Check for GM binary before run

lib/runner.js

@@ -2,8 +2,10 @@
 var EventEmitter = require('events').EventEmitter,
 
  q = require('q'),
+ exec = q.denodeify(require('child_process').exec),
  inherit = require('inherit'),
  promiseUtils = require('./promise-util'),
+ GeminiError = require('./gemini-error'),
 
  BrowserLauncher = require('./browser/launcher');
 
@@ -16,8 +18,11 @@ module.exports = inherit(EventEmitter, {
 
  runPlans: function(plans) {
  var _this = this;
- this.emit('begin');
- return q(this._prepare())
+ return this._checkGM()
+ .then(function() {
+ _this.emit('begin');
+ return q(_this._prepare());
+ })
  .then(function() {
  return promiseUtils.seqMap(plans, _this.runPlan.bind(_this));
  })
@@ -29,6 +34,20 @@ module.exports = inherit(EventEmitter, {
  _prepare: function() {
  },
 
+ _checkGM: function() {
+ return exec('gm -version')
+ .then(function() {
+ return true;
+ })
+ .fail(function() {
+ return q.reject(new GeminiError(
+ 'Unable to find required package: GraphicsMagick',
+ 'Make sure that GraphicsMagick is installed and availiable in your PATH.\n' +
+ 'Additonal info and installation instructions:\nhttp://www.graphicsmagick.org/'
+ ));
+ });
+ },
+
  runPlan: function(plan) {
  var _this = this,
  chains = plan.getChains();