lein-exec
Leiningen plugin to execute Clojure scripts
Installation
Lein 2 users
The recommended way is to install as a global plugin in ~/.lein/profiles.clj:
{:user {:plugins [[lein-exec "0.2.1"]]}}
You may also install as a project plugin in project.clj:
:plugins [[lein-exec "0.2.1"]]
Lein 1.x users
Either install as a plugin:
$ lein plugin install lein-exec "0.1"
Or, include as a dev-dependency:
:dev-dependencies [[lein-exec "0.1"]]
Usage
Lein 2 users
This blog post covers lein-exec with examples:
[http://charsequence.blogspot.in/2012/04/scripting-clojure-with-leiningen-2.html] (http://charsequence.blogspot.in/2012/04/scripting-clojure-with-leiningen-2.html)
Synopsis
lein2 exec [-p]
lein2 exec -e[p] <string-s-expr>
lein2 exec [-p] <script-path> [args]
When invoked without args it reads S-expressions from STDIN and evaluates them.
When only option -p is specified, it evaluates STDIN in project context.
-e evaluates the following string as an S-expression
-ep evaluates the following string as an S-expression in project (w/classpath)
-p indicates the script should be evaluated in project (with classpath)
Examples
cat foo.clj | lein2 exec
lein2 exec -e '(println "foo" (+ 20 30))'
lein2 exec -ep "(use 'foo.bar) (pprint (map baz (range 200)))"
lein2 exec -p script/run-server.clj -p 8088
lein2 exec ~/common/delete-logs.clj
Optional args after script-path are bound to clojure.core/*command-line-args*
Getting dependencies from within script
Thanks to the pomegranate library in Leiningen, lein-exec exposes an API to specify dependencies that can be added dynamically to the CLASSPATH:
(use '[leiningen.exec :only (deps)])
(deps '[[ring/ring-core "1.0.0"]
[ring/ring-jetty-adapter "1.0.0"]])
This downloads dependencies from Maven Central and Clojars if required, and uses the local repo on subsequent runs.
Executable scripts
This may be applicable to Unix-like systems only.
To run executable Clojure script files, you need to download the lein-exec and lein-exec-p scripts, make them executable, and put them in PATH. After downloading the scripts, you may also need to edit them in order to specify the correct name for the Leiningen executable.
$ wget https://raw.github.com/kumarshantanu/lein-exec/master/lein-exec
$ wget https://raw.github.com/kumarshantanu/lein-exec/master/lein-exec-p
$ chmod a+x lein-exec lein-exec-p
$ mv lein-exec lein-exec-p ~/bin # assuming ~/bin is in PATH
Executable Clojure script files that need not run only in project-scope should have the following on the first line (shebang):
#!/usr/bin/env lein-exec
or,
#!/bin/bash lein-exec
Executable Clojure script files that are supposed to run only in project-scope should have the following on the first line (shebang):
#!/usr/bin/env lein-exec-p
or,
#!/bin/bash lein-exec-p
Lein 1.x users
You can execute scripts as follows in a project:
$ lein exec scripts/foobar.clj # mention script path
$ lein exec scripts/run-server.clj -p 4000 # with arguments
The script would have project dependencies and source packages on CLASSPATH.
Writing code to eval with lein-exec
It needs to be written as if would be eval'ed (rather than compiled) - example below:
(require '[clojure.string :as str]
'[clojure.pprint :as ppr]
'[com.example.foo :as foo])
(defn baz
[y]
(let [x (str/join y (foo/quux :bla-bla))]
(ppr/pprint [x foo/nemesis])))
(foo/bar :some-stuff)
(do
(println *command-line-args*) ; command-line args as a list
(foo/bar :some-stuff)
(baz ", "))
Getting in touch
On Twitter: @kumarshantanu
On Leiningen mailing list: http://groups.google.com/group/leiningen
Contributors
- https://github.com/jeroenvandijk (Jeroen van Dijk)
- https://github.com/geriatric
License
Copyright (C) 2011-2012 Shantanu Kumar
Distributed under the Eclipse Public License, the same as Clojure.