What's the right way to include a browser REPL on a page, but only in development?

Question

I'm using Austin to set up a browser-connected REPL, and following the example of its sample project, which uses Enlive to add the REPL script to the page.

Now I'd like to deploy my app, but I don't wan't Austin or my REPL to be on the page in production. What's the intended way to use the REPL only in development?

Is there a way to use Enlive as a middleware I could use in development and not in production?

Answer 1

There's almost always something that uniquely distinguishes a production environment from :dev that you can use as a conditional: if in :dev, inject the result of (browser-connected-repl-js); if not, don't.

If your deployment environment doesn't have such a property, I'd suggest adding one, as this sort of "only in environment X" use case is pretty common for a lot of things.

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On the other hand, if you're looking to avoid having Austin and its dependencies included in your production-targeted builds entirely without changing any of your code that uses browser-connected-repl-js, one solution might be to simply dummy up the relevant Austin namespace, e.g.:

(ns cemerick.austin.repls)

(defn browser-connected-repl-js [& _] "")

Put that in cemerick/austin/repls.clj in a directory that is included in your project.clj's non-:dev profile:source-paths. Now your code will deploy to production without Austin and its dependencies, and your code will transparently call the above dummy function (injecting nothing into your page(s)).