process: Add exitCode property

This allows one to set a specific status code, while still letting the
process exit gracefully once all async operations are completed.

doc/api/process.markdown

@@ -233,6 +233,16 @@ To exit with a 'failure' code:
 The shell that executed node should see the exit code as 1.
 
 
+## process.exitCode
+
+A number which will be the process exit code, when the process either
+exits gracefully, or is exited via `process.exit()` without specifying
+a code.
+
+Specifying a code to `process.exit(code)` will override any previous
+setting of `process.exitCode`.
+
+
 ## process.getgid()
 
 Note: this function is only available on POSIX platforms (i.e. not Windows,

src/node.cc

@@ -3168,11 +3168,17 @@ void EmitExit(Environment* env) {
   Local<Object> process_object = env->process_object();
   process_object->Set(FIXED_ONE_BYTE_STRING(node_isolate, "_exiting"),
                       True(node_isolate));
+
+  Handle<String> exitCode = FIXED_ONE_BYTE_STRING(node_isolate, "exitCode");
+  int code = process_object->Get(exitCode)->IntegerValue();
+
   Local<Value> args[] = {
     FIXED_ONE_BYTE_STRING(node_isolate, "exit"),
-    Integer::New(0, node_isolate)
+    Integer::New(code, node_isolate)
   };
+
   MakeCallback(env, process_object, "emit", ARRAY_SIZE(args), args);
+  exit(code);
 }
 
 

src/node.js

@@ -545,12 +545,16 @@
   };
 
   startup.processKillAndExit = function() {
+    process.exitCode = 0;
     process.exit = function(code) {
+      if (NativeModule.require('util').isNumber(code))
+        process.exitCode = code;
+
       if (!process._exiting) {
         process._exiting = true;
-        process.emit('exit', code || 0);
+        process.emit('exit', process.exitCode || 0);
       }
-      process.reallyExit(code || 0);
+      process.reallyExit(process.exitCode || 0);
     };
 
     process.kill = function(pid, sig) {

test/simple/test-process-exit-code.js

@@ -0,0 +1,77 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+
+switch (process.argv[2]) {
+  case 'child1':
+    return child1();
+  case 'child2':
+    return child2();
+  case 'child3':
+    return child3();
+  case undefined:
+    return parent();
+  default:
+    throw new Error('wtf');
+}
+
+function child1() {
+  process.exitCode = 42;
+  process.on('exit', function(code) {
+    assert.equal(code, 42);
+  });
+}
+
+function child2() {
+  process.exitCode = 99;
+  process.on('exit', function(code) {
+    assert.equal(code, 42);
+  });
+  process.exit(42);
+}
+
+function child3() {
+  process.exitCode = 99;
+  process.on('exit', function(code) {
+    assert.equal(code, 0);
+  });
+  process.exit(0);
+}
+
+function parent() {
+  test('child1', 42);
+  test('child2', 42);
+  test('child3', 0);
+}
+
+function test(arg, exit) {
+  var spawn = require('child_process').spawn;
+  var node = process.execPath;
+  var f = __filename;
+  spawn(node, [f, arg], {stdio: 'inherit'}).on('exit', function(code) {
+    assert.equal(code, exit, 'wrong exit for ' +
+                 arg + '\nexpected:' + exit +
+                 ' but got:' + code);
+    console.log('ok - %s exited with %d', arg, exit);
+  });
+}