debugger, cluster: each worker has new debug port

Implement support for debugging cluster workers. Each worker process
is assigned a new debug port in an increasing sequence.

I.e. when master process uses port 5858, then worker 1 uses port 5859,
worker 2 uses port 5860, and so on.

Introduce new command-line parameter '--debug-port=' which sets debug_port
but does not start debugger. This option works for all node processes, it
is not specific to cluster workers.

Fixes joyent/node#5318.

1 files changed, 27 insertions, 1 deletions

diff --git a/lib/cluster.js b/lib/cluster.js
index 6503cb5f90..45b1224eb0 100644
--- a/lib/cluster.js
+++ b/lib/cluster.js
@@ -59,6 +59,25 @@ else
   workerInit();
 
 
+function createWorkerExecArgv(masterExecArgv, worker) {
+  var args = masterExecArgv.slice();
+  var debugPort = process.debugPort + worker.id;
+  var hasDebugArg = false;
+
+  for (var i = 0; i < args.length; i++) {
+    var match = args[i].match(/^(--debug|--debug-brk)(=\d+)?$/);
+    if (!match) continue;
+    args[i] = match[1] + '=' + debugPort;
+    hasDebugArg = true;
+  }
+
+  if (!hasDebugArg)
+    args = ['--debug-port=' + debugPort].concat(args);
+
+  return args;
+}
+
+
 function masterInit() {
   cluster.workers = {};
 
@@ -93,6 +112,13 @@ function masterInit() {
       settings.execArgv = settings.execArgv.concat(['--logfile=v8-%p.log']);
     }
     cluster.settings = settings;
+
+    process.on('internalMessage', function(message) {
+      if (message.cmd !== 'NODE_DEBUG_ENABLED') return;
+      for (key in cluster.workers)
+        process._debugProcess(cluster.workers[key].process.pid);
+    });
+
     cluster.emit('setup');
   };
 
@@ -107,7 +133,7 @@ function masterInit() {
     worker.process = fork(settings.exec, settings.args, {
       env: workerEnv,
       silent: settings.silent,
-      execArgv: settings.execArgv
+      execArgv: createWorkerExecArgv(settings.execArgv, worker)
     });
     worker.process.once('exit', function(exitCode, signalCode) {
       worker.suicide = !!worker.suicide;