feat(poolCluster): add query method

Author: yuxizhe

lib/pool_cluster.js

@@ -4,6 +4,7 @@ const process = require('process');
 
 const Pool = require('./pool.js');
 const PoolConfig = require('./pool_config.js');
+const Connection = require('./connection.js');
 const EventEmitter = require('events').EventEmitter;
 
 /**
@@ -46,6 +47,43 @@ class PoolNamespace {
     });
   }
 
+  /**
+   * pool cluster query
+   * @param {*} sql
+   * @param {*} values
+   * @param {*} cb
+   * @returns query
+   */
+  query(sql, values, cb) {
+    const clusterNode = this._getClusterNode();
+    const query = Connection.createQuery(sql, values, cb, {});
+    if (clusterNode === null) {
+      return cb(new Error('Pool does Not exists.'));
+    }
+    this._cluster._getConnection(clusterNode, (err, conn) => {
+      if (err) {
+        if (typeof query.onResult === 'function') {
+          query.onResult(err);
+        } else {
+          query.emit('error', err);
+        }
+        return;
+      }
+      if (conn === 'retry') {
+        return this.query(sql, values, cb);
+      }
+      try {
+        conn.query(query).once('end', () => {
+          conn.release();
+        });
+      } catch (e) {
+        conn.release();
+        throw e;
+      }
+    });
+    return query;
+  }
+
   _getClusterNode() {
     const foundNodeIds = this._cluster._findNodeIds(this._pattern);
     if (foundNodeIds.length === 0) {