Remove Q package dependency and add support for upcoming stackName property

.npmignore

@@ -19,3 +19,4 @@ logs
 node_modules
 pids
 results
+yarn.lock

lib/index.js

@@ -4,7 +4,6 @@ const AWS = require('aws-sdk');
 const diff = require('json-diff').diffString;
 const exec = require('child-process-promise').exec;
 const fs = require('fs-promise');
-const Q = require('q');
 
 class ServerlessPlugin {
   constructor(serverless, options) {
@@ -57,40 +56,44 @@ class ServerlessPlugin {
   }
 
   downloadTemplate() {
-    const deferred = Q.defer();
+    let stackName;
+
     const orgTemplate = this.options.orgTemplate;
+
+    if (this.serverless.service.provider
+        && typeof this.serverless.service.provider.stackName !== 'undefined'
+        && this.serverless.service.provider.stackName !== '') {
+      stackName = this.serverless.service.provider.stackName;
+    } else {
+      stackName = `${this.serverless.service.service}-${this.options.stage}`;
+    }
+
     const params = {
-      StackName: `${this.serverless.service.service}-${this.options.stage}`,
+      StackName: stackName,
       TemplateStage: 'Processed',
     };
 
     this.serverless.cli.log('Downloading currently deployed template');
 
-    this.cloudFormation.getTemplate(params, (err, data) => {
-      if (err) {
-        deferred.reject(err.message);
-      } else {
+    return this.cloudFormation.getTemplate(params).promise()
+      .then((data) => {
         let templateBody = JSON.parse(data.TemplateBody);
         templateBody = JSON.stringify(templateBody, null, 2);
 
-        fs.writeFile(orgTemplate, templateBody)
-          .then(() => deferred.resolve())
-          .catch(fsErr => deferred.reject(fsErr.message));
-      }
-    });
-
-    return deferred.promise;
+        return fs.writeFile(orgTemplate, templateBody)
+          .then(() => Promise.resolve());
+      })
+      .catch(err => Promise.reject(err.message));
   }
 
   diff() {
-    const deferred = Q.defer();
     const diffTool = this.options.diffTool;
     const localTemplate = this.options.localTemplate;
     const orgTemplate = this.options.orgTemplate;
 
     this.serverless.cli.log('Running diff against deployed template');
 
-    fs.stat(localTemplate)
+    return fs.stat(localTemplate)
       .then(() => {
         if (typeof diffTool === 'undefined') {
           const orgTemplateJson = JSON.parse(fs.readFileSync(orgTemplate, 'utf8'));
@@ -103,25 +106,23 @@ class ServerlessPlugin {
             console.log(differences);
           }
 
-          deferred.resolve(differences);
-        } else {
-          exec(`${diffTool} ${orgTemplate} ${localTemplate} || true`)
-            .then((result) => {
-              const diffData = result.stdout;
-              console.log(diffData);
-              deferred.resolve(diffData);
-            })
-            .catch(execErr => deferred.reject(execErr.message));
+          return Promise.resolve(differences);
         }
+
+        return exec(`${diffTool} ${orgTemplate} ${localTemplate} || true`)
+          .then((result) => {
+            const diffData = result.stdout;
+            console.log(diffData);
+            return Promise.resolve(diffData);
+          });
       })
       .catch((err) => {
         if (err.code === 'ENOENT') {
           const errorPrefix = `${localTemplate} could not be found:`;
-          deferred.reject(`${errorPrefix} run "sls deploy --noDeploy" first.`);
+          return Promise.reject(`${errorPrefix} run "sls deploy --noDeploy" first.`);
         }
+        return Promise.reject(err);
       });
-
-    return deferred.promise;
   }
 }