src: command line option to preload modules

doc/iojs.1

@@ -52,6 +52,8 @@ and servers.
   -i, --interactive      always enter the REPL even if stdin
                          does not appear to be a terminal
 
+  -r, --require          module to preload at startup
+
   --no-deprecation       silence deprecation warnings
 
   --trace-deprecation    show stack traces on deprecations

src/node.cc

@@ -114,6 +114,8 @@ static bool trace_deprecation = false;
 static bool throw_deprecation = false;
 static bool abort_on_uncaught_exception = false;
 static const char* eval_string = nullptr;
+static unsigned int preload_module_count = 0;
+static const char** preload_modules = nullptr;
 static bool use_debug_agent = false;
 static bool debug_wait_connect = false;
 static int debug_port = 5858;
@@ -2766,6 +2768,19 @@ void SetupProcessObject(Environment* env,
     READONLY_PROPERTY(process, "_forceRepl", True(env->isolate()));
   }
 
+  if (preload_module_count) {
+    CHECK(preload_modules);
+    Local<Array> array = Array::New(env->isolate());
+    for (unsigned int i = 0; i < preload_module_count; ++i) {
+      Local<String> module = String::NewFromUtf8(env->isolate(),
+                                                 preload_modules[i]);
+      array->Set(i, module);
+    }
+    READONLY_PROPERTY(process,
+                      "_preload_modules",
+                      array);
+  }
+
   // --no-deprecation
   if (no_deprecation) {
     READONLY_PROPERTY(process, "noDeprecation", True(env->isolate()));
@@ -2990,6 +3005,7 @@ static void PrintHelp() {
          "  -p, --print          evaluate script and print result\n"
          "  -i, --interactive    always enter the REPL even if stdin\n"
          "                       does not appear to be a terminal\n"
+         "  -r, --require        module to preload (option can be repeated)\n"
          "  --no-deprecation     silence deprecation warnings\n"
          "  --throw-deprecation  throw an exception anytime a deprecated "
          "function is used\n"
@@ -3045,11 +3061,13 @@ static void ParseArgs(int* argc,
   const char** new_exec_argv = new const char*[nargs];
   const char** new_v8_argv = new const char*[nargs];
   const char** new_argv = new const char*[nargs];
+  const char** local_preload_modules = new const char*[nargs];
 
   for (unsigned int i = 0; i < nargs; ++i) {
     new_exec_argv[i] = nullptr;
     new_v8_argv[i] = nullptr;
     new_argv[i] = nullptr;
+    local_preload_modules[i] = nullptr;
   }
 
   // exec_argv starts with the first option, the other two start with argv[0].
@@ -3098,6 +3116,15 @@ static void ParseArgs(int* argc,
           eval_string += 1;
         }
       }
+    } else if (strcmp(arg, "--require") == 0 ||
+               strcmp(arg, "-r") == 0) {
+      const char* module = argv[index + 1];
+      if (module == nullptr) {
+        fprintf(stderr, "%s: %s requires an argument\n", argv[0], arg);
+        exit(9);
+      }
+      args_consumed += 1;
+      local_preload_modules[preload_module_count++] = module;
     } else if (strcmp(arg, "--interactive") == 0 || strcmp(arg, "-i") == 0) {
       force_repl = true;
     } else if (strcmp(arg, "--no-deprecation") == 0) {
@@ -3144,6 +3171,16 @@ static void ParseArgs(int* argc,
   memcpy(argv, new_argv, new_argc * sizeof(*argv));
   delete[] new_argv;
   *argc = static_cast<int>(new_argc);
+
+  // Copy the preload_modules from the local array to an appropriately sized
+  // global array.
+  if (preload_module_count > 0) {
+    CHECK(!preload_modules);
+    preload_modules = new const char*[preload_module_count];
+    memcpy(preload_modules, local_preload_modules,
+           preload_module_count * sizeof(*preload_modules));
+  }
+  delete[] local_preload_modules;
 }
 
 

src/node.js

@@ -68,84 +68,96 @@
       var d = NativeModule.require('_debug_agent');
       d.start();
 
-    } else if (process._eval != null) {
-      // User passed '-e' or '--eval' arguments to Node.
-      evalScript('[eval]');
-    } else if (process.argv[1]) {
-      // make process.argv[1] into a full path
-      var path = NativeModule.require('path');
-      process.argv[1] = path.resolve(process.argv[1]);
-
-      // If this is a worker in cluster mode, start up the communication
-      // channel.
-      if (process.env.NODE_UNIQUE_ID) {
-        var cluster = NativeModule.require('cluster');
-        cluster._setupWorker();
+    } else {
+      // There is user code to be run
 
-        // Make sure it's not accidentally inherited by child processes.
-        delete process.env.NODE_UNIQUE_ID;
+      // Load any preload modules
+      if (process._preload_modules) {
+        var Module = NativeModule.require('module');
+        process._preload_modules.forEach(function(module) {
+          Module._load(module);
+        });
       }
 
-      var Module = NativeModule.require('module');
+      if (process._eval != null) {
+        // User passed '-e' or '--eval' arguments to Node.
+        evalScript('[eval]');
+      } else if (process.argv[1]) {
+        // make process.argv[1] into a full path
+        var path = NativeModule.require('path');
+        process.argv[1] = path.resolve(process.argv[1]);
+
+        // If this is a worker in cluster mode, start up the communication
+        // channel.
+        if (process.env.NODE_UNIQUE_ID) {
+          var cluster = NativeModule.require('cluster');
+          cluster._setupWorker();
+
+          // Make sure it's not accidentally inherited by child processes.
+          delete process.env.NODE_UNIQUE_ID;
+        }
 
-      if (global.v8debug &&
-          process.execArgv.some(function(arg) {
-            return arg.match(/^--debug-brk(=[0-9]*)?$/);
-          })) {
+        var Module = NativeModule.require('module');
 
-        // XXX Fix this terrible hack!
-        //
-        // Give the client program a few ticks to connect.
-        // Otherwise, there's a race condition where `node debug foo.js`
-        // will not be able to connect in time to catch the first
-        // breakpoint message on line 1.
-        //
-        // A better fix would be to somehow get a message from the
-        // global.v8debug object about a connection, and runMain when
-        // that occurs.  --isaacs
+        if (global.v8debug &&
+            process.execArgv.some(function(arg) {
+              return arg.match(/^--debug-brk(=[0-9]*)?$/);
+            })) {
 
-        var debugTimeout = +process.env.NODE_DEBUG_TIMEOUT || 50;
-        setTimeout(Module.runMain, debugTimeout);
+          // XXX Fix this terrible hack!
+          //
+          // Give the client program a few ticks to connect.
+          // Otherwise, there's a race condition where `node debug foo.js`
+          // will not be able to connect in time to catch the first
+          // breakpoint message on line 1.
+          //
+          // A better fix would be to somehow get a message from the
+          // global.v8debug object about a connection, and runMain when
+          // that occurs.  --isaacs
 
-      } else {
-        // Main entry point into most programs:
-        Module.runMain();
-      }
+          var debugTimeout = +process.env.NODE_DEBUG_TIMEOUT || 50;
+          setTimeout(Module.runMain, debugTimeout);
 
-    } else {
-      var Module = NativeModule.require('module');
-
-      // If -i or --interactive were passed, or stdin is a TTY.
-      if (process._forceRepl || NativeModule.require('tty').isatty(0)) {
-        // REPL
-        var opts = {
-          useGlobal: true,
-          ignoreUndefined: false
-        };
-        if (parseInt(process.env['NODE_NO_READLINE'], 10)) {
-          opts.terminal = false;
-        }
-        if (parseInt(process.env['NODE_DISABLE_COLORS'], 10)) {
-          opts.useColors = false;
+        } else {
+          // Main entry point into most programs:
+          Module.runMain();
         }
-        var repl = Module.requireRepl().start(opts);
-        repl.on('exit', function() {
-          process.exit();
-        });
 
       } else {
-        // Read all of stdin - execute it.
-        process.stdin.setEncoding('utf8');
+        var Module = NativeModule.require('module');
+
+        // If -i or --interactive were passed, or stdin is a TTY.
+        if (process._forceRepl || NativeModule.require('tty').isatty(0)) {
+          // REPL
+          var opts = {
+            useGlobal: true,
+            ignoreUndefined: false
+          };
+          if (parseInt(process.env['NODE_NO_READLINE'], 10)) {
+            opts.terminal = false;
+          }
+          if (parseInt(process.env['NODE_DISABLE_COLORS'], 10)) {
+            opts.useColors = false;
+          }
+          var repl = Module.requireRepl().start(opts);
+          repl.on('exit', function() {
+            process.exit();
+          });
 
-        var code = '';
-        process.stdin.on('data', function(d) {
-          code += d;
-        });
+        } else {
+          // Read all of stdin - execute it.
+          process.stdin.setEncoding('utf8');
 
-        process.stdin.on('end', function() {
-          process._eval = code;
-          evalScript('[stdin]');
-        });
+          var code = '';
+          process.stdin.on('data', function(d) {
+            code += d;
+          });
+
+          process.stdin.on('end', function() {
+            process._eval = code;
+            evalScript('[stdin]');
+          });
+        }
       }
     }
   }

test/fixtures/printA.js

@@ -0,0 +1 @@
+console.log('A')

test/fixtures/printB.js

@@ -0,0 +1 @@
+console.log('B')

test/fixtures/printC.js

@@ -0,0 +1 @@
+console.log('C')

test/parallel/test-preload.js

@@ -0,0 +1,75 @@
+var common = require('../common'),
+    assert = require('assert'),
+    path = require('path'),
+    child_process = require('child_process');
+
+var nodeBinary = process.argv[0];
+
+var preloadOption = function(preloads) {
+  var option = '';
+  preloads.forEach(function(preload, index) {
+    // TODO: randomly pick -r or --require
+    option += '-r ' + preload + ' ';
+  });
+  return option;
+}
+
+var fixture = function(name) {
+  return path.join(__dirname, '../fixtures/' + name);
+}
+
+var fixtureA = fixture('printA.js');
+var fixtureB = fixture('printB.js');
+var fixtureC = fixture('printC.js')
+var fixtureThrows = fixture('throws_error4.js');
+
+// test preloading a single module works
+child_process.exec(nodeBinary + ' '
+  + preloadOption([fixtureA]) + ' '
+  + fixtureB,
+  function(err, stdout, stderr) {
+    if (err) throw err;
+    assert.equal(stdout, 'A\nB\n');
+  });
+
+// test preloading multiple modules works
+child_process.exec(nodeBinary + ' '
+  + preloadOption([fixtureA, fixtureB]) + ' '
+  + fixtureC,
+  function(err, stdout, stderr) {
+    if (err) throw err;
+    assert.equal(stdout, 'A\nB\nC\n');
+  });
+
+// test that preloading a throwing module aborts
+child_process.exec(nodeBinary + ' '
+  + preloadOption([fixtureA, fixtureThrows]) + ' '
+  + fixtureB,
+  function(err, stdout, stderr) {
+    if (err) {
+      assert.equal(stdout, 'A\n');
+    } else {
+      throw new Error('Preload should have failed');
+    }
+  });
+
+// test that preload can be used with --eval
+child_process.exec(nodeBinary + ' '
+  + preloadOption([fixtureA])
+  + '-e "console.log(\'hello\');"',
+  function(err, stdout, stderr) {
+    if (err) throw err;
+    assert.equal(stdout, 'A\nhello\n');
+  });
+
+// test that preload placement at other points in the cmdline
+// also test that duplicated preload only gets loaded once
+child_process.exec(nodeBinary + ' '
+  + preloadOption([fixtureA])
+  + '-e "console.log(\'hello\');" '
+  + preloadOption([fixtureA, fixtureB]),
+  function(err, stdout, stderr) {
+    if (err) throw err;
+    assert.equal(stdout, 'A\nB\nhello\n');
+  });
+