auto-retry download with master branch

a fallback download of the master branch is attempted only for unqualified
template names

lib/utils/template_generator.js

@@ -15,7 +15,29 @@ class TemplateGenerator {
     }
   }
 
-  downloadAndGenerate(uri, destinationFolder, name) {
+  download(url, tmpFilePath, browse) {
+    console.log(__('Installing template from ' + browse).green);
+    console.log(__('Downloading template...').green);
+    fs.mkdirpSync(utils.dirname(tmpFilePath));
+    return new Promise((resolve, reject) => {
+      utils.downloadFile(url, tmpFilePath, (err) => {
+        if (err) {
+          console.error(utils.errorMessage(err).red);
+          reject(err);
+        } else {
+          resolve();
+        }
+      });
+    });
+  }
+
+  downloadFailed() {
+    console.error('Does the template really exist?'.red);
+    console.error(`Embark's supported templates: https://embark.status.im/templates/`.green);
+    process.exit(1);
+  }
+
+  async downloadAndGenerate(uri, destinationFolder, name) {
     const fspath = utils.joinPath(destinationFolder, name);
     this.checkPathExists(fspath);
     const self = this;
@@ -28,27 +50,31 @@ class TemplateGenerator {
     }
     let {url, filePath, browse} = ext;
     let tmpFilePath = fs.tmpDir(filePath);
-    console.log(__('Installing template from ' + browse).green);
+    try {
-    console.log(__('Downloading template...').green);
+      try {
-
+        await this.download(url, tmpFilePath, browse);
-    fs.mkdirpSync(utils.dirname(tmpFilePath));
+      } catch (err) {
-    utils.downloadFile(url, tmpFilePath, (err) => {
+        let {url_fallback, filePath_fallback, browse_fallback} = ext;
-      if (err) {
+        if (url_fallback) {
-        console.error(utils.errorMessage(err).red);
+          console.log(__('Retrying with the master branch...').green);
-        console.error('Does the template really exist?'.red);
+          tmpFilePath = fs.tmpDir(filePath_fallback);
-        console.error(`Embark's supported templates: https://embark.status.im/templates/`.green);
+          await this.download(url_fallback, tmpFilePath, browse_fallback);
-        process.exit(1);
+        } else {
-      }
+          throw new Error();
-      utils.extractZip(tmpFilePath, fspath, {
-        map: file => {
-          let fixed_path = file.path.split('/');
-          fixed_path.shift(); // remove first directory
-          file.path = utils.joinPath(...fixed_path);
-          return file;
         }
-      }, () => {
+      }
-        self.installTemplate(fspath, name, true);
+    } catch (e) {
-      });
+      this.downloadFailed();
+    }
+    utils.extractZip(tmpFilePath, fspath, {
+      map: file => {
+        let fixed_path = file.path.split('/');
+        fixed_path.shift(); // remove first directory
+        file.path = utils.joinPath(...fixed_path);
+        return file;
+      }
+    }, () => {
+      self.installTemplate(fspath, name, true);
     });
   }
 
@@ -102,24 +128,36 @@ class TemplateGenerator {
 
   getExternalProject(uri) {
     let url, folder, hgi;
+    let fallback, url_fallback, folder_fallback, hgi_fallback;
     hgi = hostedGitInfo.fromUrl(uri);
     if (!hgi || hgi.user.includes('#')) {
       let templateAndBranch = uri.split('#');
       if (templateAndBranch.length === 1) {
+        fallback = true;
         let embarkVersion = semver(require('../../package.json').version);
         templateAndBranch.push(`${embarkVersion.major}.${embarkVersion.minor}`);
       }
       templateAndBranch[0] = `embark-framework/embark-${templateAndBranch[0]}-template`;
       hgi = hostedGitInfo.fromUrl(templateAndBranch.join('#'));
+      if (fallback) {
+        hgi_fallback = hostedGitInfo.fromUrl(templateAndBranch[0]);
+      }
     }
     if(!hgi) { throw new Error('Unsupported template name or git host URL'); }
     url = hgi.tarball();
     folder = `${hgi.user}/${hgi.project}/${hgi.committish || 'master'}`;
+    if (fallback) {
+      url_fallback = hgi_fallback.tarball();
+      folder_fallback = `${hgi_fallback.user}/${hgi_fallback.project}/master`;
+    }
 
     return {
       url,
       filePath: utils.joinPath(".embark/templates/", folder, "archive.zip"),
-      browse: decodeURIComponent(hgi.browse())
+      browse: decodeURIComponent(hgi.browse()),
+      url_fallback,
+      filePath_fallback: fallback && utils.joinPath(".embark/templates/", folder_fallback, "archive.zip"),
+      browse_fallback: fallback && decodeURIComponent(hgi_fallback.browse())
     };
   }
 }