test: eliminate multicast test FreeBSD flakiness

test-dgram-multicast-multi-process was flaky on FreeBSD and Raspeberry
Pi. This refactoring fixes the issue by eliminating a race condition.

Fixes: https://github.com/nodejs/node/issues/2474
PR-URL: https://github.com/nodejs/node/pull/4042
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

test/internet/test-dgram-multicast-multi-process.js

@@ -1,30 +1,122 @@
 'use strict';
-var common = require('../common'),
+const common = require('../common');
-    assert = require('assert'),
+const assert = require('assert');
-    dgram = require('dgram'),
+const dgram = require('dgram');
-    util = require('util'),
+const fork = require('child_process').fork;
-    Buffer = require('buffer').Buffer,
+const LOCAL_BROADCAST_HOST = '224.0.0.114';
-    fork = require('child_process').fork,
+const TIMEOUT = common.platformTimeout(5000);
-    LOCAL_BROADCAST_HOST = '224.0.0.114',
+const messages = [
-    TIMEOUT = common.platformTimeout(5000),
+  new Buffer('First message to send'),
-    messages = [
+  new Buffer('Second message to send'),
-      new Buffer('First message to send'),
+  new Buffer('Third message to send'),
-      new Buffer('Second message to send'),
+  new Buffer('Fourth message to send')
-      new Buffer('Third message to send'),
+];
-      new Buffer('Fourth message to send')
+const workers = {};
-    ];
+const listeners = 3;
+
+
+// Skip test in FreeBSD jails.
+if (common.inFreeBSDJail) {
+  console.log('1..0 # Skipped: In a FreeBSD jail');
+  return;
+}
+
+function launchChildProcess(index) {
+  const worker = fork(__filename, ['child']);
+  workers[worker.pid] = worker;
+
+  worker.messagesReceived = [];
+
+  // Handle the death of workers.
+  worker.on('exit', function(code, signal) {
+    // Don't consider this the true death if the worker has finished
+    // successfully or if the exit code is 0.
+    if (worker.isDone || code === 0) {
+      return;
+    }
+
+    dead += 1;
+    console.error('[PARENT] Worker %d died. %d dead of %d',
+                  worker.pid,
+                  dead,
+                  listeners);
+
+    if (dead === listeners) {
+      console.error('[PARENT] All workers have died.');
+      console.error('[PARENT] Fail');
+      process.exit(1);
+    }
+  });
+
+  worker.on('message', function(msg) {
+    if (msg.listening) {
+      listening += 1;
+
+      if (listening === listeners) {
+        // All child process are listening, so start sending.
+        sendSocket.sendNext();
+      }
+      return;
+    }
+    if (msg.message) {
+      worker.messagesReceived.push(msg.message);
+
+      if (worker.messagesReceived.length === messages.length) {
+        done += 1;
+        worker.isDone = true;
+        console.error('[PARENT] %d received %d messages total.',
+                      worker.pid,
+                      worker.messagesReceived.length);
+      }
+
+      if (done === listeners) {
+        console.error('[PARENT] All workers have received the ' +
+                      'required number of messages. Will now compare.');
+
+        Object.keys(workers).forEach(function(pid) {
+          const worker = workers[pid];
+
+          var count = 0;
+
+          worker.messagesReceived.forEach(function(buf) {
+            for (var i = 0; i < messages.length; ++i) {
+              if (buf.toString() === messages[i].toString()) {
+                count++;
+                break;
+              }
+            }
+          });
+
+          console.error('[PARENT] %d received %d matching messages.',
+                        worker.pid, count);
+
+          assert.strictEqual(count, messages.length,
+                       'A worker received an invalid multicast message');
+        });
+
+        clearTimeout(timer);
+        console.error('[PARENT] Success');
+        killChildren(workers);
+      }
+    }
+  });
+}
+
+function killChildren(children) {
+  Object.keys(children).forEach(function(key) {
+    const child = children[key];
+    child.kill();
+  });
+}
 
 if (process.argv[2] !== 'child') {
-  var workers = {},
+  var listening = 0;
-      listeners = 3,
+  var dead = 0;
-      listening = 0,
+  var i = 0;
-      dead = 0,
+  var done = 0;
-      i = 0,
+
-      done = 0,
+  // Exit the test if it doesn't succeed within TIMEOUT.
-      timer = null;
+  var timer = setTimeout(function() {
-
-  //exit the test if it doesn't succeed within TIMEOUT
-  timer = setTimeout(function() {
     console.error('[PARENT] Responses were not received within %d ms.',
                   TIMEOUT);
     console.error('[PARENT] Fail');
@@ -34,101 +126,18 @@ if (process.argv[2] !== 'child') {
     process.exit(1);
   }, TIMEOUT);
 
-  //launch child processes
+  // Launch child processes.
   for (var x = 0; x < listeners; x++) {
-    (function() {
+    launchChildProcess(x);
-      var worker = fork(process.argv[1], ['child']);
-      workers[worker.pid] = worker;
-
-      worker.messagesReceived = [];
-
-      //handle the death of workers
-      worker.on('exit', function(code, signal) {
-        // don't consider this the true death if the
-        // worker has finished successfully
-
-        // or if the exit code is 0
-        if (worker.isDone || code === 0) {
-          return;
-        }
-
-        dead += 1;
-        console.error('[PARENT] Worker %d died. %d dead of %d',
-                      worker.pid,
-                      dead,
-                      listeners);
-
-        if (dead === listeners) {
-          console.error('[PARENT] All workers have died.');
-          console.error('[PARENT] Fail');
-
-          killChildren(workers);
-
-          process.exit(1);
-        }
-      });
-
-      worker.on('message', function(msg) {
-        if (msg.listening) {
-          listening += 1;
-
-          if (listening === listeners) {
-            //all child process are listening, so start sending
-            sendSocket.sendNext();
-          }
-        }
-        else if (msg.message) {
-          worker.messagesReceived.push(msg.message);
-
-          if (worker.messagesReceived.length === messages.length) {
-            done += 1;
-            worker.isDone = true;
-            console.error('[PARENT] %d received %d messages total.',
-                          worker.pid,
-                          worker.messagesReceived.length);
-          }
-
-          if (done === listeners) {
-            console.error('[PARENT] All workers have received the ' +
-                          'required number of messages. Will now compare.');
-
-            Object.keys(workers).forEach(function(pid) {
-              var worker = workers[pid];
-
-              var count = 0;
-
-              worker.messagesReceived.forEach(function(buf) {
-                for (var i = 0; i < messages.length; ++i) {
-                  if (buf.toString() === messages[i].toString()) {
-                    count++;
-                    break;
-                  }
-                }
-              });
-
-              console.error('[PARENT] %d received %d matching messages.',
-                            worker.pid, count);
-
-              assert.equal(count, messages.length,
-                           'A worker received an invalid multicast message');
-            });
-
-            clearTimeout(timer);
-            console.error('[PARENT] Success');
-            killChildren(workers);
-          }
-        }
-      });
-    })(x);
   }
 
   var sendSocket = dgram.createSocket('udp4');
-  // FIXME a libuv limitation makes it necessary to bind()
+  // FIXME: a libuv limitation makes it necessary to bind()
-  // before calling any of the set*() functions - the bind()
+  // before calling any of the set*() functions. The bind()
-  // call is what creates the actual socket...
+  // call is what creates the actual socket.
   sendSocket.bind();
 
-  // The socket is actually created async now
+  // The socket is actually created async now.
   sendSocket.on('listening', function() {
     sendSocket.setTTL(1);
     sendSocket.setBroadcast(true);
@@ -141,7 +150,7 @@ if (process.argv[2] !== 'child') {
   });
 
   sendSocket.sendNext = function() {
-    var buf = messages[i++];
+    const buf = messages[i++];
 
     if (!buf) {
       try { sendSocket.close(); } catch (e) {}
@@ -151,61 +160,51 @@ if (process.argv[2] !== 'child') {
     sendSocket.send(buf, 0, buf.length,
                     common.PORT, LOCAL_BROADCAST_HOST, function(err) {
           if (err) throw err;
-          console.error('[PARENT] sent %s to %s:%s',
+          console.error('[PARENT] sent "%s" to %s:%s',
-                        util.inspect(buf.toString()),
+                        buf.toString(),
                         LOCAL_BROADCAST_HOST, common.PORT);
           process.nextTick(sendSocket.sendNext);
         });
   };
-
-  function killChildren(children) {
-    Object.keys(children).forEach(function(key) {
-      var child = children[key];
-      child.kill();
-    });
-  }
 }
 
 if (process.argv[2] === 'child') {
-  var receivedMessages = [];
+  const receivedMessages = [];
-  var listenSocket = dgram.createSocket({
+  const listenSocket = dgram.createSocket({
     type: 'udp4',
     reuseAddr: true
   });
 
-  listenSocket.on('message', function(buf, rinfo) {
+  listenSocket.on('listening', function() {
-    console.error('[CHILD] %s received %s from %j', process.pid,
+    listenSocket.addMembership(LOCAL_BROADCAST_HOST);
-                  util.inspect(buf.toString()), rinfo);
 
-    receivedMessages.push(buf);
+    listenSocket.on('message', function(buf, rinfo) {
+      console.error('[CHILD] %s received "%s" from %j', process.pid,
+                    buf.toString(), rinfo);
 
-    process.send({ message: buf.toString() });
+      receivedMessages.push(buf);
 
-    if (receivedMessages.length == messages.length) {
+      process.send({ message: buf.toString() });
-      // .dropMembership() not strictly needed but here as a sanity check
-      listenSocket.dropMembership(LOCAL_BROADCAST_HOST);
-      process.nextTick(function() {
-        listenSocket.close();
-      });
-    }
-  });
 
-  listenSocket.on('close', function() {
+      if (receivedMessages.length == messages.length) {
-    //HACK: Wait to exit the process to ensure that the parent
+        // .dropMembership() not strictly needed but here as a sanity check.
-    //process has had time to receive all messages via process.send()
+        listenSocket.dropMembership(LOCAL_BROADCAST_HOST);
-    //This may be indicitave of some other issue.
+        process.nextTick(function() {
-    setTimeout(function() {
+          listenSocket.close();
-      process.exit();
+        });
-    }, 1000);
+      }
-  });
+    });
 
-  listenSocket.on('listening', function() {
+    listenSocket.on('close', function() {
+      // HACK: Wait to exit the process to ensure that the parent
+      // process has had time to receive all messages via process.send()
+      // This may be indicative of some other issue.
+      setTimeout(function() {
+        process.exit();
+      }, common.platformTimeout(1000));
+    });
     process.send({ listening: true });
   });
 
   listenSocket.bind(common.PORT);
-
-  listenSocket.on('listening', function() {
-    listenSocket.addMembership(LOCAL_BROADCAST_HOST);
-  });
 }