Suppress Maven repository output

[jglick]

In the maven build pack, you should arrange for the generated Jenkinsfile to say

  environment {
    // …as before, then:
    MAVEN_OPTS = '-Dorg.slf4j.simpleLogger.log.org.apache.maven.cli.transfer.Slf4jMavenTransferListener=warn'
  }

I am not sure exactly how to do this; this line implies that it can be plugged in somewhere, but I can find nothing in this repository nor in jenkins-x-kubernetes that seems to set an Environment block, and the struct field PipelineConfig.Environment is apparently unused.

At any rate, if you make that change, the dozens of lines cluttering a typical serverless build such as

[INFO] Downloading from nexus: http://nexus/repository/maven-group/org/codehaus/plexus/plexus-compiler-javac/2.2/plexus-compiler-javac-2.2.pom
[INFO] Downloaded from nexus: http://nexus/repository/maven-group/org/codehaus/plexus/plexus-compiler-javac/2.2/plexus-compiler-javac-2.2.pom (769 B at 154 kB/s)
[INFO] Downloading from nexus: http://nexus/repository/maven-group/org/codehaus/plexus/plexus-compilers/2.2/plexus-compilers-2.2.pom
[INFO] Downloaded from nexus: http://nexus/repository/maven-group/org/codehaus/plexus/plexus-compilers/2.2/plexus-compilers-2.2.pom (1.2 kB at 207 kB/s)

are suppressed, so you can see the interesting build output. Potential downsides:

• If the build hangs trying to access Nexus, it will not be obvious why.
• The deploy goal shows only

  [INFO] Using alternate deployment repository local-nexus::default::http://nexus/repository/maven-releases/

  and does not display that it has actually uploaded something.

[jglick]

Note that batch mode is implicit.