feat: #16 支持shardingKey 客户端实现

lib/message/message.js

@@ -148,6 +148,12 @@ class Message {
     return this.properties[MessageConst.SYSTEM_PROP_KEY_STARTDELIVERTIME] || 0;
   }
 
+  get shardingKey() {
+    return this.properties && this.properties[MessageConst.PROPERTY_SHARDING_KEY];
+  }
+  set shardingKey(val) {
+    this.properties[MessageConst.PROPERTY_SHARDING_KEY] = val;
+  }
 }
 
 module.exports = Message;

lib/message/message_const.js

@@ -18,6 +18,7 @@ exports.PROPERTY_PRODUCER_GROUP = 'PGROUP';
 exports.PROPERTY_MIN_OFFSET = 'MIN_OFFSET';
 exports.PROPERTY_MAX_OFFSET = 'MAX_OFFSET';
 exports.PROPERTY_BUYER_ID = 'BUYER_ID';
+exports.PROPERTY_SHARDING_KEY = '__SHARDING_KEY';
 exports.PROPERTY_ORIGIN_MESSAGE_ID = 'ORIGIN_MESSAGE_ID';
 exports.PROPERTY_TRANSFER_FLAG = 'TRANSFER_FLAG';
 exports.PROPERTY_CORRECTION_FLAG = 'CORRECTION_FLAG';

lib/producer/mq_producer.js

@@ -204,7 +204,7 @@ class MQProducer extends ClientConfig {
     let lastBrokerName;
     let sendResult;
     for (; times < timesTotal && Date.now() - beginTimestamp < maxTimeout; times++) {
-      const messageQueue = topicPublishInfo.selectOneMessageQueue(lastBrokerName);
+      const messageQueue = topicPublishInfo.selectOneMessageQueue(lastBrokerName, msg);
       if (!messageQueue) {
         continue;
       }

lib/producer/topic_publish_info.js

@@ -1,5 +1,7 @@
 'use strict';
 
+const crypto = require('crypto')
+
 class TopicPublishInfo {
   constructor() {
     this.orderTopic = false;
@@ -20,27 +22,46 @@ class TopicPublishInfo {
    * @param {String} lastBrokerName - last broker name
    * @return {Object} queue
    */
-  selectOneMessageQueue(lastBrokerName) {
+  selectOneMessageQueue(lastBrokerName, message) {
     let index,
       pos,
       mq;
-    if (lastBrokerName) {
-      index = this.sendWhichQueue++;
-      for (let i = 0, len = this.messageQueueList.length; i < len; i++) {
-        pos = Math.abs(index++) % len;
-        mq = this.messageQueueList[pos];
-        if (mq.brokerName !== lastBrokerName) {
-          return mq;
-        }
-      }
-      return null;
+
+    const shardingKey = message && message.shardingKey;
+    let queueId = '';
+    if (shardingKey) {
+      // 这里不应该是所有可用队列数字，应该是queue总数
+      // 但这里的 messageQueueList 是所有可写队列， golang和java客户端均为在queue总对恶劣中寻找位置
+      // 通过寻找所有可写queueId总数计算应该写入的queueId
+      const queueIds = [];
+      this.messageQueueList.forEach(queue => {
+        if (!queueIds.includes(queue.queueId)) queueIds.push(queue.queueId);
+      });
+
+      // 参考golang和java的sdk，没有规范确定的shardingKey找queueId的实现标准
+      // 若引入其他hash算法就显得比较笨重, 可以使用 nodejs 原生hash方法生成可计算的hash值
+      // Reference: https://github.com/apache/rocketmq/blob/c11ed78eeb73c23da4cf9a36a6bad493a1279210/proxy/src/main/java/org/apache/rocketmq/proxy/grpc/v2/producer/SendMessageActivity.java#L382
+      // Reference: https://github.com/apache/rocketmq-client-go/blob/896a8a3453be4bcfcb5bfb5bb9139c4df6d4cdab/producer/selector.go#L112
+      const queueIndex = crypto.createHash('md5').update(shardingKey).digest().readUInt32BE() % queueIds.length;
+      queueId = queueIds[queueIndex] || ''
     }
-    index = this.sendWhichQueue++;
+
     if (!Number.isSafeInteger(this.sendWhichQueue)) {
       this.sendWhichQueue = 0; // 超出安全范围，重置为 0
     }
-    pos = Math.abs(index) % this.messageQueueList.length;
-    return this.messageQueueList[pos];
+    index = this.sendWhichQueue++;
+    for (let i = 0, len = this.messageQueueList.length; i < len; i++) {
+      pos = Math.abs(index++) % len;
+      mq = this.messageQueueList[pos];
+      if (lastBrokerName && mq.brokerName === lastBrokerName) {
+        continue;
+      }
+      if (queueId && mq.queueId !== queueId) {
+        continue;
+      }
+      return mq;
+    }
+    return null;
   }
 }