Execute git submodule foreach... in parallel! Useful for PrestaShop development :)

foreach_submodule.js

#!/usr/bin/nodejs

var fs    = require('fs');
var spawn = require('child_process').spawn;

function parseSubmodules(data) {

	var lines = data.split(/\n+/);
	var modules = {};
	var currentPath;

	for (var l = 0, length = lines.length; l < length; l++) {

		var line = lines[l].trim();

		if (!line) {
			continue;
		}

		var match;

		if ((match = line.match(/\[submodule\s+"(.*?)"\]/))) {
			currentPath = match[1];
			modules[currentPath] = {};
		} else {
			var kv = line.split(/\s*=\s*/);
			modules[currentPath][kv[0]] = kv[1];
		}
	}

	return modules;
}

if (!fs.existsSync('.gitmodules'))
{
	console.log('No submodules found, aborting.');
	process.exit();
}

var modules = parseSubmodules(fs.readFileSync('.gitmodules', 'UTF-8'));

var args = process.argv.slice(2);

if (args.length === 0)
{
	console.log('No command specified, aborting.');
	process.exit();
}

var command        = args[0];

var errors = [];

if (command === '--init') {
	var initModule = function (module, next) {
		var cloneArgs = ['clone', module.data.url];
		if (module.data.branch) {
			cloneArgs.push('-b', module.data.branch);
		}
		cloneArgs.push('--recursive', module.path);

		var error = '';

		spawn('git', cloneArgs).on('close', function (code) {
			if (code === 0) {
				console.log('Successfully initialized submodule in `' + module.path + '`');
			} else {
				errors.push('Could not initialize submodule in `' + module.path + '`, failed with code ' + code + ' (' + error + ').');
			}

			if (next) {
				next();
			}
		}).stderr.on('data', function (chunk) {
			chunk = chunk.toString();
			if (chunk) {
				error += chunk;
			}
		});
	};

	var processBatch = function (modules) {

		if (modules.length > 0) {
			initModule(modules.shift(), function () {
				processBatch(modules);
			});
		}
	};

	var modulesList = [];

	var path;
	
	for (path in modules) {
		if (Object.prototype.hasOwnProperty.call(modules, path)) {
			var data = modules[path];
			modulesList.push({
				path: path,
				data: data
			});
		}
	}

	modulesList.sort(function (a, b) {
		return a.path < b.path ? -1 : 1;
	});


	var moduleBatches = [];
	var currentBatch = [];
	var currentTopLevel;

	for (var i = 0, len = modulesList.length; i < len; ++i) {
		var submodule = modulesList[i];
		var topLevel = submodule.path.split('/')[0];
		if (topLevel !== currentTopLevel && currentBatch.length > 0) {
			moduleBatches.push(currentBatch);
			currentBatch = [];
		}
		currentTopLevel = topLevel;
		currentBatch.push(submodule);
	}
	if (currentBatch.length > 0) {
		moduleBatches.push(currentBatch);
	}

	for (var m = 0, mlen = moduleBatches.length; m < mlen; ++m) {
		processBatch(moduleBatches[m]);
	}
} else {
	var spawnArguments = args.slice(1);
	console.log('Will run: ', command + ' ' + spawnArguments.join(' '));
	for (path in modules) {
		if (modules.hasOwnProperty(path)) {
			(function(path){
				spawn(command, spawnArguments, {cwd: path}).on('close', function (code) {
					if (code === 0) {
						console.log('Successfully ran command in submodule `' + path + '`.');
					} else {
						errors.push('Command failed with code ' + code + ' in submodule `' + path + '`.');
					}
				});
			})(path);
		}
	}
}

process.on('exit', function () {
	if (errors.length === 0)
	{
		console.log("\nDone!");
	}
	else
	{
		console.log("\nDone, but there are errors:");
		console.log(errors.join("\n"));
	}
});