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src: add -r/--require flags for preloading modules
-r/--require can be used to preload modules on node startup. The option takes a single module name. The option can be repeated as necessary to preload multiple modules. This patch allows 'vendors' (such a cloud host) to inject functionality that gets executed at application startup without requiring an explicit require from the user's application. This can be useful to load vendor specific application monitoring APIs transparently. PR-URL: #881 Reviewed-By: Trevor Norris <trev.norris@gmail.com> Reviewed-By: Chris Dickinson <christopher.s.dickinson@gmail.com>
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-65
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7 files changed

+194
-65
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‎doc/iojs.1

+2
Original file line numberDiff line numberDiff line change
@@ -52,6 +52,8 @@ and servers.
5252
-i, --interactive always enter the REPL even if stdin
5353
does not appear to be a terminal
5454

55+
-r, --require module to preload at startup
56+
5557
--no-deprecation silence deprecation warnings
5658

5759
--trace-deprecation show stack traces on deprecations

‎src/node.cc

+37
Original file line numberDiff line numberDiff line change
@@ -114,6 +114,8 @@ static bool trace_deprecation = false;
114114
static bool throw_deprecation = false;
115115
static bool abort_on_uncaught_exception = false;
116116
static const char* eval_string = nullptr;
117+
static unsigned int preload_module_count = 0;
118+
static const char** preload_modules = nullptr;
117119
static bool use_debug_agent = false;
118120
static bool debug_wait_connect = false;
119121
static int debug_port = 5858;
@@ -2765,6 +2767,19 @@ void SetupProcessObject(Environment* env,
27652767
READONLY_PROPERTY(process, "_forceRepl", True(env->isolate()));
27662768
}
27672769

2770+
if (preload_module_count) {
2771+
CHECK(preload_modules);
2772+
Local<Array> array = Array::New(env->isolate());
2773+
for (unsigned int i = 0; i < preload_module_count; ++i) {
2774+
Local<String> module = String::NewFromUtf8(env->isolate(),
2775+
preload_modules[i]);
2776+
array->Set(i, module);
2777+
}
2778+
READONLY_PROPERTY(process,
2779+
"_preload_modules",
2780+
array);
2781+
}
2782+
27682783
// --no-deprecation
27692784
if (no_deprecation) {
27702785
READONLY_PROPERTY(process, "noDeprecation", True(env->isolate()));
@@ -2989,6 +3004,7 @@ static void PrintHelp() {
29893004
" -p, --print evaluate script and print result\n"
29903005
" -i, --interactive always enter the REPL even if stdin\n"
29913006
" does not appear to be a terminal\n"
3007+
" -r, --require module to preload (option can be repeated)\n"
29923008
" --no-deprecation silence deprecation warnings\n"
29933009
" --throw-deprecation throw an exception anytime a deprecated "
29943010
"function is used\n"
@@ -3046,11 +3062,13 @@ static void ParseArgs(int* argc,
30463062
const char** new_exec_argv = new const char*[nargs];
30473063
const char** new_v8_argv = new const char*[nargs];
30483064
const char** new_argv = new const char*[nargs];
3065+
const char** local_preload_modules = new const char*[nargs];
30493066

30503067
for (unsigned int i = 0; i < nargs; ++i) {
30513068
new_exec_argv[i] = nullptr;
30523069
new_v8_argv[i] = nullptr;
30533070
new_argv[i] = nullptr;
3071+
local_preload_modules[i] = nullptr;
30543072
}
30553073

30563074
// exec_argv starts with the first option, the other two start with argv[0].
@@ -3099,6 +3117,15 @@ static void ParseArgs(int* argc,
30993117
eval_string += 1;
31003118
}
31013119
}
3120+
} else if (strcmp(arg, "--require") == 0 ||
3121+
strcmp(arg, "-r") == 0) {
3122+
const char* module = argv[index + 1];
3123+
if (module == nullptr) {
3124+
fprintf(stderr, "%s: %s requires an argument\n", argv[0], arg);
3125+
exit(9);
3126+
}
3127+
args_consumed += 1;
3128+
local_preload_modules[preload_module_count++] = module;
31023129
} else if (strcmp(arg, "--interactive") == 0 || strcmp(arg, "-i") == 0) {
31033130
force_repl = true;
31043131
} else if (strcmp(arg, "--no-deprecation") == 0) {
@@ -3145,6 +3172,16 @@ static void ParseArgs(int* argc,
31453172
memcpy(argv, new_argv, new_argc * sizeof(*argv));
31463173
delete[] new_argv;
31473174
*argc = static_cast<int>(new_argc);
3175+
3176+
// Copy the preload_modules from the local array to an appropriately sized
3177+
// global array.
3178+
if (preload_module_count > 0) {
3179+
CHECK(!preload_modules);
3180+
preload_modules = new const char*[preload_module_count];
3181+
memcpy(preload_modules, local_preload_modules,
3182+
preload_module_count * sizeof(*preload_modules));
3183+
}
3184+
delete[] local_preload_modules;
31483185
}
31493186

31503187

‎src/node.js

+77-65
Original file line numberDiff line numberDiff line change
@@ -68,84 +68,96 @@
6868
var d = NativeModule.require('_debug_agent');
6969
d.start();
7070

71-
} else if (process._eval != null) {
72-
// User passed '-e' or '--eval' arguments to Node.
73-
evalScript('[eval]');
74-
} else if (process.argv[1]) {
75-
// make process.argv[1] into a full path
76-
var path = NativeModule.require('path');
77-
process.argv[1] = path.resolve(process.argv[1]);
78-
79-
// If this is a worker in cluster mode, start up the communication
80-
// channel.
81-
if (process.env.NODE_UNIQUE_ID) {
82-
var cluster = NativeModule.require('cluster');
83-
cluster._setupWorker();
71+
} else {
72+
// There is user code to be run
8473

85-
// Make sure it's not accidentally inherited by child processes.
86-
delete process.env.NODE_UNIQUE_ID;
74+
// Load any preload modules
75+
if (process._preload_modules) {
76+
var Module = NativeModule.require('module');
77+
process._preload_modules.forEach(function(module) {
78+
Module._load(module);
79+
});
8780
}
8881

89-
var Module = NativeModule.require('module');
82+
if (process._eval != null) {
83+
// User passed '-e' or '--eval' arguments to Node.
84+
evalScript('[eval]');
85+
} else if (process.argv[1]) {
86+
// make process.argv[1] into a full path
87+
var path = NativeModule.require('path');
88+
process.argv[1] = path.resolve(process.argv[1]);
89+
90+
// If this is a worker in cluster mode, start up the communication
91+
// channel.
92+
if (process.env.NODE_UNIQUE_ID) {
93+
var cluster = NativeModule.require('cluster');
94+
cluster._setupWorker();
95+
96+
// Make sure it's not accidentally inherited by child processes.
97+
delete process.env.NODE_UNIQUE_ID;
98+
}
9099

91-
if (global.v8debug &&
92-
process.execArgv.some(function(arg) {
93-
return arg.match(/^--debug-brk(=[0-9]*)?$/);
94-
})) {
100+
var Module = NativeModule.require('module');
95101

96-
// XXX Fix this terrible hack!
97-
//
98-
// Give the client program a few ticks to connect.
99-
// Otherwise, there's a race condition where `node debug foo.js`
100-
// will not be able to connect in time to catch the first
101-
// breakpoint message on line 1.
102-
//
103-
// A better fix would be to somehow get a message from the
104-
// global.v8debug object about a connection, and runMain when
105-
// that occurs. --isaacs
102+
if (global.v8debug &&
103+
process.execArgv.some(function(arg) {
104+
return arg.match(/^--debug-brk(=[0-9]*)?$/);
105+
})) {
106106

107-
var debugTimeout = +process.env.NODE_DEBUG_TIMEOUT || 50;
108-
setTimeout(Module.runMain, debugTimeout);
107+
// XXX Fix this terrible hack!
108+
//
109+
// Give the client program a few ticks to connect.
110+
// Otherwise, there's a race condition where `node debug foo.js`
111+
// will not be able to connect in time to catch the first
112+
// breakpoint message on line 1.
113+
//
114+
// A better fix would be to somehow get a message from the
115+
// global.v8debug object about a connection, and runMain when
116+
// that occurs. --isaacs
109117

110-
} else {
111-
// Main entry point into most programs:
112-
Module.runMain();
113-
}
118+
var debugTimeout = +process.env.NODE_DEBUG_TIMEOUT || 50;
119+
setTimeout(Module.runMain, debugTimeout);
114120

115-
} else {
116-
var Module = NativeModule.require('module');
117-
118-
// If -i or --interactive were passed, or stdin is a TTY.
119-
if (process._forceRepl || NativeModule.require('tty').isatty(0)) {
120-
// REPL
121-
var opts = {
122-
useGlobal: true,
123-
ignoreUndefined: false
124-
};
125-
if (parseInt(process.env['NODE_NO_READLINE'], 10)) {
126-
opts.terminal = false;
127-
}
128-
if (parseInt(process.env['NODE_DISABLE_COLORS'], 10)) {
129-
opts.useColors = false;
121+
} else {
122+
// Main entry point into most programs:
123+
Module.runMain();
130124
}
131-
var repl = Module.requireRepl().start(opts);
132-
repl.on('exit', function() {
133-
process.exit();
134-
});
135125

136126
} else {
137-
// Read all of stdin - execute it.
138-
process.stdin.setEncoding('utf8');
127+
var Module = NativeModule.require('module');
128+
129+
// If -i or --interactive were passed, or stdin is a TTY.
130+
if (process._forceRepl || NativeModule.require('tty').isatty(0)) {
131+
// REPL
132+
var opts = {
133+
useGlobal: true,
134+
ignoreUndefined: false
135+
};
136+
if (parseInt(process.env['NODE_NO_READLINE'], 10)) {
137+
opts.terminal = false;
138+
}
139+
if (parseInt(process.env['NODE_DISABLE_COLORS'], 10)) {
140+
opts.useColors = false;
141+
}
142+
var repl = Module.requireRepl().start(opts);
143+
repl.on('exit', function() {
144+
process.exit();
145+
});
139146

140-
var code = '';
141-
process.stdin.on('data', function(d) {
142-
code += d;
143-
});
147+
} else {
148+
// Read all of stdin - execute it.
149+
process.stdin.setEncoding('utf8');
144150

145-
process.stdin.on('end', function() {
146-
process._eval = code;
147-
evalScript('[stdin]');
148-
});
151+
var code = '';
152+
process.stdin.on('data', function(d) {
153+
code += d;
154+
});
155+
156+
process.stdin.on('end', function() {
157+
process._eval = code;
158+
evalScript('[stdin]');
159+
});
160+
}
149161
}
150162
}
151163
}

‎test/fixtures/printA.js

+1
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
1+
console.log('A')

‎test/fixtures/printB.js

+1
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
1+
console.log('B')

‎test/fixtures/printC.js

+1
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
1+
console.log('C')

‎test/parallel/test-preload.js

+75
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,75 @@
1+
var common = require('../common'),
2+
assert = require('assert'),
3+
path = require('path'),
4+
child_process = require('child_process');
5+
6+
var nodeBinary = process.argv[0];
7+
8+
var preloadOption = function(preloads) {
9+
var option = '';
10+
preloads.forEach(function(preload, index) {
11+
// TODO: randomly pick -r or --require
12+
option += '-r ' + preload + ' ';
13+
});
14+
return option;
15+
}
16+
17+
var fixture = function(name) {
18+
return path.join(__dirname, '../fixtures/' + name);
19+
}
20+
21+
var fixtureA = fixture('printA.js');
22+
var fixtureB = fixture('printB.js');
23+
var fixtureC = fixture('printC.js')
24+
var fixtureThrows = fixture('throws_error4.js');
25+
26+
// test preloading a single module works
27+
child_process.exec(nodeBinary + ' '
28+
+ preloadOption([fixtureA]) + ' '
29+
+ fixtureB,
30+
function(err, stdout, stderr) {
31+
if (err) throw err;
32+
assert.equal(stdout, 'A\nB\n');
33+
});
34+
35+
// test preloading multiple modules works
36+
child_process.exec(nodeBinary + ' '
37+
+ preloadOption([fixtureA, fixtureB]) + ' '
38+
+ fixtureC,
39+
function(err, stdout, stderr) {
40+
if (err) throw err;
41+
assert.equal(stdout, 'A\nB\nC\n');
42+
});
43+
44+
// test that preloading a throwing module aborts
45+
child_process.exec(nodeBinary + ' '
46+
+ preloadOption([fixtureA, fixtureThrows]) + ' '
47+
+ fixtureB,
48+
function(err, stdout, stderr) {
49+
if (err) {
50+
assert.equal(stdout, 'A\n');
51+
} else {
52+
throw new Error('Preload should have failed');
53+
}
54+
});
55+
56+
// test that preload can be used with --eval
57+
child_process.exec(nodeBinary + ' '
58+
+ preloadOption([fixtureA])
59+
+ '-e \'console.log("hello");\'',
60+
function(err, stdout, stderr) {
61+
if (err) throw err;
62+
assert.equal(stdout, 'A\nhello\n');
63+
});
64+
65+
// test that preload placement at other points in the cmdline
66+
// also test that duplicated preload only gets loaded once
67+
child_process.exec(nodeBinary + ' '
68+
+ preloadOption([fixtureA])
69+
+ '-e \'console.log("hello");\' '
70+
+ preloadOption([fixtureA, fixtureB]),
71+
function(err, stdout, stderr) {
72+
if (err) throw err;
73+
assert.equal(stdout, 'A\nB\nhello\n');
74+
});
75+

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