Capra

Capra is a dependency manager and package repository for the Clojure programming language.

Using Capra

To use it, add capra.jar to your classpath, and include this line in your user.clj file:

(require 'capra)

Once you've done this, you can declare dependencies in the metadata for your namespace, and the dependencies will be automatically downloaded and added to the classpath at runtime.

For example:

(ns #^{:deps ("weavejester/hello-world/1.0")}
  example-app
  (:use weavejester.hello-world))

(hello-world)

If you have Capra set up, the "weavejester/hello-world/1.0" package will be downloaded and installed when you run the script.

If you do not have Capra installed, this script will still run, but you will have to manually download and add the "hello-world" package to the classpath. This means that people don't have to have Capra installed to use your Capra-enabled script.

Uploading packages to Capra

Uploading packages to Capra is also very straightforward. Open up a Clojure REPL and register a Capra account with a username and email address

user=> (require 'capra.account)
user=> (capra.account/register "jbloggs" "jbloggs@example.com")

You now have a Capra account. The passkey is generated randomly, and stored in $CAPRA_HOME/account.keys. The environmental variable CAPRA_HOME defaults to $HOME/.capra if not explicitly defined.

You can now upload a new package. Here is an example:

user=> (require 'capra.package)
user=> (capra.package/create
         {:account "jbloggs"
          :name "hello-world"
          :version "1.0"
          :files ["/home/jbloggs/hello-world.jar"]})

People can now access your package at "jbloggs/hello-world/1.0". You can include it in the metadata of any script.

Querying the repository

There are currently a few basic ways to query the Capra repository.

The capra.account/list function returns a set of all accounts registered in the repository:

user=> (capra.account/list)
#{"jbloggs", "weavejester"}

The capra.account/get function returns the public account data:

user=> (capra.account/get "jbloggs")
{:name "jbloggs"
 :email "jbloggs@example.com"
 :packages {"hello-world" {:name "hello-world"
                           :version "1.0"}}}

You can get more information from a particular package with capra.package/get:

user=> (capra.package/get "jbloggs/hello-world/1.0")     
{:account "jbloggs"
 :name "hello-world"
 :version "1.0"
 :files ({:href "http://capra.s3.amazonaws.com/xxxxxxxxxxx"
          :sha1 "xxxxxxxxxxxxxx"})}

You can then install this package explicitly by using capra.package/install:

user=> (capra.package/install "jbloggs/hello-world/1.0")
user=> (use 'jbloggs.hello-world)
user=> (hello-world)
Hello World