From f8ebb75fcfd8b313cd69affe2166606abf87e7b2 Mon Sep 17 00:00:00 2001
From: Martijn van Groningen <martijn.v.groningen@gmail.com>
Date: Wed, 9 Oct 2019 17:31:10 +0200
Subject: [PATCH] Reuse OperationRouting#searchShards(...) to select local
 enrich shard (#47359)

The currently logic shard selecting logic selects a random shard copy
instead of selecting the local shard copy and if local copy is not
available then selecting a random shard copy. The latter is desired
behaviour for enrich.

By reusing `OperationRouting#searchShards(...)` we get the desired
behaviour and reuse the same logic that the search api is using.
---
 .../xpack/enrich/action/EnrichShardMultiSearchAction.java | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/x-pack/plugin/enrich/src/main/java/org/elasticsearch/xpack/enrich/action/EnrichShardMultiSearchAction.java b/x-pack/plugin/enrich/src/main/java/org/elasticsearch/xpack/enrich/action/EnrichShardMultiSearchAction.java
index 0faddddf9da..c1144310eec 100644
--- a/x-pack/plugin/enrich/src/main/java/org/elasticsearch/xpack/enrich/action/EnrichShardMultiSearchAction.java
+++ b/x-pack/plugin/enrich/src/main/java/org/elasticsearch/xpack/enrich/action/EnrichShardMultiSearchAction.java
@@ -23,7 +23,10 @@ import org.elasticsearch.action.support.single.shard.SingleShardRequest;
 import org.elasticsearch.action.support.single.shard.TransportSingleShardAction;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
+import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.IndexRoutingTable;
+import org.elasticsearch.cluster.routing.Preference;
+import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardsIterator;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Strings;
@@ -199,7 +202,10 @@ public class EnrichShardMultiSearchAction extends ActionType<MultiSearchResponse
             if (numShards != 1) {
                 throw new IllegalStateException("index [" + index + "] should have 1 shard, but has " + numShards + " shards");
             }
-            return indexRouting.shard(0).shardsRandomIt();
+
+            GroupShardsIterator<ShardIterator> result =
+                clusterService.operationRouting().searchShards(state, new String[] {index}, null, Preference.LOCAL.type());
+            return result.get(0);
         }
 
         @Override