New SQL cluster settings endpoint (opendistro-for-elasticsearch#400)

* Add new _sql/settings endpoint, and logic to only affect opendistro.sql settings

* Add integration tests

* Change endpoint HTTP method to PUT

* Update Settings doc

(cherry picked from commit f1d538f)

docs/user/admin/settings.rst

@@ -37,7 +37,7 @@ You can update the setting with a new value like this.
 
 SQL query::
 
-	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_cluster/settings -d '{
+	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_opendistro/_sql/settings -d '{
 	  "transient" : {
 	    "opendistro.sql.enabled" : "false"
 	  }
@@ -99,7 +99,7 @@ You can update the setting with a new value like this.
 
 SQL query::
 
-	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_cluster/settings -d '{
+	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_opendistro/_sql/settings -d '{
 	  "transient" : {
 	    "opendistro.sql.query.slowlog" : "10"
 	  }
@@ -141,7 +141,7 @@ You can update the setting with a new value like this.
 
 SQL query::
 
-	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_cluster/settings -d '{
+	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_opendistro/_sql/settings -d '{
 	  "transient" : {
 	    "opendistro.sql.query.analysis.enabled" : "false"
 	  }
@@ -185,7 +185,7 @@ You can update the setting with a new value like this.
 
 SQL query::
 
-	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_cluster/settings -d '{
+	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_opendistro/_sql/settings -d '{
 	  "transient" : {
 	    "opendistro.sql.query.analysis.semantic.suggestion" : "true"
 	  }
@@ -253,7 +253,7 @@ You can update the setting with a new value like this.
 
 SQL query::
 
-	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_cluster/settings -d '{
+	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_opendistro/_sql/settings -d '{
 	  "transient" : {
 	    "opendistro.sql.query.analysis.semantic.threshold" : "50"
 	  }
@@ -299,7 +299,7 @@ You can update the setting with a new value like this.
 
 SQL query::
 
-	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_cluster/settings -d '{
+	>> curl -H 'Content-Type: application/json' -X PUT localhost:9200/_opendistro/_sql/settings -d '{
 	  "transient" : {
 	    "opendistro.sql.query.response.format" : "json"
 	  }

src/main/java/com/amazon/opendistroforelasticsearch/sql/plugin/RestSqlSettingsAction.java

@@ -0,0 +1,125 @@
+/*
+ *   Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *   Licensed under the Apache License, Version 2.0 (the "License").
+ *   You may not use this file except in compliance with the License.
+ *   A copy of the License is located at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *   or in the "license" file accompanying this file. This file 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 com.amazon.opendistroforelasticsearch.sql.plugin;
+
+import com.amazon.opendistroforelasticsearch.sql.executor.format.ErrorMessageFactory;
+
+import com.amazon.opendistroforelasticsearch.sql.utils.LogUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.elasticsearch.ElasticsearchGenerationException;
+import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
+import org.elasticsearch.client.Requests;
+import org.elasticsearch.client.node.NodeClient;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.rest.BaseRestHandler;
+import org.elasticsearch.rest.BytesRestResponse;
+import org.elasticsearch.rest.RestController;
+import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import static org.elasticsearch.rest.RestStatus.INTERNAL_SERVER_ERROR;
+
+/**
+ * Interface to manage opendistro.sql.* cluster settings
+ * All non-sql settings are ignored.
+ * Any non-transient and non-persistent settings are ignored.
+ */
+public class RestSqlSettingsAction extends BaseRestHandler {
+    private static final Logger LOG = LogManager.getLogger(RestSqlSettingsAction.class);
+
+    private static final String PERSISTENT = "persistent";
+    private static final String TRANSIENT = "transient";
+    private static final String SQL_SETTINGS_PREFIX = "opendistro.sql.";
+
+    /**
+     * API endpoint path
+     */
+    public static final String SETTINGS_API_ENDPOINT = "/_opendistro/_sql/settings";
+
+    public RestSqlSettingsAction(Settings settings, RestController restController) {
+        super();
+        restController.registerHandler(RestRequest.Method.PUT, SETTINGS_API_ENDPOINT, this);
+    }
+
+    @Override
+    public String getName() {
+        return "sql_settings_action";
+    }
+
+    /**
+     * @see org.elasticsearch.rest.action.admin.cluster.RestClusterUpdateSettingsAction
+     */
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        LogUtils.addRequestId();
+        final ClusterUpdateSettingsRequest clusterUpdateSettingsRequest = Requests.clusterUpdateSettingsRequest();
+        clusterUpdateSettingsRequest.timeout(request.paramAsTime("timeout", clusterUpdateSettingsRequest.timeout()));
+        clusterUpdateSettingsRequest.masterNodeTimeout(
+                request.paramAsTime("master_timeout", clusterUpdateSettingsRequest.masterNodeTimeout()));
+        Map<String, Object> source;
+        try (XContentParser parser = request.contentParser()) {
+            source = parser.map();
+        }
+
+        try {
+            if (source.containsKey(TRANSIENT)) {
+                clusterUpdateSettingsRequest.transientSettings(getAndFilterSettings((Map) source.get(TRANSIENT)));
+            }
+            if (source.containsKey(PERSISTENT)) {
+                clusterUpdateSettingsRequest.persistentSettings(getAndFilterSettings((Map) source.get(PERSISTENT)));
+            }
+
+            return channel -> client.admin().cluster().updateSettings(
+                    clusterUpdateSettingsRequest, new RestToXContentListener<>(channel));
+        } catch (Exception e) {
+            LOG.error("Error changing OpenDistro SQL plugin cluster settings", e);
+            return channel -> channel.sendResponse(new BytesRestResponse(INTERNAL_SERVER_ERROR,
+                    ErrorMessageFactory.createErrorMessage(e, INTERNAL_SERVER_ERROR.getStatus()).toString()));
+        }
+    }
+
+    @Override
+    protected Set<String> responseParams() {
+        Set<String> responseParams = new HashSet<>(super.responseParams());
+        responseParams.addAll(Arrays.asList("sql", "flat", "separator", "_score", "_type", "_id", "newLine", "format"));
+        return responseParams;
+    }
+
+    private Settings getAndFilterSettings(Map<String, ?> source) {
+        try {
+            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            builder.map(source);
+            Settings.Builder settingsBuilder = Settings.builder().
+                    loadFromSource(Strings.toString(builder), builder.contentType());
+            settingsBuilder.keys().removeIf(key -> !key.startsWith(SQL_SETTINGS_PREFIX));
+            return settingsBuilder.build();
+        } catch (IOException e) {
+            throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
+        }
+    }
+}

src/main/java/com/amazon/opendistroforelasticsearch/sql/plugin/SqlPlug.java

@@ -78,7 +78,8 @@ public List<RestHandler> getRestHandlers(Settings settings, RestController restC
         Metrics.getInstance().registerDefaultMetrics();
         return Arrays.asList(
                 new RestSqlAction(settings, restController),
-                new RestSqlStatsAction(settings, restController));
+                new RestSqlStatsAction(settings, restController),
+                new RestSqlSettingsAction(settings, restController));
     }
 
     @Override

src/test/java/com/amazon/opendistroforelasticsearch/sql/doctest/core/builder/DocBuilder.java

@@ -193,7 +193,7 @@ default Requests put(String name, Object value) {
                 StringUtils.format("\"%s\": {\"%s\": \"%s\"}", "transient", name, value);
         return new Requests(
             restClient(),
-            new SqlRequest("PUT", "/_cluster/settings", new Body(setting).toString()),
+            new SqlRequest("PUT", "/_opendistro/_sql/settings", new Body(setting).toString()),
             null
         );
     }