clojure-maven-plugin conveniently integrates Clojure tooling and processing steps into your Maven builds. Intentionally Spartan, it is specifically designed to wrangle those critters commonly found in Clojure- and Java-slinging development shops, likely the ones you are using now:

• Apache Maven, the primary driver of your build.
• clojure CLI tooling and its deps.edn ecosystem.
• Leiningen project.clj workflows.

This plugin doesn't offer any new packaging type such as clojure.

Usage

First, ensure your Maven build uses the Clojars repository for dependency and plugin resolution with this snippet:

<repository>
    <id>clojars.org</id>
    <url>https://repo.clojars.org/</url>
</repository>

in each of the <repositories> and <pluginRepositories> sections in the appropriate Maven configuration, such as your pom.xml.

clojure goal

Execute the CLI clojure command in a sub-process using the Maven project classpath.

<plugin>
    <groupId>vivid</groupId>
    <artifactId>clojure-maven-plugin</artifactId>
    <version>0.3.0</version>
    <executions>
        <execution>
            <id>leiningen-release-build</id>         <!-- Each execution requires a unique ID -->
            <phase>compile</phase>                   <!-- Tie goal execution to the desired Maven phase -->
            <goals>
                <goal>clojure</goal>                 <!-- The vivid:clojure-maven-plugin Clojure goal -->
            </goals>
            <configuration>

                <!-- Optional path to the clojure executable -->
                <executable>clojure</executable>

                <!-- Optional arguments to Clojure. CDATA might be necessary to handle dashes. -->
                <args>release</args>

                <!-- Maven classpath scope provided to `clojure`.
                     Defaults to COMPILE. Other values are TEST and NONE. -->
                <classpathScope>TEST</classpathScope>

                <!-- Defaults to Maven's default of just src/main/clojure -->
                <sourcePaths>
                    <sourcePath>src/main/clojure</sourcePath>
                </sourcePaths>

                <!-- Defaults to Maven's default of just src/test/clojure -->
                <testPaths>
                    <testPath>src/test/clojure</testPath>
                </testPaths>

            </configuration>
        </execution>
    </executions>
</plugin>

clojure.test goal

Skip tests by setting the skip parameter to true. Also honors the maven.test.skip parameter and -Dclojure-maven-plugin.clojure.test.skip=true.

deps.edn goal

Writes a deps.edn file that replicates each of the clojure goal execution configurations in the POM. They can then be directly run by the clojure CLI tools. The Maven goal runs during the generate-resources phase by default.

<plugin>
    <groupId>vivid</groupId>
    <artifactId>clojure-maven-plugin</artifactId>
    <version>0.3.0</version>
    <executions>
        <execution>
            <id>hello-wumpus</id>                     <!-- Each 'clojure' goal execution ID servers as the deps.edn alias -->
            <goals><goal>clojure</goal></goals>
            ...
        </execution>
        ...
        <execution>
            <goals>
                <goal>deps.edn</goal>                 <!-- The vivid:clojure-maven-plugin deps.edn goal -->
            </goals>
            <configuration>

                <!-- Optional. Specify where to write the file. If a directory, deps.edn will
                     be written to that directory. Paths in deps.edn are written relative to
                     Maven's $project.basedir -->
                <pathname>../projects/deps.edn</pathname>

            </configuration>
        </execution>
    </executions>
</plugin>

To run the deps.edn goal from the CLI:

$ mvn vivid:clojure-maven-plugin:deps.edn
...
[INFO] --- clojure-maven-plugin:0.3.0:deps.edn (default-cli) @ multiple-use-project ---
[INFO] Wrote deps.edn

Continuing with the running example, the deps.edn file now has an :alias for :hello-wumpus that replicates the same classpath and options as its originating clojure Maven goal:

{:aliases {:hello-wumpus {:extra-paths ["src/main/clojure"
                                        "target/classes"]
                          :main-opts ["-m hello-wumpus.core"]
                          :extra-deps {org.clojure/clojure {:mvn/version "1.10.1"}}}
           ... }}

and can be run with:

$ clojure -A:hello-wumpus
Hello from planet Irata!

Useful for bringing a build into other tooling for further work or experimentation. Now, wasn't that .. anticlimactic? And, boring? And time-saving? And effective? And reliable? Just like Maven..

leiningen goal

Execute Leiningen directly within Maven's running process. Faster and less resource-intensive than running lein in a sub-process.

<plugin>
    <groupId>vivid</groupId>
    <artifactId>clojure-maven-plugin</artifactId>
    <version>0.3.0</version>
    <executions>
        <execution>
            <id>leiningen-release-build</id>         <!-- Each execution requires a unique ID -->
            <phase>compile</phase>                   <!-- Bind goal execution to the desired Maven phase -->
            <goals>
                <goal>leiningen</goal>               <!-- The vivid:clojure-maven-plugin Leiningen goal -->
            </goals>
            <configuration>

                <!-- Immediately prior to running Leiningen, vivid:clojure-maven-plugin will
                     automatically download the specified version of Leiningen and its
                     dependencies as necessary using Maven's dependency resolution system. -->
                <version>2.9.3</version>

                <!-- Leiningen tasks, aliases. Any valid 'lein' CLI arguments can be used here. -->
                <args>release</args>

            </configuration>
        </execution>
    </executions>
</plugin>

Current working directory: For the duration of an invocation of Leiningen, both user.dir and Leiningen's own leiningen.core.main/*cwd* var are set to the Maven module's basedir, giving Leiningen and its various tasks the information they need to correctly determine the current working directory. Afterwards user.dir is restored to its prior value. Portions of a Leiningen run might express ill behavior with file paths in the context of a Maven multi-module build; tasks must account for user.dir.

Development

Run the tests and build the deliverables:

bin/test.sh

Motivation: Among the methods of integration Clojure tooling into Maven, none provided the integrative experience of IntelliJ (Maven classpath) and CI (JUnit reporting).

License and Attributions

This project is licensed under the Apache License Version 2.0, modulo portions derived from these donors:

• Inge Solvoll lein-maven-plugin. MIT License.

• James Reeves eftest. Eclipse Public License 1.0.

• Talios clojure-maven-plugin. Eclipse Public License 1.0.

• CMP logo illustration by ei8htz.

© Copyright Vivid Inc.