handle non-existent (or empty) configurations

[tolitius]

handle non-existent (or empty) configurations

[tolitius]

Default Overrides

If you have a config.edn in your classpath, cprop will read it first.

You can then supply a -Dconf=/path/to/overrides.edn as you are starting the app.

For example in lein:

:profiles {:dev {;; ...
                 :jvm-opts ["-Dconf=dev-resources/dev-overrides.edn"]}

in boot:

(deftask dev []
  (System/setProperty "conf" "dev-resources/dev-overrides.edn")
  ;; ...)

This way when you call (load-config) it will first read the classpath for "common" props, and then will merge dev-overrides.edn on top of it.

ENV Overrides

Instead of -D you can also export ENV vars that would hierarchically match properties in the internal config.edn, and (load-config) will match them automatically, here is more docs about it.

Remote Overrides

You can also merge environment specific properties from Zookeep, etcd, Consul, etc.. For example this Consul client would take your config and would merge it with the values from Consul.

The Idea

The idea is to keep you code (i.e. (load-config.. )) environment agnostic and manage different environments with overrides from that environment, whether it is ENV, Consul, -D, etc.

[mbuczko]

thanks for so detailed answer. is config.edn hardcoded as a name for "base" configuration or is it also configurable somehow?

[tolitius]

config.edn is hardcoded as the default, but can be overwritten with :resource:

(load-config :resource "path/to/app.edn")

with all the above "overrides" strategies still apply.

[mbuczko]

great, that solves my problem :)