Deploying Clojure libraries to gitlab maven repository

05 June 2021

Gitlab provides an amazing package manager which supports most types of the package registries like npm, pypi, maven, etc. You can use this to manage your clojure private packages. Gitlab have an amazing documentation but it doesn't provide any docs on how to deploy clojure packages. We are going to look how to deploy a simple clojure package to gitlab private repository. We will be using leiningen for creating, managing and deploying clojure projects.

Creating a new clojure library

leiningen provides an easy way to create a clojure library project.

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lein new <library-name>

This create a simple clojure library with a project.clj configuration file and core.clj file. Update the description, url etc. for the package in your project.clj file.

Setting up gitlab deploy configuration

To deploy the package for your terminal you will need a gitlab personal or deploy token. You can generate a personal token using this documentation. If you are going with a deploy token make sure it have read_package_registry and write_package_registry scopes attached to it. To generate deploy token follow this documentation. Another thing you will need is the project id. You can get it from the repository home page below the repo name.

Once you have a gitlab personal or deploy token you have to set this to your project.clj file. leiningen provides a way to set package deploy configuration for each of the release type. You can add :repositories key in project.clj with the config values. So your project.clj will look like this.

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(defproject my-package "0.1.0-SNAPSHOT"
  :description "<description>"
  :url "<repo_url>"
  :license {:name "EPL-2.0"
            :url "https://www.eclipse.org/legal/epl-2.0/"}
  :dependencies [[org.clojure/clojure "1.10.0"]]
  :repl-options {:init-ns my-package.core}
  :repositories [["releases"  {:url           "https://gitlab.com/api/v4/projects/<project-id>/packages/maven"
                               :username      "Private-Token"
                               :password      "<personal | deploy token>"}
                                    "snapshots" {:url           "https://gitlab.com/api/v4/projects/<project-id>/packages/maven"
                               :username      "Private-Token"
                               :password      "<personal | deploy token>"}]])

You will need to add two configurations to the :repositories field. The snapshots config will be used for snapshot release and the releases config will be used for the major releases.

Deploying the package

It is time to deploy your package to gitlab. Run the lein deploy command.

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lein deploy

This will deploy the packages to gitlab package registry. You can see it by going to the repo page and selecting Package Registry from the Packages & Registries tab in the sidebar.

Securing the deploy tokens

In the last step we have hardcoded the personal or deploy token in the project.clj but for an actual project it is not secure to hardcode some credentials in a file we add to git. To secure it we can set an environment variable with the token and load that in our project.clj.

To pull the token from an environment variable to the project.clj we can use (System/getenv) function. By replacing the token with this function, the project.clj will look like

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:repositories [["releases"  {:url           "https://gitlab.com/api/v4/projects/<project-id>/packages/maven"
                             :username      "Private-Token"
                             :password      ~(System/getenv "GITLAB_DEPLOY_TOKEN")}
                              "snapshots" {:url           "https://gitlab.com/api/v4/projects/<project-id>/packages/maven"
                             :username      "Private-Token"
                             :password      ~(System/getenv "GITLAB_DEPLOY_TOKEN")}]]

Now we have a clojure package deployed to gitlab package registry. Happy Coding!