Duct Main

A tool for running applications built with the Duct framework.

Note that this tool is currently experimental, and most available Duct components will not work with this yet.

Installation

Add the following dependency and alias to your deps.edn file:

{:deps {org.duct-framework/main {:mvn/version "0.1.4"}}
 :aliases {:duct {:main-opts ["-m" "duct.main"]}}}

Then run:

clojure -M:duct --init

This will create a minimal duct.edn file.

Configuration

Duct Main uses a configuration file, duct.edn, located at the root of your repository. Like deps.edn, it is a map, and it has two valid keys:

• :system - an Integrant configuration map
• :vars - a map of variables to bind to the configuration map

For example:

{:vars
 {port {:type :int, :env PORT, :arg port, :default 3000}
  name {:type :str, :arg name, :default "World"}}

 :system
 {:example.handler/hello
  {:name #ig/var name}

  :duct.server.http/jetty
  {:port    #ig/var port
   :handler #ig/ref :example.handler/hello}}}

Vars

Vars are how we get information into the system from external sources. Currently there are two available sources: environment variables and command-line flags.

Vars are symbols, and their value is defined by a map with the following keys:

• :arg - the command-line flag to get the var from
• :default - the default value of the var
• :env - the environment variable to get the var from
• :type - the type of the var, one of: :str, :int

Vars can also be defined through Integrant's annotations. When Duct starts, it looks through the keys in the configuration for annotations with the key :duct/vars.

Command line

You can run your Duct application with:

clojure -M:duct --main

And you can start a development REPL with:

clojure -M:duct --repl

For more information on the Duct tool, run:

clojure -M:duct --help

It's also recommended that you create a shell alias to make these commands briefer:

alias duct="clojure -M:duct"

License

Copyright © 2024 James Reeves

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.