Feature request: fallback connections

[daveyarwood]

Conjure continues to be excellent, but I've noticed one minor pain point: there is no way for me to configure Conjure to use its own prepl whenever I don't have mine running.

I like that there is a default behavior where, if you don't have any connections configured in a conjure.edn in your project or home config directory, Conjure will fall back to using its own prepl so that you still get some good basic functionality. If I don't have a ~/.config/conjure/conjure.edn file, I can edit a one-off Clojure file (i.e. vim /tmp/foo.clj) and automatically get docstrings for Clojure core functions, evaluate forms, and so on.

The trouble is that I do have a ~/.config/conjure/conjure.edn in my home directory for general things that I want available everywhere, like a :cwd connection that connects to a prepl server that I've started in the current directory on a port specified in a .socket-port file. Because I have that, if I go to edit a one-off file like /tmp/foo.clj, Conjure fails to connect to the :cwd connection (because I haven't bothered to start a prepl server in /tmp) and I'm left with no active connections. I think it would be great if there were some way that I could still get the fallback Conjure prepl behavior in the scenario.

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A couple of ideas:

1. We could consider this always being the fallback behavior when all of your connections fail to connect. Although, you would probably want to know that that's happening, so a warning would be in order, like you mentioned in Evaluate in Conjure's JVM by default #31.

2. We could go the explicit route and add an optional configuration key like :fallback, where you could specify another connection to use in the event that this one fails. Assuming the Conjure prepl has a publicly usable connection name like :conjure, then my :cwd connection config could look like: {:port #slurp-edn ".socket-port", :fallback :conjure}.

Either way, the idea is that when I run vim /tmp/foo.clj, once Conjure starts up, I see a warning that Conjure can't connect to :cwd, and it's using :conjure as a fallback.

[Olical]

Good idea! I think I worried about this a little when I was sorting out the inheritance of config files 🤔 I think I like the idea of just doing it automatically with a warning the most but I'll sleep on it 😄

[Olical]

Released in v1.0.0 🎉 😄