Hi Austin, I think those Takari projects aren't maintained anymore. The issue was recently fixed in Maven 3.8.2 with https://issues.apache.org/jira/browse/MNG-4706
You can use the command line -Dmaven.ext.class.path to include the extension. The strange wording is perhaps because there is an idea in the Maven community that command line arguments are second-class citizens to configuration written into the pom files, and conversely that you can throw whatever arguments in and it will not interfere with existing configuration. There is some truth to this, as arguments to config a plugin are honoured, but not if the same config has been configured in a pom. You can also add the extensions for the system to /usr/share/maven/lib/ext Thanks, Delany On Thu, 30 Sept 2021 at 07:45, Austin Witt <[email protected]> wrote: > I wish to install a Maven extension - Takari's Concurrent Safe Local > Repository extension ( > http://takari.io/book/30-team-maven.html#concurrent-safe-local-repository > ) > - on a system such that it's picked up by all Maven runs. > > Individual projects should not have to put it in their pom.xml; I do not > want projects to be able to opt-out of this extension, and I do not want > them to have to opt-in. > Individual projects should not have to put it in their > basedir/.mvn/extensions.xml; I do not want projects to be able to opt-out > of this extension, and I do not want them to have to opt-in. > > However... > > This is a CICD system where builds run in Docker containers, and each get > their *own* ~/.m2 directory (complete with their own self-specified > settings.xml), which the builds themselves set up *if they need it* at > build-time. So, there isn't a ~/.m2/lib/ext that I can drop the extension > JAR into "ahead-of-time" before Maven runs - to put it there, I'd have to > modify each project's pipeline to drop the JAR in before kicking off any > Maven processes. > > I am looking for a way to provide the extension as default functionality > for *all* Maven processes on a system, without requiring an individual > "maven project in a git repo" to be aware of it. > > I am not entirely sure I understand how the final Extension > mechanism, -Dmaven.ext.class.path, works. It *seems like* I could add that > via environment variables as a global maven option, and point at a JAR > somewhere *else *on the system. However, the documentation I could find on > it cautions: > > -Dmaven.ext.class.path=[path to files] is a little bit more flexible, but > remains not configured into the build, which is not suitable to ensure an > extension is available at build time. > -- https://maven.apache.org/studies/extension-demo/ > > > What does "not configured into the build, which is not suitable to ensure > an extension is available at build time" *mean* ? Is it just saying that > it's not loaded before the project is parsed and so is unsuitable for > extensions that require that, as identified in the line about pom.xml > extension configuration? All documentation I can find about > -Dmaven.ext.class.path talks about EventSpy implementations - does it > *only* work > for those? Or can I load other extensions via that mechanism? > > If -Dmaven.ext.class.path works with all extension types *and* loads > in-time for Takari's extension, I can probably use that. > > If not, is there a way to change the Maven extension directory with a > property? E.g. mvn -Dext.dir=/opt/some/dir and have that used, instead of > the user-local ~/.m2/lib/ext? > > Thank you for your time, > Austin >
