async some functions

lib/core/fs.js

@@ -53,6 +53,10 @@ function existsSync() {
   return fs.existsSync.apply(fs.existsSync, arguments);
 }
 
+function access() {
+  return fs.access.apply(fs.access, arguments);
+}
+
 function removeSync() {
   return fs.removeSync.apply(fs.removeSync, arguments);
 }
@@ -81,6 +85,7 @@ module.exports = {
   writeFileSync,
   readJSONSync,
   writeJSONSync,
+  access,
   existsSync,
   removeSync,
   embarkPath,

lib/pipeline/pipeline.js

@@ -129,20 +129,39 @@ class Pipeline {
                 function changeCwdBack(next) {
                   process.chdir(realCwd);
                   next();
+                },
+
+                function checkFile(next) {
+                  fs.access('./.embark/' + file.filename, (err) => {
+                    if (err) {
+                      self.log("couldn't find file: " + file.filename);
+                      return next("couldn't find file: " + file.filename);
+                    }
+                    next();
+                  });
+                },
+
+                function readFile(next) {
+                  fs.readFile('./.embark/' + file.filename, (err, data) => {
+                    if (err) {
+                      return next(err);
+                    }
+                    next(null, data.toString());
+                  });
+                },
+
+                function runPluginsOnContent(fileContent, next) {
+                  self.runPlugins(file, fileContent, next);
                 }
 
-              ], function(err, _result) {
+              ], function(err, contentFile) {
                 if (err) {
                   process.chdir(realCwd);
                   self.log(err);
                   return fileCb(err);
                 }
-                if (!fs.existsSync('./.embark/' + file.filename)) {
+
-                  self.log("couldn't find file: " + file.filename);
+                fileCb(null, contentFile);
-                  return fileCb("couldn't find file: " + file.filename);
-                }
-                let fileContent = fs.readFileSync('./.embark/' + file.filename).toString();
-                self.runPlugins(file, fileContent, fileCb);
               });
             } else {
               file.content(function(fileContent) {