fix: propagate trailer errors correctly

Author: dryajov

src/utils/send-files-stream.js

@@ -123,6 +123,8 @@ module.exports = (send, path) => {
         return retStream.push(null) // early
       }
 
+      response.on('error', (err) => retStream.emit('error', err))
+
       if (!isStream(response)) {
         retStream.push(response)
         retStream.push(null)

src/utils/send-request.js

@@ -33,7 +33,7 @@ function onRes (buffer, cb) {
     const stream = Boolean(res.headers['x-stream-output'])
     const chunkedObjects = Boolean(res.headers['x-chunked-output'])
     const isJson = res.headers['content-type'] &&
-                   res.headers['content-type'].indexOf('application/json') === 0
+      res.headers['content-type'].indexOf('application/json') === 0
 
     if (res.statusCode >= 400 || !res.statusCode) {
       return parseError(res, cb)
@@ -47,28 +47,16 @@ function onRes (buffer, cb) {
     // Return a stream of JSON objects
     if (chunkedObjects && isJson) {
       const outputStream = pump(res, ndjson.parse())
-      // TODO: This needs reworking.
-      // this is a chicken and egg problem -
-      // 1) we can't get Trailer headers unless the response ends
-      // 2) we can't propagate the error, because the response stream
-      // is closed
-      // (perhaps we can workaround this using pull-streams)
       res.on('end', () => {
         let err = res.trailers['x-stream-error']
         if (err) {
           // Not all errors are JSON
           try {
             err = JSON.parse(err)
           } catch (e) {
-            err = {
-              Code: 'n/a',
-              Message: err
-            }
+            err = { Message: err }
           }
-          const error = new Error(`Server responded with 500`)
-          error.code = err.Code
-          error.message = err.Message
-          outputStream.destroy(error) // error is not going to be propagated
+          outputStream.emit('error', new Error(err.Message))
         }
       })
       return cb(null, outputStream)