refactor: app.cluster auto bind this (#570)

lib/egg.js

@@ -57,6 +57,36 @@ class EggApplication extends EggCore {
 
  this[CLUSTER_CLIENTS] = [];
 
+ /**
+ * Wrap the Client with Leader/Follower Pattern
+ *
+ * @description almost the same as Agent.cluster API, the only different is that this method create Follower.
+ *
+ * @see https:/node-modules/cluster-client
+ * @param {Function} clientClass - client class function
+ * @param {Object} [options]
+ * - {Boolean} [autoGenerate] - whether generate delegate rule automatically, default is true
+ * - {Function} [formatKey] - a method to tranform the subscription info into a string，default is JSON.stringify
+ * - {Object} [transcode|JSON.stringify/parse]
+ * - {Function} encode - custom serialize method
+ * - {Function} decode - custom deserialize method
+ * - {Boolean} [isBroadcast] - whether broadcast subscrption result to all followers or just one, default is true
+ * - {Number} [responseTimeout] - response timeout, default is 3 seconds
+ * - {Number} [maxWaitTime|30000] - leader startup max time, default is 30 seconds
+ * @return {ClientWrapper} wrapper
+ */
+ this.cluster = (clientClass, options) => {
+ options = options || {};
+ // cluster need a port that can't conflict on the environment
+ options.port = this._options.clusterPort;
+ // agent worker is leader, app workers are follower
+ options.isLeader = this.type === 'agent';
+ options.logger = this.coreLogger;
+ const client = cluster(clientClass, options);
+ this._patchClusterClient(client);
+ return client;
+ };
+
  // register close function
  this.beforeClose(() => {
  for (const logger of this.loggers.values()) {
@@ -317,37 +347,6 @@ class EggApplication extends EggCore {
  singleton.init();
  }
 
-
- /**
- * Wrap the Client with Leader/Follower Pattern
- *
- * @description almost the same as Agent.cluster API, the only different is that this method create Follower.
- *
- * @see https:/node-modules/cluster-client
- * @param {Function} clientClass - client class function
- * @param {Object} [options]
- * - {Boolean} [autoGenerate] - whether generate delegate rule automatically, default is true
- * - {Function} [formatKey] - a method to tranform the subscription info into a string，default is JSON.stringify
- * - {Object} [transcode|JSON.stringify/parse]
- * - {Function} encode - custom serialize method
- * - {Function} decode - custom deserialize method
- * - {Boolean} [isBroadcast] - whether broadcast subscrption result to all followers or just one, default is true
- * - {Number} [responseTimeout] - response timeout, default is 3 seconds
- * - {Number} [maxWaitTime|30000] - leader startup max time, default is 30 seconds
- * @return {ClientWrapper} wrapper
- */
- cluster(clientClass, options) {
- options = options || {};
- // cluster need a port that can't conflict on the environment
- options.port = this._options.clusterPort;
- // agent worker is leader, app workers are follower
- options.isLeader = this.type === 'agent';
- options.logger = this.coreLogger;
- const client = cluster(clientClass, options);
- this._patchClusterClient(client);
- return client;
- }
-
  _patchClusterClient(client) {
  const create = client.create;
  client.create = (...args) => {

test/fixtures/apps/cluster_mod_app/app.js

@@ -6,7 +6,8 @@ module.exports = function(app) {
  const done = app.readyCallback('register_client', {
  isWeakDep: app.config.runMode === 0,
  });
- app.registryClient = app.cluster(RegistryClient).create();
+ const cluster = app.cluster;
+ app.registryClient = cluster(RegistryClient).create();
  app.registryClient.ready(done);
 
  app.registryClient.subscribe({