Clojure#

Supported Clojure versions#

Semaphore 2.0 Virtual Machine (VM) comes with the Leiningen tool preinstalled. The name of the binary executable is lein which is what will be used in the Semaphore 2.0 project presented in this page.

Changing Clojure version#

The version of Clojure that is going to be used on a project generated by Leiningen depends on the contents of the project.clj file. It can be found in the root directory of each Leiningen project. Therefore, there is no need to execute a specific command in order to change the current Clojure version.

Dependency management#

You can use Semaphore's cache tool to store and load any files or Clojure libraries that you want to reuse between jobs.

System dependencies#

Clojure projects might need packages like database drivers. As you have full sudo access on each Semaphore 2.0 VM, you are free to install all required packages.

A sample Clojure project#

The following .semaphore/semaphore.yml file illustrates how to execute two Clojure projects created using the Leiningen tool:

version: v1.0
name: Clojure Language Guide
agent:
  machine:
    type: e1-standard-2
    os_image: ubuntu2004

blocks:
  - name: Lein version
    task:
      jobs:
      - name: Print lein version
        commands:
          - lein version

  - name: Compile with Clojure 1.9.0
    task:
      jobs:
      - name: Hello World 1.9.0
        commands:
          - checkout
          - cd one
          - lein run

  - name: Compile with Clojure 1.10.0
    task:
      jobs:
      - name: Hello World 1.10.0
        commands:
          - checkout
          - cd two
          - lein run

For the one project, the contents of project.clj are as follows:

(defproject hw "0.1.0-SNAPSHOT"
  :main one.core
  :dependencies [[org.clojure/clojure "1.9.0"]])

This is where you specify the Clojure version you want to use for your project which, in this case, is 1.9.0.

For the two project, the contents of project.clj are as follows:

(defproject hw "0.1.0-SNAPSHOT"
  :main two.core
  :dependencies [[org.clojure/clojure "1.10.0"]])

Again, this is where you specify the Clojure version you want to use for your project which, in this case, is 1.10.0.

To sum up, project one uses Clojure version 1.9.0 whereas project two uses Clojure version 1.10.0.

The contents of the ./src/one/core.clj file from the one project are as follows:

(ns one.core)

(defn -main [& args]
  (println "Hello World!")
  (println "Clojure 1.9.0"))

The contents of the ./src/two/core.clj file from the two project are as follows:

(ns two.core)

(defn -main [& args]
  (println "Hello World!")
  (println "Clojure 1.10.0!"))

See Also#