NAME

envopts - Clojure library for parsing configuration from environment

SYNOPSIS

  (ns your-ns.main
    (:require [nl.jomco.envopts :as envopts]))

  (def opt-specs {:port     ["port nr" :int :default 80]
                  :hostname ["hostname to use" :str]})

  (defn -main [& args]
    (let [[opts errs] (envopts/opts env opt-specs)]
      (when errs
        (println (envopts/errs-description errs))
        (System/exit 1))
      ... do something with opts))

DESCRIPTION

See the documentation on cljdoc.org and the inline docs.

ALPHA RELEASE

This library is in alpha; it works for us but we're still tweaking the interface.

RATIONALE

When running applications as services, it's useful to set configuration options using environment variables. The Twelve-Factor App section on configuration goes into more detail why.

Our preferred tool for reading the environment is Environ, which works well. When using Environ in production settings, we found some additional things missing; Types, Defaults and Reporting.

Types: In the environment, everything is a string, but the application configuration may need numbers, urls, uuids etc. envopts will parse the environment strings as the expected type - or fail with an error report.

Defaults: dealing with defaults can be a hassle - it's really easy to end up with settings defined everywhere.

Error reporting: when deploying an application, it's extremely useful to have clear and complete error feedback when the application is misconfigured.

OPTIONS SPEC

TODO

AUTHOR

Joost Diepenmaat joost@jomco.nl

SEE ALSO

https://12factor.net/ - The 12 Factor App manifesto

https://github.com/weavejester/environ - Environ