Replicate aliases in cross-cluster replication (elastic#41815)

This commit adds functionality so that aliases that are manipulated on
leader indices are replicated by the shard follow tasks to the follower
indices. Note that we ignore write indices. This is due to the fact that
follower indices do not receive direct writes so the concept is not
useful.

client/rest-high-level/src/main/java/org/elasticsearch/client/ccr/IndicesFollowStats.java

@@ -101,6 +101,7 @@ public static final class ShardFollowStats {
         static final ParseField WRITE_BUFFER_SIZE_IN_BYTES_FIELD = new ParseField("write_buffer_size_in_bytes");
         static final ParseField FOLLOWER_MAPPING_VERSION_FIELD = new ParseField("follower_mapping_version");
         static final ParseField FOLLOWER_SETTINGS_VERSION_FIELD = new ParseField("follower_settings_version");
+        static final ParseField FOLLOWER_ALIASES_VERSION_FIELD = new ParseField("follower_aliases_version");
         static final ParseField TOTAL_READ_TIME_MILLIS_FIELD = new ParseField("total_read_time_millis");
         static final ParseField TOTAL_READ_REMOTE_EXEC_TIME_MILLIS_FIELD = new ParseField("total_read_remote_exec_time_millis");
         static final ParseField SUCCESSFUL_READ_REQUESTS_FIELD = new ParseField("successful_read_requests");
@@ -117,41 +118,42 @@ public static final class ShardFollowStats {
 
         @SuppressWarnings("unchecked")
         static final ConstructingObjectParser<ShardFollowStats, Void> PARSER =
-            new ConstructingObjectParser<>(
-                "shard-follow-stats",
-                true,
-                args -> new ShardFollowStats(
-                    (String) args[0],
-                    (String) args[1],
-                    (String) args[2],
-                    (int) args[3],
-                    (long) args[4],
-                    (long) args[5],
-                    (long) args[6],
-                    (long) args[7],
-                    (long) args[8],
-                    (int) args[9],
-                    (int) args[10],
-                    (int) args[11],
-                    (long) args[12],
-                    (long) args[13],
-                    (long) args[14],
-                    (long) args[15],
-                    (long) args[16],
-                    (long) args[17],
-                    (long) args[18],
-                    (long) args[19],
-                    (long) args[20],
-                    (long) args[21],
-                    (long) args[22],
-                    (long) args[23],
-                    (long) args[24],
-                    (long) args[25],
-                    new TreeMap<>(
-                        ((List<Map.Entry<Long, Tuple<Integer, ElasticsearchException>>>) args[26])
-                            .stream()
-                            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))),
-                    (ElasticsearchException) args[27]));
+                new ConstructingObjectParser<>(
+                        "shard-follow-stats",
+                        true,
+                        args -> new ShardFollowStats(
+                                (String) args[0],
+                                (String) args[1],
+                                (String) args[2],
+                                (int) args[3],
+                                (long) args[4],
+                                (long) args[5],
+                                (long) args[6],
+                                (long) args[7],
+                                (long) args[8],
+                                (int) args[9],
+                                (int) args[10],
+                                (int) args[11],
+                                (long) args[12],
+                                (long) args[13],
+                                (long) args[14],
+                                (long) args[15],
+                                (long) args[16],
+                                (long) args[17],
+                                (long) args[18],
+                                (long) args[19],
+                                (long) args[20],
+                                (long) args[21],
+                                (long) args[22],
+                                (long) args[23],
+                                (long) args[24],
+                                (long) args[25],
+                                (long) args[26],
+                                new TreeMap<>(
+                                        ((List<Map.Entry<Long, Tuple<Integer, ElasticsearchException>>>) args[27])
+                                                .stream()
+                                                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))),
+                                (ElasticsearchException) args[28]));
 
         static final ConstructingObjectParser<Map.Entry<Long, Tuple<Integer, ElasticsearchException>>, Void> READ_EXCEPTIONS_ENTRY_PARSER =
             new ConstructingObjectParser<>(
@@ -175,6 +177,7 @@ public static final class ShardFollowStats {
             PARSER.declareLong(ConstructingObjectParser.constructorArg(), WRITE_BUFFER_SIZE_IN_BYTES_FIELD);
             PARSER.declareLong(ConstructingObjectParser.constructorArg(), FOLLOWER_MAPPING_VERSION_FIELD);
             PARSER.declareLong(ConstructingObjectParser.constructorArg(), FOLLOWER_SETTINGS_VERSION_FIELD);
+            PARSER.declareLong(ConstructingObjectParser.constructorArg(), FOLLOWER_ALIASES_VERSION_FIELD);
             PARSER.declareLong(ConstructingObjectParser.constructorArg(), TOTAL_READ_TIME_MILLIS_FIELD);
             PARSER.declareLong(ConstructingObjectParser.constructorArg(), TOTAL_READ_REMOTE_EXEC_TIME_MILLIS_FIELD);
             PARSER.declareLong(ConstructingObjectParser.constructorArg(), SUCCESSFUL_READ_REQUESTS_FIELD);
@@ -220,6 +223,7 @@ public static final class ShardFollowStats {
         private final long writeBufferSizeInBytes;
         private final long followerMappingVersion;
         private final long followerSettingsVersion;
+        private final long followerAliasesVersion;
         private final long totalReadTimeMillis;
         private final long totalReadRemoteExecTimeMillis;
         private final long successfulReadRequests;
@@ -249,6 +253,7 @@ public static final class ShardFollowStats {
                          long writeBufferSizeInBytes,
                          long followerMappingVersion,
                          long followerSettingsVersion,
+                         long followerAliasesVersion,
                          long totalReadTimeMillis,
                          long totalReadRemoteExecTimeMillis,
                          long successfulReadRequests,
@@ -277,6 +282,7 @@ public static final class ShardFollowStats {
             this.writeBufferSizeInBytes = writeBufferSizeInBytes;
             this.followerMappingVersion = followerMappingVersion;
             this.followerSettingsVersion = followerSettingsVersion;
+            this.followerAliasesVersion = followerAliasesVersion;
             this.totalReadTimeMillis = totalReadTimeMillis;
             this.totalReadRemoteExecTimeMillis = totalReadRemoteExecTimeMillis;
             this.successfulReadRequests = successfulReadRequests;
@@ -352,6 +358,10 @@ public long getFollowerSettingsVersion() {
             return followerSettingsVersion;
         }
 
+        public long getFollowerAliasesVersion() {
+            return followerAliasesVersion;
+        }
+
         public long getTotalReadTimeMillis() {
             return totalReadTimeMillis;
         }

client/rest-high-level/src/test/java/org/elasticsearch/client/ccr/CcrStatsResponseTests.java

@@ -106,6 +106,7 @@ static FollowStatsAction.StatsResponses createStatsResponse() {
                 randomNonNegativeLong(),
                 randomNonNegativeLong(),
                 randomNonNegativeLong(),
+                randomNonNegativeLong(),
                 Collections.emptyNavigableMap(),
                 randomLong(),
                 randomBoolean() ? new ElasticsearchException("fatal error") : null);
@@ -190,6 +191,8 @@ protected void assertInstances(CcrStatsAction.Response serverTestInstance, CcrSt
                         equalTo(expectedShardFollowStats.followerMappingVersion()));
                     assertThat(actualShardFollowStats.getFollowerSettingsVersion(),
                         equalTo(expectedShardFollowStats.followerSettingsVersion()));
+                    assertThat(actualShardFollowStats.getFollowerAliasesVersion(),
+                            equalTo(expectedShardFollowStats.followerAliasesVersion()));
                     assertThat(actualShardFollowStats.getTotalReadTimeMillis(),
                         equalTo(expectedShardFollowStats.totalReadTimeMillis()));
                     assertThat(actualShardFollowStats.getSuccessfulReadRequests(),

client/rest-high-level/src/test/java/org/elasticsearch/client/ccr/FollowStatsResponseTests.java

@@ -93,6 +93,8 @@ protected void assertInstances(FollowStatsAction.StatsResponses serverTestInstan
                     equalTo(expectedShardFollowStats.followerMappingVersion()));
                 assertThat(actualShardFollowStats.getFollowerSettingsVersion(),
                     equalTo(expectedShardFollowStats.followerSettingsVersion()));
+                assertThat(actualShardFollowStats.getFollowerAliasesVersion(),
+                        equalTo(expectedShardFollowStats.followerAliasesVersion()));
                 assertThat(actualShardFollowStats.getTotalReadTimeMillis(),
                     equalTo(expectedShardFollowStats.totalReadTimeMillis()));
                 assertThat(actualShardFollowStats.getSuccessfulReadRequests(),

docs/reference/ccr/apis/follow/get-follow-stats.asciidoc

@@ -114,6 +114,9 @@ The `shards` array consists of objects containing the following fields:
 `indices[].shards[].follower_settings_version`::
   (long) the index settings version the follower is synced up to
 
+`indices[].shards[].follower_aliases_version`::
+  (long) the index aliases version the follower is synced up to
+
 `indices[].shards[].total_read_time_millis`::
   (long) the total time reads were outstanding, measured from the time a read
   was sent to the leader to the time a reply was returned to the follower
@@ -217,6 +220,7 @@ The API returns the following results:
           "write_buffer_operation_count" : 64,
           "follower_mapping_version" : 4,
           "follower_settings_version" : 2,
+          "follower_aliases_version" : 8,
           "total_read_time_millis" : 32768,
           "total_read_remote_exec_time_millis" : 16384,
           "successful_read_requests" : 32,
@@ -246,6 +250,7 @@ The API returns the following results:
 // TESTRESPONSE[s/"write_buffer_operation_count" : 64/"write_buffer_operation_count" : $body.indices.0.shards.0.write_buffer_operation_count/]
 // TESTRESPONSE[s/"follower_mapping_version" : 4/"follower_mapping_version" : $body.indices.0.shards.0.follower_mapping_version/]
 // TESTRESPONSE[s/"follower_settings_version" : 2/"follower_settings_version" : $body.indices.0.shards.0.follower_settings_version/]
+// TESTRESPONSE[s/"follower_aliases_version" : 8/"follower_aliases_version" : $body.indices.0.shards.0.follower_aliases_version/]
 // TESTRESPONSE[s/"total_read_time_millis" : 32768/"total_read_time_millis" : $body.indices.0.shards.0.total_read_time_millis/]
 // TESTRESPONSE[s/"total_read_remote_exec_time_millis" : 16384/"total_read_remote_exec_time_millis" : $body.indices.0.shards.0.total_read_remote_exec_time_millis/]
 // TESTRESPONSE[s/"successful_read_requests" : 32/"successful_read_requests" : $body.indices.0.shards.0.successful_read_requests/]

docs/reference/ccr/apis/get-ccr-stats.asciidoc

@@ -126,6 +126,7 @@ The API returns the following results:
             "write_buffer_operation_count" : 64,
             "follower_mapping_version" : 4,
             "follower_settings_version" : 2,
+            "follower_aliases_version" : 8,
             "total_read_time_millis" : 32768,
             "total_read_remote_exec_time_millis" : 16384,
             "successful_read_requests" : 32,
@@ -161,6 +162,7 @@ The API returns the following results:
 // TESTRESPONSE[s/"write_buffer_operation_count" : 64/"write_buffer_operation_count" : $body.follow_stats.indices.0.shards.0.write_buffer_operation_count/]
 // TESTRESPONSE[s/"follower_mapping_version" : 4/"follower_mapping_version" : $body.follow_stats.indices.0.shards.0.follower_mapping_version/]
 // TESTRESPONSE[s/"follower_settings_version" : 2/"follower_settings_version" : $body.follow_stats.indices.0.shards.0.follower_settings_version/]
+// TESTRESPONSE[s/"follower_aliases_version" : 8/"follower_aliases_version" : $body.follow_stats.indices.0.shards.0.follower_aliases_version/]
 // TESTRESPONSE[s/"total_read_time_millis" : 32768/"total_read_time_millis" : $body.follow_stats.indices.0.shards.0.total_read_time_millis/]
 // TESTRESPONSE[s/"total_read_remote_exec_time_millis" : 16384/"total_read_remote_exec_time_millis" : $body.follow_stats.indices.0.shards.0.total_read_remote_exec_time_millis/]
 // TESTRESPONSE[s/"successful_read_requests" : 32/"successful_read_requests" : $body.follow_stats.indices.0.shards.0.successful_read_requests/]

server/src/main/java/org/elasticsearch/cluster/metadata/AliasMetaData.java

@@ -140,15 +140,13 @@ public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
 
-        AliasMetaData that = (AliasMetaData) o;
+        final AliasMetaData that = (AliasMetaData) o;
 
         if (alias != null ? !alias.equals(that.alias) : that.alias != null) return false;
         if (filter != null ? !filter.equals(that.filter) : that.filter != null) return false;
         if (indexRouting != null ? !indexRouting.equals(that.indexRouting) : that.indexRouting != null) return false;
-        if (searchRouting != null ? !searchRouting.equals(that.searchRouting) : that.searchRouting != null)
-            return false;
-        if (writeIndex != null ? writeIndex != that.writeIndex : that.writeIndex != null)
-            return false;
+        if (searchRouting != null ? !searchRouting.equals(that.searchRouting) : that.searchRouting != null) return false;
+        if (writeIndex != null ? writeIndex != that.writeIndex : that.writeIndex != null) return false;
 
         return true;
     }

x-pack/plugin/ccr/qa/src/main/java/org/elasticsearch/xpack/ccr/ESCCRRestTestCase.java

@@ -143,6 +143,7 @@ protected static void verifyCcrMonitoring(final String expectedLeaderIndex, fina
         int followerMaxSeqNo = 0;
         int followerMappingVersion = 0;
         int followerSettingsVersion = 0;
+        int followerAliasesVersion = 0;
 
         List<?> hits = (List<?>) XContentMapValues.extractValue("hits.hits", response);
         assertThat(hits.size(), greaterThanOrEqualTo(1));
@@ -164,11 +165,15 @@ protected static void verifyCcrMonitoring(final String expectedLeaderIndex, fina
             int foundFollowerSettingsVersion =
                     (int) XContentMapValues.extractValue("_source.ccr_stats.follower_settings_version", hit);
             followerSettingsVersion = Math.max(followerSettingsVersion, foundFollowerSettingsVersion);
+            int foundFollowerAliasesVersion =
+                    (int) XContentMapValues.extractValue("_source.ccr_stats.follower_aliases_version", hit);
+            followerAliasesVersion = Math.max(followerAliasesVersion, foundFollowerAliasesVersion);
         }
 
         assertThat(followerMaxSeqNo, greaterThan(0));
         assertThat(followerMappingVersion, greaterThan(0));
         assertThat(followerSettingsVersion, greaterThan(0));
+        assertThat(followerAliasesVersion, greaterThan(0));
     }
 
     protected static void verifyAutoFollowMonitoring() throws IOException {