From 0b15e2b3ad2831337154ba5b8e079b46d788153f Mon Sep 17 00:00:00 2001
From: Marc Handalian <handalm@amazon.com>
Date: Thu, 3 Mar 2022 12:47:14 -0800
Subject: [PATCH] Move segment replication setting to IndexMetadata so that it
 can be set during index creation. (#2284)

Signed-off-by: Marc Handalian <handalm@amazon.com>
---
 .../opensearch/cluster/metadata/IndexMetadata.java    | 11 +++++++++++
 .../common/settings/IndexScopedSettings.java          |  1 +
 .../main/java/org/opensearch/index/IndexSettings.java |  7 ++++++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java
index 6510c57060fe0..52ba67bcde583 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java
@@ -260,6 +260,17 @@ public Iterator<Setting<?>> settings() {
         Property.IndexScope
     );
 
+    public static final String SETTING_SEGMENT_REPLICATION = "index.replication.segment_replication";
+    /**
+     * Used to specify if the index should use segment replication. If false, document replication is used.
+     */
+    public static final Setting<Boolean> INDEX_SEGMENT_REPLICATION_SETTING = Setting.boolSetting(
+        SETTING_SEGMENT_REPLICATION,
+        false,
+        Property.IndexScope,
+        Property.Final
+    );
+
     public static final String SETTING_AUTO_EXPAND_REPLICAS = "index.auto_expand_replicas";
     public static final Setting<AutoExpandReplicas> INDEX_AUTO_EXPAND_REPLICAS_SETTING = AutoExpandReplicas.SETTING;
 
diff --git a/server/src/main/java/org/opensearch/common/settings/IndexScopedSettings.java b/server/src/main/java/org/opensearch/common/settings/IndexScopedSettings.java
index 528d6cc9f5e23..bd1e2ed7fb8c6 100644
--- a/server/src/main/java/org/opensearch/common/settings/IndexScopedSettings.java
+++ b/server/src/main/java/org/opensearch/common/settings/IndexScopedSettings.java
@@ -97,6 +97,7 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
                 IndexMetadata.INDEX_DATA_PATH_SETTING,
                 IndexMetadata.INDEX_FORMAT_SETTING,
                 IndexMetadata.INDEX_HIDDEN_SETTING,
+                IndexMetadata.INDEX_SEGMENT_REPLICATION_SETTING,
                 SearchSlowLog.INDEX_SEARCH_SLOWLOG_THRESHOLD_FETCH_DEBUG_SETTING,
                 SearchSlowLog.INDEX_SEARCH_SLOWLOG_THRESHOLD_FETCH_WARN_SETTING,
                 SearchSlowLog.INDEX_SEARCH_SLOWLOG_THRESHOLD_FETCH_INFO_SETTING,
diff --git a/server/src/main/java/org/opensearch/index/IndexSettings.java b/server/src/main/java/org/opensearch/index/IndexSettings.java
index aa69417af1897..60a53a3d54c3f 100644
--- a/server/src/main/java/org/opensearch/index/IndexSettings.java
+++ b/server/src/main/java/org/opensearch/index/IndexSettings.java
@@ -530,6 +530,7 @@ public final class IndexSettings {
     private final String nodeName;
     private final Settings nodeSettings;
     private final int numberOfShards;
+    private final Boolean isSegrepEnabled;
     // volatile fields are updated via #updateIndexMetadata(IndexMetadata) under lock
     private volatile Settings settings;
     private volatile IndexMetadata indexMetadata;
@@ -681,7 +682,7 @@ public IndexSettings(final IndexMetadata indexMetadata, final Settings nodeSetti
         nodeName = Node.NODE_NAME_SETTING.get(settings);
         this.indexMetadata = indexMetadata;
         numberOfShards = settings.getAsInt(IndexMetadata.SETTING_NUMBER_OF_SHARDS, null);
-
+        isSegrepEnabled = settings.getAsBoolean(IndexMetadata.SETTING_SEGMENT_REPLICATION, false);
         this.searchThrottled = INDEX_SEARCH_THROTTLED.get(settings);
         this.queryStringLenient = QUERY_STRING_LENIENT_SETTING.get(settings);
         this.queryStringAnalyzeWildcard = QUERY_STRING_ANALYZE_WILDCARD.get(nodeSettings);
@@ -915,6 +916,10 @@ public int getNumberOfReplicas() {
         return settings.getAsInt(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, null);
     }
 
+    public boolean isSegrepEnabled() {
+        return Boolean.TRUE.equals(isSegrepEnabled);
+    }
+
     /**
      * Returns the node settings. The settings returned from {@link #getSettings()} are a merged version of the
      * index settings and the node settings where node settings are overwritten by index settings.