Show download progress when restoring rsync backups

src/backups.js

@@ -229,14 +229,14 @@ function createReadStream(sourceFile, key) {
 
     stream.on('error', function (error) {
         debug('createReadStream: read stream error.', error);
-        ps.emit('error', new BoxError(BoxError.EXTERNAL_ERROR, error.message));
+        ps.emit('error', new BoxError(BoxError.FS_ERROR, error.message));
     });
 
     if (key !== null) {
         var encrypt = crypto.createCipher('aes-256-cbc', key);
         encrypt.on('error', function (error) {
             debug('createReadStream: encrypt stream error.', error);
-            ps.emit('error', new BoxError(BoxError.EXTERNAL_ERROR, error.message));
+            ps.emit('error', new BoxError(BoxError.CRYPTO_ERROR, error.message));
         });
         return stream.pipe(encrypt).pipe(ps);
     } else {
@@ -249,17 +249,25 @@ function createWriteStream(destFile, key) {
     assert(key === null || typeof key === 'string');
 
     var stream = fs.createWriteStream(destFile);
+    var ps = progressStream({ time: 10000 }); // display a progress every 10 seconds
+
+    stream.on('error', function (error) {
+        debug('createWriteStream: write stream error.', error);
+        ps.emit('error', new BoxError(BoxError.FS_ERROR, error.message));
+    });
 
     if (key !== null) {
         var decrypt = crypto.createDecipher('aes-256-cbc', key);
         decrypt.on('error', function (error) {
             debug('createWriteStream: decrypt stream error.', error);
+            ps.emit('error', new BoxError(BoxError.CRYPTO_ERROR, error.message));
         });
-        decrypt.pipe(stream);
-        return decrypt;
+        ps.pipe(decrypt).pipe(stream);
     } else {
-        return stream;
+        ps.pipe(stream);
     }
+
+    return ps;
 }
 
 function tarPack(dataLayout, key, callback) {
@@ -571,6 +579,12 @@ function downloadDir(backupConfig, backupFilePath, dataLayout, progressCallback,
             async.retry({ times: 5, interval: 20000 }, function (retryCallback) {
                 let destStream = createWriteStream(destFilePath, backupConfig.key || null);
 
+                destStream.on('progress', function (progress) {
+                    const transferred = Math.round(progress.transferred/1024/1024), speed = Math.round(progress.speed/1024/1024);
+                    if (!transferred && !speed) return progressCallback({ message: `Downloading ${entry.fullPath}` }); // 0M@0Mbps looks wrong
+                    progressCallback({ message: `Downloading ${entry.fullPath}: ${transferred}M@${speed}Mbps` });
+                });
+
                 // protect against multiple errors. must destroy the write stream so that a previous retry does not write
                 let closeAndRetry = once((error) => {
                     if (error) progressCallback({ message: `Download ${entry.fullPath} to ${destFilePath} errored: ${error.message}` });