whether JanusGraph should setup max_open_scroll_context to maximum value for the cluster or not. | Boolean | true | MASKABLE |

janusgraph-es/src/main/java/org/janusgraph/diskstorage/es/ElasticSearchIndex.java

@@ -304,6 +304,26 @@ public class ElasticSearchIndex implements IndexProvider {
             "Sets the maximum socket timeout (in milliseconds).", ConfigOption.Type.MASKABLE,
             Integer.class, RestClientBuilder.DEFAULT_SOCKET_TIMEOUT_MILLIS);
 
+    public static final ConfigOption<Integer> RETRY_LIMIT =
+        new ConfigOption<>(ELASTICSEARCH_NS, "retry-limit",
+            "Sets the number of attempts for configured retryable error codes.", ConfigOption.Type.LOCAL,
+            Integer.class, 0);
+
+    public static final ConfigOption<Long> RETRY_INITIAL_WAIT =
+        new ConfigOption<>(ELASTICSEARCH_NS, "retry-initial-wait",
+            "Sets the initial retry wait time (in milliseconds) before exponential backoff.",
+            ConfigOption.Type.LOCAL, Long.class, 1L);
+
+    public static final ConfigOption<Long> RETRY_MAX_WAIT =
+        new ConfigOption<>(ELASTICSEARCH_NS, "retry-max-wait",
+            "Sets the max retry wait time (in milliseconds).", ConfigOption.Type.LOCAL,
+            Long.class, 1000L);
+
+    public static final ConfigOption<String[]> RETRY_ERROR_CODES =
+        new ConfigOption<>(ELASTICSEARCH_NS, "retry-error-codes",
+            "Comma separated list of Elasticsearch REST client ResponseException error codes to retry. " +
+                "E.g. \"408,429\"", ConfigOption.Type.LOCAL, String[].class, new String[0]);
+
     public static final int HOST_PORT_DEFAULT = 9200;
 
     /**

janusgraph-es/src/main/java/org/janusgraph/diskstorage/es/rest/RestClientSetup.java

@@ -39,8 +39,11 @@
 import java.io.IOException;
 import java.lang.reflect.Constructor;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 import static org.janusgraph.graphdb.configuration.GraphDatabaseConfiguration.INDEX_HOSTS;
 import static org.janusgraph.graphdb.configuration.GraphDatabaseConfiguration.INDEX_PORT;
@@ -73,7 +76,13 @@ public ElasticSearchClient connect(Configuration config) throws IOException {
         final int scrollKeepAlive = config.get(ElasticSearchIndex.ES_SCROLL_KEEP_ALIVE);
         Preconditions.checkArgument(scrollKeepAlive >= 1, "Scroll keep-alive should be greater than or equal to 1");
         final boolean useMappingTypesForES7 = config.get(ElasticSearchIndex.USE_MAPPING_FOR_ES7);
-        final RestElasticSearchClient client = getElasticSearchClient(rc, scrollKeepAlive, useMappingTypesForES7);
+        int retryLimit = config.getOrDefault(ElasticSearchIndex.RETRY_LIMIT);
+        long retryInitialWaitMs = config.getOrDefault(ElasticSearchIndex.RETRY_INITIAL_WAIT);
+        long retryMaxWaitMs = config.getOrDefault(ElasticSearchIndex.RETRY_MAX_WAIT);
+        Set<Integer> errorCodesToRetry = Arrays.stream(config.getOrDefault(ElasticSearchIndex.RETRY_ERROR_CODES))
+            .mapToInt(Integer::parseInt).boxed().collect(Collectors.toSet());
+        final RestElasticSearchClient client = getElasticSearchClient(rc, scrollKeepAlive, useMappingTypesForES7,
+            retryLimit, errorCodesToRetry, retryInitialWaitMs, retryMaxWaitMs);
         if (config.has(ElasticSearchIndex.BULK_REFRESH)) {
             client.setBulkRefresh(config.get(ElasticSearchIndex.BULK_REFRESH));
         }
@@ -104,8 +113,11 @@ protected RestClientBuilder getRestClientBuilder(HttpHost[] hosts) {
         return RestClient.builder(hosts);
     }
 
-    protected RestElasticSearchClient getElasticSearchClient(RestClient rc, int scrollKeepAlive, boolean useMappingTypesForES7) {
-        return new RestElasticSearchClient(rc, scrollKeepAlive, useMappingTypesForES7);
+    protected RestElasticSearchClient getElasticSearchClient(RestClient rc, int scrollKeepAlive, boolean useMappingTypesForES7,
+                                                             int retryAttemptLimit, Set<Integer> retryOnErrorCodes, long retryInitialWaitMs,
+                                                             long retryMaxWaitMs) {
+        return new RestElasticSearchClient(rc, scrollKeepAlive, useMappingTypesForES7, retryAttemptLimit, retryOnErrorCodes,
+            retryInitialWaitMs, retryMaxWaitMs);
     }
 
     /**

janusgraph-es/src/main/java/org/janusgraph/diskstorage/es/rest/RestElasticSearchClient.java

@@ -47,10 +47,12 @@
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -110,14 +112,28 @@ public class RestElasticSearchClient implements ElasticSearchClient {
     private Integer retryOnConflict;
 
     private final String retryOnConflictKey;
-
-    public RestElasticSearchClient(RestClient delegate, int scrollKeepAlive, boolean useMappingTypesForES7) {
+
+    private final int retryAttemptLimit;
+
+    private final Set<Integer> retryOnErrorCodes;
+
+    private final long retryInitialWaitMs;
+
+    private final long retryMaxWaitMs;
+
+public RestElasticSearchClient(RestClient delegate, int scrollKeepAlive, boolean useMappingTypesForES7,
+                               int retryAttemptLimit, Set<Integer> retryOnErrorCodes, long retryInitialWaitMs,
+                               long retryMaxWaitMs) {
         this.delegate = delegate;
         majorVersion = getMajorVersion();
         this.scrollKeepAlive = scrollKeepAlive+"s";
         esVersion7 = ElasticMajorVersion.SEVEN.equals(majorVersion);
         useMappingTypes = majorVersion.getValue() < 7 || (useMappingTypesForES7 && esVersion7);
         retryOnConflictKey = majorVersion.getValue() >= 7 ? "retry_on_conflict" : "_retry_on_conflict";
+        this.retryAttemptLimit = retryAttemptLimit;
+        this.retryOnErrorCodes = Collections.unmodifiableSet(retryOnErrorCodes);
+        this.retryInitialWaitMs = retryInitialWaitMs;
+        this.retryMaxWaitMs = retryMaxWaitMs;
     }
 
     @Override
@@ -546,13 +562,35 @@ private Response performRequest(String method, String path, byte[] requestData)
         return performRequest(new Request(method, path), requestData);
     }
 
+    private Response performRequestWithRetry(Request request) throws IOException {
+        int retryCount = 0;
+        while (true) {
+            try {
+                return delegate.performRequest(request);
+            } catch (ResponseException e) {
+                if (!retryOnErrorCodes.contains(e.getResponse().getStatusLine().getStatusCode()) || retryCount >= retryAttemptLimit) {
+                    throw e;
+                }
+                //Wait before trying again
+                long waitDurationMs = Math.min((long) (retryInitialWaitMs * Math.pow(10, retryCount)), retryMaxWaitMs);
+                log.warn("Retrying Elasticsearch request in {} ms. Attempt {} of {}", waitDurationMs, retryCount, retryAttemptLimit);
+                try {
+                    Thread.sleep(waitDurationMs);
+                } catch (InterruptedException interruptedException) {
+                    throw new RuntimeException(String.format("Thread interrupted while waiting for retry attempt %d of %d", retryCount, retryAttemptLimit), interruptedException);
+                }
+            }
+            retryCount++;
+        }
+    }
+
     private Response performRequest(Request request, byte[] requestData) throws IOException {
 
         final HttpEntity entity = requestData != null ? new ByteArrayEntity(requestData, ContentType.APPLICATION_JSON) : null;
 
         request.setEntity(entity);
 
-        final Response response = delegate.performRequest(request);
+        final Response response = performRequestWithRetry(request);
 
         if (response.getStatusLine().getStatusCode() >= 400) {
             throw new IOException("Error executing request: " + response.getStatusLine().getReasonPhrase());

janusgraph-es/src/test/java/org/janusgraph/diskstorage/es/rest/RestClientRetryTest.java

@@ -0,0 +1,156 @@
+// Copyright 2024 JanusGraph Authors
+//
+// 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 org.janusgraph.diskstorage.es.rest;
+
+import com.google.common.collect.Sets;
+import org.apache.http.StatusLine;
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.Response;
+import org.elasticsearch.client.ResponseException;
+import org.elasticsearch.client.RestClient;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Set;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+public class RestClientRetryTest {
+    @Mock
+    private RestClient restClientMock;
+
+    @Mock
+    private ResponseException responseException;
+
+    @Mock
+    private Response response;
+
+    @Mock
+    private StatusLine statusLine;
+
+    @Captor
+    private ArgumentCaptor<Request> requestCaptor;
+
+    RestElasticSearchClient createClient(int retryAttemptLimit, Set<Integer> retryErrorCodes) throws IOException {
+        //Just throw an exception when there's an attempt to look up the ES version during instantiation
+        when(restClientMock.performRequest(any())).thenThrow(new IOException());
+
+        RestElasticSearchClient clientUnderTest = new RestElasticSearchClient(restClientMock, 0, false,
+            retryAttemptLimit, retryErrorCodes, 0, 0);
+        //There's an initial query to get the ES version we need to accommodate, and then reset for the actual test
+        Mockito.reset(restClientMock);
+        return clientUnderTest;
+    }
+
+    @Test
+    public void testRetryOnConfiguredErrorStatus() throws IOException {
+        Integer retryCode = 429;
+        int expectedNumberOfRequestAttempts = 2;
+        doReturn(retryCode).when(statusLine).getStatusCode();
+        doReturn(statusLine).when(response).getStatusLine();
+        doReturn(response).when(responseException).getResponse();
+        //Just throw an expected exception the second time to confirm the retry occurred
+        //rather than mock out a parsable response
+        IOException expectedFinalException = new IOException("Expected");
+
+        try (RestElasticSearchClient restClientUnderTest = createClient(expectedNumberOfRequestAttempts - 1,
+            Sets.newHashSet(retryCode))) {
+            //prime the restClientMock again after it's reset after creation
+            when(restClientMock.performRequest(any()))
+                .thenThrow(responseException)
+                .thenThrow(expectedFinalException);
+            restClientUnderTest.bulkRequest(Collections.emptyList(), null);
+            Assertions.fail("Should have thrown the expected exception after retry");
+        } catch (Exception actualException) {
+            Assertions.assertSame(expectedFinalException, actualException);
+        }
+        verify(restClientMock, times(expectedNumberOfRequestAttempts)).performRequest(requestCaptor.capture());
+    }
+
+    @Test
+    public void testRetriesExhaustedReturnsLastRetryException() throws IOException {
+        Integer retryCode = 429;
+        int expectedNumberOfRequestAttempts = 2;
+        doReturn(retryCode).when(statusLine).getStatusCode();
+        doReturn(statusLine).when(response).getStatusLine();
+        doReturn(response).when(responseException).getResponse();
+        ResponseException initialRetryException = mock(ResponseException.class);
+        doReturn(response).when(initialRetryException).getResponse();
+
+        try (RestElasticSearchClient restClientUnderTest = createClient(expectedNumberOfRequestAttempts - 1,
+            Sets.newHashSet(retryCode))) {
+            //prime the restClientMock again after it's reset after creation
+            when(restClientMock.performRequest(any()))
+                //first throw a different retry exception instance, then make sure it's the latter one
+                //that was retained and then thrown
+                .thenThrow(initialRetryException)
+                .thenThrow(responseException);
+
+
+            restClientUnderTest.bulkRequest(Collections.emptyList(), null);
+            Assertions.fail("Should have thrown the expected exception after retry");
+        } catch (Exception e) {
+            Assertions.assertSame(responseException, e);
+        }
+        verify(restClientMock, times(expectedNumberOfRequestAttempts)).performRequest(requestCaptor.capture());
+    }
+
+    @Test
+    public void testNonRetryErrorCodeException() throws IOException {
+        doReturn(503).when(statusLine).getStatusCode();
+        doReturn(statusLine).when(response).getStatusLine();
+        doReturn(response).when(responseException).getResponse();
+        try (RestElasticSearchClient restClientUnderTest = createClient(0,
+            //Other retry error code is configured
+            Sets.newHashSet(429))) {
+            //prime the restClientMock again after it's reset after creation
+            when(restClientMock.performRequest(any()))
+                .thenThrow(responseException);
+            restClientUnderTest.bulkRequest(Collections.emptyList(), null);
+            Assertions.fail("Should have thrown the expected exception");
+        } catch (Exception e) {
+            Assertions.assertSame(responseException, e);
+        }
+        verify(restClientMock, times(1)).performRequest(requestCaptor.capture());
+    }
+
+    @Test
+    public void testNonResponseExceptionErrorThrown() throws IOException {
+        IOException differentExceptionType = new IOException();
+        when(restClientMock.performRequest(any()))
+            .thenThrow(differentExceptionType);
+        try (RestElasticSearchClient restClientUnderTest = createClient(0, Collections.emptySet())) {
+            restClientUnderTest.bulkRequest(Collections.emptyList(), null);
+            Assertions.fail("Should have thrown the expected exception");
+        } catch (Exception e) {
+            Assertions.assertSame(differentExceptionType, e);
+        }
+        verify(restClientMock, times(1)).performRequest(requestCaptor.capture());
+    }
+}