Leiningen 2

Humane build management for

ClojureMadeSimple.co.uk

This slide deck is available to follow along with on slideshare.net

slideshare.net/jr0cket

of Java build management

...there was Ant,Ant begat Ivy,

Ant begat Maven

… and there was much XML all around

build management

Human verses Computer readable build jobs

Leiningen… more fun than Maven

… easy way to kick-start your Clojure addiction

Leiningen: Manual install

Download the Leiningen 2 install script from

leiningen.org

Move the lein file to an executable location, eg.

~/bin

Make the install script executable and run the install

chmod u+x ~/bin/lein

lein

Leiningen: package managers

● Ubuntu● Debian● Fedora● CentOS

Leiningen also staring in

Eclipse plugin Counter Clockwise

All the usual tasks...

lein new

lein deps

lein run

lein jar

● Create a new clojure project

● Download all dependencies

● Run your application

● Deploy your app as a jar

...and then some

lein uberjar

lein repl

jack-in

- Include Clojure & all your dependencies in one jar

- Fire up the dynamic coding environment (REPL)

- Hook to start a REPL from within Emacs

lein replFire up the REPL

REPL: read, evaluate, print loop – dynamic environment for Clojure and other lisps

Typing code into the REPL

Develop functions and data structures on the fly

REPL: read, evaluate, print loop – dynamic environment for Clojure and other lisps

lein new my-projectcd my-projectlein deps

Create a new project

Lein deps will check your project.clj configuration file and download any libraries (jar files) that are required by the project

Anatomy of a new project

Note: dashes in project names are converted to underscores to make Java happy!

Over-riding defaults

lein new template-name my-project

Create project with a different template

Example: WebNoir template

lein new noir fpdays2012-web

cd my-project

git init

Create a repo on github & add it to your project

git remote add origin git@github.com/account/project.git

git push -u origin master

Version your project with Git

You may want to edit your .git-ignore file also

cd my-projectemacs project.clj

Open project in emacs

project.clj - project definition

Lein deps will check this project.clj configuration file and download any libraries (jar files) that are required by the project

Group Dependencies

Usually a reversed domain name

Dev Dependencies

Dev-dependencies: Add libraries only needed for development, not packaged when code deployed

https://clojars.org/

http://search.maven.com

Add a REPL session

REPL: read, evaluate, print, loop – dynamic environment for Clojure and other lisps

Add REPL session to all projects

~/.lein/profiles.clj

M – x clojure-jack-in

Fire up the REPL in Emacs

M – x represents the keyboard combination of the meta key followed by x. Then the command clojure-jack-in is entered.

REPL in Emacs

Add web based REPL

REPL: read, evaluate, print, loop – dynamic environment for Clojure and other lisps

~/.lein/profiles.clj

Leiningen WebRepl plugin

Local Repositories

(just like Maven)

Libraries kept in local .m2 folder

Repositories

https://github.com/technomancy/leiningen/blob/preview/sample.project.clj

Running your project

lein runRuns the main function, or specify main with -m option

Create a new project

lein trampoline run

-m my-app.server 5000

Long running processes

Web applications - noir - enclojure - ring

lein tests

lein tests my.proj.code

lein help tests

Running Tests

Automating test runs ?

Deployment

Jars & Uber Jarslein jar- package up your project,

requires Clojure on the server

lein uberjar- package up everything, even Clojure

project.clj for jar / uberjar

Clojure code for jar / uberjar

Deploy to Clojars

Create a maven pom

lein pom

Create a maven pom

scp pom.xml myproject-0.1.0.jar clojars@clojars.org:

Deploy to Clojars

Or just use lein-clojars

https://github.com/ato/lein-clojars

Deploying to the Cloud

Uses your Leiningen project.clj

- Create your account & install the toolbelt

- Create your instance

- Push your git repo

- Fire up your browser

blog.raynes.me/blog/2011/11/03/moving-try-clojure-to-heroku/

devcenter.heroku.com/articles/clojure-web-application

Leiningen Plug-ins

Running scriptsCopying files

DVCS (git)Continuous

Integration server (Jenkins)

Leiningen.org- Tutorials

- Github Repository- News

- Bug reporting

Choose Life...Choose Life...

… … choose Clojurechoose Clojure

Thank you

@jr0cket

ClojureMadeSimple.co.uk

slideshare.net/jr0cket