source: Dev/trunk/grunt-tasks/heroku.js

var _ = require('underscore')
  , path = require('path');

module.exports = function(grunt) {
    
    grunt.registerTask(
        'heroku-config',
        "Get config values from heroku app and put them in grunt.config.",
        function(){
            var done = this.async();
            var options = this.options({
                keys: [],
                output: 'herokuConfig'
            });
            if ( !options.app ) {
                done(new Error(("Must specify the app name.")));
            } else {
                if ( options.keys.length === 0 ) {
                    grunt.log.warn("Did not specify any config keys.");
                }
                var tasks = _.map(options.keys, function(key){
                    return _.partial(getConfigValue,options.app,key);
                });
                grunt.util.async.series(tasks,function(error,results){
                    if ( error ) {
                        done(error);
                    } else {
                        var herokuConfig = {};
                        _.each(results,function(result){
                            _.extend(herokuConfig,result);
                        });
                        grunt.config.set(options.output,herokuConfig);
                        done();
                    }
                });
            }
        });

    function getConfigValue(app,key,callback) {
        grunt.util.spawn({
            cmd: 'heroku',
            args: ['config:get',key,'--app',app]
        }, function(error,result){
            if ( error ) {
                callback(error);
            } else {
                var value = grunt.util.normalizelf(result.stdout)
                            .split(grunt.util.linefeed)[0];
                result = {};
                result[key] = value;
                callback(null,result);
            }
        });
    }

    grunt.registerMultiTask(
        'foreman',
        "Run a foreman command in a directory.",
        function(){
            var options = this.options({
                cmd: 'start',
                cwd: '.'
            });
            var done = this.async();
            grunt.util.spawn({
                cmd: 'foreman',
                args: [options.cmd],
                opts: {
                    cwd: options.cwd,
                    stdio: 'inherit'
                }
            }, done);
        });

};