video 36 - routes refresh

[jumarko]

I've been waiting for this for long so thanks a lot!

One little thing I've noticed - you are wrapping routes/routes in an anonymous function.
I just used routes/routes as is:

(defn cheffy-routes [service-map]
  (assoc service-map ::http/routes
         (if (dev? service-map)
           ;; notice they used #(routes/routes) instead
           routes/routes
           (routes/routes))))

Is there any difference in that? Will my code be less reloadable when using this approach?

It also was not obvious me, that you can simply use a function returning routes instead of actual data structure representing the routes.
I skimmed through http://pedestal.io/guides/defining-routes and http://pedestal.io/reference/index#_routing_and_linking but couldn't didn't find any mention of that.

[jacekschae]

Hey there,
Sorry I was away for a while, with Pedestal it's the bets to look at source code: https://github.com/pedestal/pedestal/blob/d20065013abf5d3793ae5301e18a2398707fa2a9/service/src/io/pedestal/http.clj#L191-L193

Did you try to reload the code without anonymous function? Does it really work without reloading the system?

[jumarko]

Thanks for the pointer - it can be tricky to find the right place to look at (in the source code) but yeah, default-interceptors sounds like a good place to check.

As far as I can remember, reloading it worked well without the anonymous function.

I had other problems with reloading, notably when you change some of the interceptors.
It's not a deal breaker but it might require reloading a few different places.
Concrete and tricky example is debugging (I use cider-debugger frequently) - let's say you want to debug transact! here: https://github.com/jumarko/learn-pedestal/blob/main/src/main/cheffy/interceptors.clj#L30

1. You need to instrument that function (that means cider will replace the function definition with a new function that installs breakpoints)
2. You then need to reload the definition of transact-interceptor (https://github.com/jumarko/learn-pedestal/blob/main/src/main/cheffy/interceptors.clj#L57-L60), but not the whole file because that would replace previous instrumentation
3. Then, you need to reload recipes routes to make sure the updated version of transact-interceptor is used.

So it kinda works but it's still cumbersome, especially if there's a few levels of indirection between in the routes implementation.