"fastbootMiddleware is not a function"

We’re seeing this error from time to time when switching branches while leaving ember s running. I haven’t digged deeper into it but though I’d open this as a heads up already.

Stacktrace:

TypeError: fastbootMiddleware is not a function
    at app.use (/Users/<Redacted>/Projets/mweb/node_modules/ember-cli-fastboot/index.js:256:11)
    at Layer.handle [as handle_request] (/Users/<Redacted>/Projets/mweb/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/Users/<Redacted>/Projets/mweb/node_modules/express/lib/router/index.js:312:13)
    at /Users/<Redacted>/Projets/mweb/node_modules/express/lib/router/index.js:280:7
    at Function.process_params (/Users/<Redacted>/Projets/mweb/node_modules/express/lib/router/index.js:330:12)
    at next (/Users/<Redacted>/Projets/mweb/node_modules/express/lib/router/index.js:271:10)
    at err (/Users/<Redacted>/Projets/mweb/node_modules/ember-cli/lib/tasks/server/middleware/broccoli-watcher/index.js:54:11)
    at watcher.then (/Users/<Redacted>/Projets/mweb/node_modules/broccoli-middleware/lib/watcher-middleware.js:35:7)
    at tryCatch (/Users/<Redacted>/Projets/mweb/node_modules/rsvp/dist/lib/rsvp/-internal.js:215:12)
    at invokeCallback (/Users/<Redacted>/Projets/mweb/node_modules/rsvp/dist/lib/rsvp/-internal.js:230:13)
    at /Users/<Redacted>/Projets/mweb/node_modules/rsvp/dist/lib/rsvp/then.js:29:16
    at flush (/Users/<Redacted>/Projets/mweb/node_modules/rsvp/dist/lib/rsvp/asap.js:85:5)
    at _combinedTickCallback (internal/process/next_tick.js:73:7)
    at process._tickDomainCallback (internal/process/next_tick.js:128:9)

Update

By looking at the code it’s pretty clear when this would happen (this.fastboot being false here resulting in undefined(req, resp, next) here), I’m just not sure what the scenario is in which that could be the case.

I’m not sure if something like this would make sense?

if (!this.fastboot || !this.fastbootMiddleware) {
  // TODO(future): make this configurable for allowing apps to pass sandboxGlobals
  // and custom sandbox class
  this.ui.writeLine(chalk.green('App is being served by FastBoot'));
  this.fastboot = new FastBoot({
    distPath: outputPath
  });

  this.fastbootMiddleware = FastBootExpressMiddleware({
    fastboot: this.fastboot
  });
}

this.fastbootMiddleware(req, resp, next);

[kratiahuja]

Cool, I’ll revert and release today

[marcoow]

I was able to reproduce the error. I added some logging to https://github.com/ember-fastboot/ember-cli-fastboot/blob/master/index.js#L243:

console.log('debug', this.fastboot, fastbootMiddleware);
if (!this.fastboot) {
  …

When the error occurs, this.fastboot is defined so that the if block is not entered but fastbootMiddleware is undefined. Thus, reverting #427 would actually fix this bug.