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var common = require('./common');
var _tempDir = require('./tempdir');
var _pwd = require('./pwd');
var path = require('path');
var fs = require('fs');
var child = require('child_process');
var DEFAULT_MAXBUFFER_SIZE = 20 * 1024 * 1024;
common.register('exec', _exec, {
unix: false,
canReceivePipe: true,
wrapOutput: false,
});
// Hack to run child_process.exec() synchronously (sync avoids callback hell)
// Uses a custom wait loop that checks for a flag file, created when the child process is done.
// (Can't do a wait loop that checks for internal Node variables/messages as
// Node is single-threaded; callbacks and other internal state changes are done in the
// event loop).
function execSync(cmd, opts, pipe) {
if (!common.config.execPath) {
common.error('Unable to find a path to the node binary. Please manually set config.execPath');
}
var tempDir = _tempDir();
var stdoutFile = path.resolve(tempDir + '/' + common.randomFileName());
var stderrFile = path.resolve(tempDir + '/' + common.randomFileName());
var codeFile = path.resolve(tempDir + '/' + common.randomFileName());
var scriptFile = path.resolve(tempDir + '/' + common.randomFileName());
var sleepFile = path.resolve(tempDir + '/' + common.randomFileName());
opts = common.extend({
silent: common.config.silent,
cwd: _pwd().toString(),
env: process.env,
maxBuffer: DEFAULT_MAXBUFFER_SIZE,
}, opts);
var previousStdoutContent = '';
var previousStderrContent = '';
// Echoes stdout and stderr changes from running process, if not silent
function updateStream(streamFile) {
if (opts.silent || !fs.existsSync(streamFile)) {
return;
}
var previousStreamContent;
var procStream;
if (streamFile === stdoutFile) {
previousStreamContent = previousStdoutContent;
procStream = process.stdout;
} else { // assume stderr
previousStreamContent = previousStderrContent;
procStream = process.stderr;
}
var streamContent = fs.readFileSync(streamFile, 'utf8');
// No changes since last time?
if (streamContent.length <= previousStreamContent.length) {
return;
}
procStream.write(streamContent.substr(previousStreamContent.length));
previousStreamContent = streamContent;
}
if (fs.existsSync(scriptFile)) common.unlinkSync(scriptFile);
if (fs.existsSync(stdoutFile)) common.unlinkSync(stdoutFile);
if (fs.existsSync(stderrFile)) common.unlinkSync(stderrFile);
if (fs.existsSync(codeFile)) common.unlinkSync(codeFile);
var execCommand = JSON.stringify(common.config.execPath) + ' ' + JSON.stringify(scriptFile);
var script;
opts.cwd = path.resolve(opts.cwd);
var optString = JSON.stringify(opts);
if (typeof child.execSync === 'function') {
script = [
"var child = require('child_process')",
" , fs = require('fs');",
'var childProcess = child.exec(' + JSON.stringify(cmd) + ', ' + optString + ', function(err) {',
' var fname = ' + JSON.stringify(codeFile) + ';',
' if (!err) {',
' fs.writeFileSync(fname, "0");',
' } else if (err.code === undefined) {',
' fs.writeFileSync(fname, "1");',
' } else {',
' fs.writeFileSync(fname, err.code.toString());',
' }',
'});',
'var stdoutStream = fs.createWriteStream(' + JSON.stringify(stdoutFile) + ');',
'var stderrStream = fs.createWriteStream(' + JSON.stringify(stderrFile) + ');',
'childProcess.stdout.pipe(stdoutStream, {end: false});',
'childProcess.stderr.pipe(stderrStream, {end: false});',
'childProcess.stdout.pipe(process.stdout);',
'childProcess.stderr.pipe(process.stderr);',
].join('\n') +
(pipe ? '\nchildProcess.stdin.end(' + JSON.stringify(pipe) + ');\n' : '\n') +
[
'var stdoutEnded = false, stderrEnded = false;',
'function tryClosingStdout(){ if(stdoutEnded){ stdoutStream.end(); } }',
'function tryClosingStderr(){ if(stderrEnded){ stderrStream.end(); } }',
"childProcess.stdout.on('end', function(){ stdoutEnded = true; tryClosingStdout(); });",
"childProcess.stderr.on('end', function(){ stderrEnded = true; tryClosingStderr(); });",
].join('\n');
fs.writeFileSync(scriptFile, script);
if (opts.silent) {
opts.stdio = 'ignore';
} else {
opts.stdio = [0, 1, 2];
}
// Welcome to the future
try {
child.execSync(execCommand, opts);
} catch (e) {
// Clean up immediately if we have an exception
try { common.unlinkSync(scriptFile); } catch (e2) {}
try { common.unlinkSync(stdoutFile); } catch (e2) {}
try { common.unlinkSync(stderrFile); } catch (e2) {}
try { common.unlinkSync(codeFile); } catch (e2) {}
throw e;
}
} else {
cmd += ' > ' + stdoutFile + ' 2> ' + stderrFile; // works on both win/unix
script = [
"var child = require('child_process')",
" , fs = require('fs');",
'var childProcess = child.exec(' + JSON.stringify(cmd) + ', ' + optString + ', function(err) {',
' var fname = ' + JSON.stringify(codeFile) + ';',
' if (!err) {',
' fs.writeFileSync(fname, "0");',
' } else if (err.code === undefined) {',
' fs.writeFileSync(fname, "1");',
' } else {',
' fs.writeFileSync(fname, err.code.toString());',
' }',
'});',
].join('\n') +
(pipe ? '\nchildProcess.stdin.end(' + JSON.stringify(pipe) + ');\n' : '\n');
fs.writeFileSync(scriptFile, script);
child.exec(execCommand, opts);
// The wait loop
// sleepFile is used as a dummy I/O op to mitigate unnecessary CPU usage
// (tried many I/O sync ops, writeFileSync() seems to be only one that is effective in reducing
// CPU usage, though apparently not so much on Windows)
while (!fs.existsSync(codeFile)) { updateStream(stdoutFile); fs.writeFileSync(sleepFile, 'a'); }
while (!fs.existsSync(stdoutFile)) { updateStream(stdoutFile); fs.writeFileSync(sleepFile, 'a'); }
while (!fs.existsSync(stderrFile)) { updateStream(stderrFile); fs.writeFileSync(sleepFile, 'a'); }
try { common.unlinkSync(sleepFile); } catch (e) {}
}
// At this point codeFile exists, but it's not necessarily flushed yet.
// Keep reading it until it is.
var code = parseInt('', 10);
while (isNaN(code)) {
code = parseInt(fs.readFileSync(codeFile, 'utf8'), 10);
}
var stdout = fs.readFileSync(stdoutFile, 'utf8');
var stderr = fs.readFileSync(stderrFile, 'utf8');
// No biggie if we can't erase the files now -- they're in a temp dir anyway
try { common.unlinkSync(scriptFile); } catch (e) {}
try { common.unlinkSync(stdoutFile); } catch (e) {}
try { common.unlinkSync(stderrFile); } catch (e) {}
try { common.unlinkSync(codeFile); } catch (e) {}
if (code !== 0) {
common.error('', code, { continue: true });
}
var obj = common.ShellString(stdout, stderr, code);
return obj;
} // execSync()
// Wrapper around exec() to enable echoing output to console in real time
function execAsync(cmd, opts, pipe, callback) {
var stdout = '';
var stderr = '';
opts = common.extend({
silent: common.config.silent,
cwd: _pwd().toString(),
env: process.env,
maxBuffer: DEFAULT_MAXBUFFER_SIZE,
}, opts);
var c = child.exec(cmd, opts, function (err) {
if (callback) {
if (!err) {
callback(0, stdout, stderr);
} else if (err.code === undefined) {
// See issue #536
callback(1, stdout, stderr);
} else {
callback(err.code, stdout, stderr);
}
}
});
if (pipe) c.stdin.end(pipe);
c.stdout.on('data', function (data) {
stdout += data;
if (!opts.silent) process.stdout.write(data);
});
c.stderr.on('data', function (data) {
stderr += data;
if (!opts.silent) process.stderr.write(data);
});
return c;
}
//@
//@ ### exec(command [, options] [, callback])
//@ Available options (all `false` by default):
//@
//@ + `async`: Asynchronous execution. If a callback is provided, it will be set to
//@ `true`, regardless of the passed value.
//@ + `silent`: Do not echo program output to console.
//@ + and any option available to Node.js's
//@ [child_process.exec()](https://nodejs.org/api/child_process.html#child_process_child_process_exec_command_options_callback)
//@
//@ Examples:
//@
//@ ```javascript
//@ var version = exec('node --version', {silent:true}).stdout;
//@
//@ var child = exec('some_long_running_process', {async:true});
//@ child.stdout.on('data', function(data) {
//@ /* ... do something with data ... */
//@ });
//@
//@ exec('some_long_running_process', function(code, stdout, stderr) {
//@ console.log('Exit code:', code);
//@ console.log('Program output:', stdout);
//@ console.log('Program stderr:', stderr);
//@ });
//@ ```
//@
//@ Executes the given `command` _synchronously_, unless otherwise specified. When in synchronous
//@ mode, this returns a ShellString (compatible with ShellJS v0.6.x, which returns an object
//@ of the form `{ code:..., stdout:... , stderr:... }`). Otherwise, this returns the child process
//@ object, and the `callback` gets the arguments `(code, stdout, stderr)`.
//@
//@ Not seeing the behavior you want? `exec()` runs everything through `sh`
//@ by default (or `cmd.exe` on Windows), which differs from `bash`. If you
//@ need bash-specific behavior, try out the `{shell: 'path/to/bash'}` option.
//@
//@ **Note:** For long-lived processes, it's best to run `exec()` asynchronously as
//@ the current synchronous implementation uses a lot of CPU. This should be getting
//@ fixed soon.
function _exec(command, options, callback) {
options = options || {};
if (!command) common.error('must specify command');
var pipe = common.readFromPipe();
// Callback is defined instead of options.
if (typeof options === 'function') {
callback = options;
options = { async: true };
}
// Callback is defined with options.
if (typeof options === 'object' && typeof callback === 'function') {
options.async = true;
}
options = common.extend({
silent: common.config.silent,
async: false,
}, options);
try {
if (options.async) {
return execAsync(command, options, pipe, callback);
} else {
return execSync(command, options, pipe);
}
} catch (e) {
common.error('internal error');
}
}
module.exports = _exec;
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