Retrieve svn last changed revision number with the buildnumber-maven-plugin

Question

I'm currently developing a microservice based architecture for my application. I've got a maven multi-module project which has many services, so I can easily deploy them to the docker hub using the maven deploy command and also a maven docker plugin.

Still, the docker image tags are based in the project version number, while I would like to have them tagged with each repository's last changed revision number. From the time being, I'm trying just to add this field as a manifest entry using the buildnumber-maven-plugin:

Let's say that's my multi-module project:

<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>
...

    <modules>
        <module>module-a</module>
        <module>module-b</module>
    </modules>

...

</project>

And the model for module-a would be:

<?xml version="1.0" encoding="UTF-8"?>
<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">
    ...


    <scm>
        <connection>scm:svn:http://myrepo.com/svn/application/module-a</connection>
    </scm>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>buildnumber-maven-plugin</artifactId>
                <version>1.4</version>
                <executions>
                    <execution>
                        <phase>validate</phase>
                        <goals>
                            <goal>create</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <doCheck>false</doCheck>
                    <doUpdate>true</doUpdate>
                    <useLastCommittedRevision>true</useLastCommittedRevision>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifestEntries>
                            <SCM-Revision>${buildNumber}</SCM-Revision>
                        </manifestEntries>
                    </archive>
                </configuration>
            </plugin>
            ....
        </plugins>
    </build>

    <dependencies>
        ...
    </dependencies>

</project>

The issue is that {buildNumber} evaluates to my working copy number, which is the one referring to the last commit made to the repository and not to the scm:svn:http://myrepo.com/svn/application/module-a location. To explain it better, when I display the properties of module-a from tortoise I've got this:

What I want is to retrieve 3248 which refers to the last real change made to module-a, instead of 3257 (working copy), which is what I'm getting from the plugin. That way the docker plugin would know if it's a different image tag and push it only if changes were made to the module in the repo.

Answer 1

I couldn't get buildnumber-maven-plugin to work for this same scenario either. <useLastCommittedRevision> does not work in v1.4 and in v1.3 it does not return the last changed revision but the penultimate one in some situations.

There is a crafty workaround you can do to get the last changed revision number from svn info command output. Two options depending on your SVN version:

1. For SVN v1.9 or newer versions, use maven-antrun-plugin to run svn info --show-item=last-changed-revision and save the output into a property.

   <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-antrun-plugin</artifactId>
       <version>1.8</version>
       <executions>
           <execution>
               <phase>validate</phase>
               <goals>
                   <goal>run</goal>
               </goals>
               <configuration>
                   <exportAntProperties>true</exportAntProperties>
                   <target>
                       <exec executable="svn" outputProperty="svn.info">
                           <arg value="info"/>
                           <arg value="--show-item=last-changed-revision"/>
                       </exec>
                   </target>
               </configuration>
           </execution>
       </executions>
   </plugin>
   <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-jar-plugin</artifactId>
       <configuration>
           <archive>
               <manifestEntries>
                   <SCM-Revision>${svn.info}</SCM-Revision>
               </manifestEntries>
           </archive>
       </configuration>
   </plugin>
   

2. For SVN versions older than v1.9 (v1.8.13 in my case) you can use maven-antrun-plugin to run svn info --xml and save the output into a property, and build-helper-maven-plugin to parse the contents of that property with a regular expression, matching the last changed revision number and saving it into a second property.

   I chose to add the --xml parameter because basic svn info output is translated depending on the language of the installation, but the xml output format is always the same.

   <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-antrun-plugin</artifactId>
       <version>1.8</version>
       <executions>
           <execution>
               <phase>validate</phase>
               <goals>
                   <goal>run</goal>
               </goals>
               <configuration>
                   <exportAntProperties>true</exportAntProperties>
                   <target>
                       <exec executable="svn" outputProperty="svn.info">
                           <arg value="info"/>
                           <arg value="--xml"/>
                       </exec>
                   </target>
               </configuration>
           </execution>
       </executions>
   </plugin>
   <plugin>
       <groupId>org.codehaus.mojo</groupId>
       <artifactId>build-helper-maven-plugin</artifactId>
       <version>3.0.0</version>
       <executions>
           <execution>
               <id>regex-svn-last-rev</id>
               <goals>
                   <goal>regex-property</goal>
               </goals>
               <configuration>
                   <!-- Output property -->
                   <name>svn.last.rev</name>
                   <value>${svn.info}</value>
                   <regex>^[\s\S]*?commit[\s\S]*?revision=\"(\d+?)\"[\s\S]*?$</regex>
                   <replacement>$1</replacement>
                   <failIfNoMatch>false</failIfNoMatch>
               </configuration>
           </execution>
       </executions>
   </plugin>       
   <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-jar-plugin</artifactId>
       <configuration>
           <archive>
               <manifestEntries>
                   <SCM-Revision>${svn.last.rev}</SCM-Revision>
               </manifestEntries>
           </archive>
       </configuration>
   </plugin>
   

Answer 2

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>buildnumber-maven-plugin</artifactId>
    <version>1.3</version>
    <executions>
        <execution>
            <phase>validate</phase>
            <goals>
                <goal>create</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <doCheck>false</doCheck>
        <doUpdate>true</doUpdate>
        <useLastCommittedRevision>true</useLastCommittedRevision>
    </configuration>
</plugin>

This worked for me.