Maven - Deployment Automation

In project development, normally a deployment process consists of following steps

• Check-in the code from all project in progress into the SVN or source code repository and tag it.
• Download the complete source code from SVN.
  
• Build the application.
• Store the build output either WAR or EAR file to a common network location.
• Get the file from network and deploy the file to the production site.
• Updated the documentation with date and updated version number of the application.

Problem Statement

There are normally multiple people involved in above mentioned deployment process. One team may handles check-in of code, other may handle build and so on. It is very likely that any step may get missed out due to manual efforts involved and owing to multi-team environment. For example, older build may not be replaced on network machine and deployment team deployed the older build again.

Solution

Automate the deployment process by combining

• Maven, to build and release projects,
• SubVersion, source code repository, to manage source code,
• and Remote Repository Manager (Jfrog/Nexus) to manage project binaries.

Update Project POM.xml

We'll be using Maven Release plug-in to create an automated release process.
For Example: bus-core-api project POM.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" 
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
   http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>bus-core-api</groupId>
   <artifactId>bus-core-api</artifactId>
   <version>1.0-SNAPSHOT</version>
   <packaging>jar</packaging> 
   <scm>
      <url>http://www.svn.com</url>
      <connection>scm:svn:http://localhost:8080/svn/jrepo/trunk/
      Framework</connection>
      <developerConnection>scm:svn:${username}/${password}@localhost:8080:
      common_core_api:1101:code</developerConnection>
   </scm>
   <distributionManagement>
      <repository>
         <id>Core-API-Java-Release</id>
         <name>Release repository</name>
         <url>http://localhost:8081/nexus/content/repositories/
         Core-Api-Release</url>
      </repository>
   </distributionManagement>
   <build>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-release-plugin</artifactId>
            <version>2.0-beta-9</version>
            <configuration>
               <useReleaseProfile>false</useReleaseProfile>
               <goals>deploy</goals>
               <scmCommentPrefix>[bus-core-api-release-checkin]-<
               /scmCommentPrefix>
            </configuration>
         </plugin>
      </plugins>
   </build>
</project>

In Pom.xml, following are the important elements we've used

Element	Description
SCM	Configures the SVN location from where Maven will check out the source code.
Repositories	Location where built WAR/EAR/JAR or any other artifact will be stored after code build is successful.
Plugin	maven-release-plugin is configured to automate the deployment process.

Maven Release Plug-in

The Maven does following useful tasks using maven-release-plugin.

mvn release:clean

It cleans the workspace in case the last release process was not successful.

mvn release:rollback

Rollback the changes done to workspace code and configuration in case the last release process was not successful.

mvn release:prepare

Performs multiple number of operations

• Checks whether there are any uncommitted local changes or not
• Ensures that there are no SNAPSHOT dependencies
• Changes the version of the application and removes SNAPSHOT from the version to make release
• Update pom files to SVN.
• Run test cases
• Commit the modified POM files
• Tag the code in subversion
• Increment the version number and append SNAPSHOT for future release
• Commit the modified POM files to SVN.

mvn release:perform

Checks out the code using the previously defined tag and run the Maven deploy goal to deploy the war or built artifact to repository.
Let's open command console, go the C:\ > MVN >bus-core-api directory and execute the following mvn command.

C:\MVN\bus-core-api>mvn release:prepare

Maven will start building the project. Once build is successful run the following mvn command.

C:\MVN\bus-core-api>mvn release:perform

Once build is successful you can verify the uploaded JAR file in your repository.