Application Configuration

The application configuration can be quite extensive. Because MonkeyCI is meant to be used locally as well as as a managed service, many parts of the application should be made configurable. The configuration can be passed in on several levels. These are, where later levels have priority over earlier:

1. Default (fallback) configuration, used when no other is available.
2. Global configuration, found in /etc/monkeyci/config.edn.
3. User configuration, read from ~/.monkeyci/config.edn.
4. Environment variables.
5. Command-line arguments.

Not all properties can be configured on the command-line, but the environment and files support all of them.

Global and user config

On the system and user level, configuration is located in an edn file. Json could also be supported, but for now the default is edn. This is because edn is Clojure-based, so it is more in-line with the inner application workings. But also because edn is more concise as json, you don't have to type as many double-quotes.

The configuration is hierarchical, like this:

{:http
 ;; Overwrite the http port for the web/api server
 {:port 3000}}

Configuration files are read using Aero, which allows to include other files, refer to other parts of the file, etc... You can also include environment variables.

Environment Variables

Environment variables are non-hierarchical and it turns out to be problematic. Originally a system was included to automatically map the hierarchy to the structured way as in the config file. But this results in many problems, e.g. with regards to typing. So currently environment variables are not directly supported. If they are needed, they can be referred to via the #env reader tag provided by Aero.

Command-line

The final possible way to set configuration is on the command line. This also has the highest priority, so it will override any previous config. Just run monkeyci -h to see all configuration parameters. They also depend on the command that's being issued. To override the http port on command line, you would do this:

$ monkeyci server -p 3000