Create ES ConfigOption MAX_RETRIES_IN_MILLIS

The ES RestClient does [not
support](elastic/elasticsearch#21789 (comment))
a per request timeout configuration, however it does at least support a
timeout configuration option `maxRetriesInMillis` that will timeout the
overall request, including retries. It can be useful for others to
configure this timeout, especially given the fact that users can
configure their gremlin-script-execution timeout.

Issues: JanusGraph#688

Signed-off-by: David Pitera <[email protected]>

Author: dpitera

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

@@ -122,6 +122,11 @@ public class ElasticSearchIndex implements IndexProvider {
             "This string should be formatted as a natural number followed by the lowercase letter " +
             "\"s\", e.g. 3s or 60s.", ConfigOption.Type.MASKABLE, "30s");
 
+    public static final ConfigOption<Integer> MAX_RETRY_TIMEOUT =
+            new ConfigOption<>(ELASTICSEARCH_NS, "max-retry-timeout",
+            "Sets the maximum timeout (in milliseconds) to honour in case of multiple retries of the same request " +
+            "sent using the ElasticSearch Rest Client by JanusGraph.", ConfigOption.Type.MASKABLE, Integer.class);
+
     public static final ConfigOption<String> BULK_REFRESH =
             new ConfigOption<>(ELASTICSEARCH_NS, "bulk-refresh",
             "Elasticsearch bulk API refresh setting used to control when changes made by this request are made " +

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

@@ -18,6 +18,7 @@
 import com.google.common.base.Preconditions;
 import org.apache.http.HttpHost;
 import org.elasticsearch.client.RestClient;
+import org.elasticsearch.client.RestClientBuilder;
 import org.janusgraph.diskstorage.configuration.ConfigNamespace;
 import org.janusgraph.diskstorage.configuration.Configuration;
 import org.janusgraph.diskstorage.es.rest.RestElasticSearchClient;
@@ -66,7 +67,11 @@ public Connection connect(Configuration config) throws IOException {
                 log.debug("Configured remote host: {} : {}", hostname, hostport);
                 hosts.add(new HttpHost(hostname, hostport, "http"));
             }
-            RestClient rc = RestClient.builder(hosts.toArray(new HttpHost[hosts.size()])).build();
+            final RestClientBuilder rcb = RestClient.builder(hosts.toArray(new HttpHost[hosts.size()]));
+            if (config.has(ElasticSearchIndex.MAX_RETRY_TIMEOUT)) {
+                rcb.setMaxRetryTimeoutMillis(config.get(ElasticSearchIndex.MAX_RETRY_TIMEOUT));
+            }
+            final RestClient rc = rcb.build();
 
             final int scrollKeepAlive = config.get(ElasticSearchIndex.ES_SCROLL_KEEP_ALIVE);
             Preconditions.checkArgument(scrollKeepAlive >= 1, "Scroll Keep alive should be greater or equals than 1");