Multi-Module Maven with github pages

Motivation

The issues

• Project pages are not generated correctly
• Module results are not deployed to maven repository

led to the creation of the example project:

• https://github.com/BITPlan/com.bitplan.multimodule which uses
• https://github.com/BITPlan/com.bitplan.pom for the parent pom definition

in which the github maven site plugin is defined with the configuration

<!-- git hub site plugin https://github.com/github/maven-plugins -->
<plugin>
  <groupId>com.github.github</groupId>
  <artifactId>site-maven-plugin</artifactId>
  <version>${site-maven-plugin.version}</version>
  <configuration>
    <message>Creating site for ${github.owner} ${github.project}
      ${project.version}</message>
    <repositoryName>${github.project}</repositoryName>      <!-- github repo name -->
    <repositoryOwner>${github.owner}</repositoryOwner>    <!-- github username -->
  </configuration>
  <executions>
    <execution>
      <goals>
        <goal>site</goal>
      </goals>
      <phase>site</phase>
    </execution>
  </executions>
</plugin>

Following the suggestion of https://stackoverflow.com/a/19336536/1497139 led to adding

  <distributionManagement>
    <site>
      <id>${project.artifactId}-site</id>
      <url>${project.baseUri}</url>
    </site>
  </distributionManagement>

to the parent pom.xml

mvn clean site 
... wait a long while ...

[INFO] Multi-Module ....................................... SUCCESS [04:22 min]
[INFO] Multi-Module 1 ..................................... SUCCESS [04:09 min]
[INFO] Multi-Module 2 ..................................... SUCCESS [04:09 min]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 12:42 min

and you end up with Module 2 overriding the results of the Multi-Module and Module 1 results

Is it a bug or a feature?

• Its a bug!

Whats the work-around?

Do not use the plugin!

mkdir -p /tmp/stage/4site
mvn -U clean install site site:stage -DstagingDirectory=/tmp/stage/4site
[INFO] --- maven-site-plugin:3.7.1:stage (default-cli) @ multimodule2 ---
[INFO] Using this base directory for staging: /tmp/stage/4site
[INFO] Pushing /Users/wf/Documents/workspace/com.bitplan.multimodule/multimodule-module2/target/site
[INFO]    >>> to file:///tmp/stage/4site/../multimodule2/com.bitplan.multimodule/multimodule2
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] Multi-Module ....................................... SUCCESS [  5.423 s]
[INFO] Multi-Module 1 ..................................... SUCCESS [  4.043 s]
[INFO] Multi-Module 2 ..................................... SUCCESS [  3.393 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 13.665 s

Yes - thats right seconds not minutes!

get a local stage of gh-pages yourself

 git clone https://github.com/$owner/$project --branch gh-pages --single-branch

Experimenting with distributionManagement.url settings

For this we wrote a script to log the results of the mvn site command and analyze where the results go

#!/bin/bash
# WF 2018-08-24

# prepare to log the mvn site command
sitelog=/tmp/sitelog$$.txt

# create an empty staging area
stage=/tmp/stage
rm -rf $stage
mkdir -p $stage/4site

# run the staging of the site against this directory and log the results
mvn -U clean install site site:stage -DstagingDirectory=$stage/4site | tee $sitelog

# what url did we set for the site in distributionManagement?
cat ../com.bitplan.pom/pom.xml | xml2 | grep  /project/distributionManagement/site/url 
# and where did the results go?
egrep "(Pushing|to file)"  $sitelog

${project.baseUri}

/project/distributionManagement/site/url=${project.baseUri}
[INFO] Pushing /Users/wf/Documents/workspace/com.bitplan.multimodule/target/site
[INFO]    >>> to file:///tmp/stage/4site/../com.bitplan.multimodule/com.bitplan.multimodule
[INFO] Pushing /Users/wf/Documents/workspace/com.bitplan.multimodule/multimodule-module1/target/site
[INFO]    >>> to file:///tmp/stage/4site/../com.bitplan.multimodule/multimodule-module1/com.bitplan.multimodule/multimodule1
[INFO] Pushing /Users/wf/Documents/workspace/com.bitplan.multimodule/multimodule-module2/target/site
[INFO]    >>> to file:///tmp/stage/4site/../com.bitplan.multimodule/multimodule-module2/com.bitplan.multimodule/multimodule2

• the multimodule index file is at /tmp/stage/com.bitplan.multimodule/com.bitplan.multimodule/index.html ✓
• inter-module links work and the main parent module is at /tmp/stage/com.bitplan.pom/index.html ✓

${project.artifactId}

/project/distributionManagement/site/url=${project.artifactId}

• failed: Base URI is not absolute: com.bitplan.pom -> [Help 1]

https://${github.owner}.github.io/${project.artifactId}

/project/distributionManagement/site/url=https://${github.owner}.github.io/${project.artifactId}
[INFO] Pushing /Users/wf/Documents/workspace/com.bitplan.multimodule/target/site
[INFO]    >>> to file:///tmp/stage/../com.bitplan.multimodule/com.bitplan.multimodule
[INFO] Pushing /Users/wf/Documents/workspace/com.bitplan.multimodule/multimodule-module1/target/site
[INFO]    >>> to file:///tmp/stage/../multimodule1/com.bitplan.multimodule/multimodule1
[INFO] Pushing /Users/wf/Documents/workspace/com.bitplan.multimodule/multimodule-module2/target/site
[INFO]    >>> to file:///tmp/stage/../multimodule2/com.bitplan.multimodule/multimodule2

Example pom.xml files

• https://github.com/kohsuke/pom/blob/master/pom.xml (uses wagon-gitsite ...)
• https://github.com/PathwayCommons/cpath2/blob/master/pom.xml
• https://github.com/CoreMedia/joala/commit/5f12395b8b6d84a39c2c11534ec5a509dace4720

Stackoverflow questions

• https://stackoverflow.com/questions/10848715/multi-module-pom-creating-a-site-that-works
• https://stackoverflow.com/questions/21520904/multi-module-example-of-using-mvn-site-deploy-with-github-pages
  • https://github.com/trajano/app/blob/wagon-git-example/pom.xml
  • https://github.com/khuxtable/wagon-gitsite (2011)
  • https://mvnrepository.com/artifact/com.github.stephenc.wagon/wagon-gitsite (2014-11)

Links

• https://wiki.jenkins.io/display/JENKINS/Site+Creation+and+Deployment

Documentation

• https://maven.apache.org/plugins/maven-site-plugin/
• https://maven.apache.org/plugins/maven-site-plugin/attach-descriptor-mojo.html