feat: get clusterPort

Closes eggjs/egg#219

Author: popomore

lib/master.js

@@ -8,6 +8,7 @@ const childprocess = require('child_process');
 const cfork = require('cfork');
 const ready = require('get-ready');
 const debug = require('debug')('egg-cluster');
+const detectPort = require('detect-port');
 const ConsoleLogger = require('egg-logger').EggConsoleLogger;
 
 const parseOptions = require('./utils/options');
@@ -77,7 +78,17 @@ class Master extends EventEmitter {
 
     this.onExit();
 
-    this.forkAgentWorker();
+    detectPort((err, port) => {
+      /* istanbul ignore if */
+      if (err) {
+        err.name = 'ClusterPortConflictError';
+        err.message = '[master] try get free port error, ' + err.message;
+        this.logger.error(err);
+        return;
+      }
+      this.options.clusterPort = port;
+      this.forkAgentWorker();
+    });
   }
 
   forkAgentWorker() {

package.json

@@ -34,6 +34,7 @@
     "cfork": "^1.6.0",
     "cluster-reload": "^1.0.2",
     "debug": "^2.4.5",
+    "detect-port": "^1.1.0",
     "egg-logger": "^1.5.0",
     "get-ready": "^1.0.0",
     "sendmessage": "^1.1.0"

test/master.test.js

@@ -22,6 +22,7 @@ describe('test/lib/cluster/master.test.js', () => {
 
       app.expect('stdout', /egg start/)
       .expect('stdout', /egg started/)
+      .expect('stdout', /\\"clusterPort\\":\d+/)
       .expect('code', 0)
       .end(done);
     });