Accessing local repository in offline mode

Question

I need to make Maven access local repository (file://) when it is ran in offline mode (basically, I am trying to setup repository hierarchy so it does not put artifacts where I don't need them).

This does not work out-of-the-box, though I always assumed this scenario is supported. Is there some flag to enable particular repository in offline mode?

Answer 1

For the dev environment only, if you use IntelliJ IDEA, you can configure Maven to work offline as follow:

Preferences... > Search for Maven > Work offline (checked)

Answer 2

It is possible to set up profiles for repositories utilizing the local file system rather than a network address.

<repository>
   <id>mymaven</id>
   <url>file://D:\mylocalrepo</url>
</repository>

According to documentation, it is also possible to reference offline mode in a property value.

${settings.offline}

You would then leverage these together to activate a given settings profile according to the examples here. (If Maven doesn't detect the property, try evaluating it directly using the above syntax.)

  <profiles>
    <profile>
      <id>myNeededProfile</id>
      <activation>
        <activeByDefault>false</activeByDefault>
        ...
        <property>
          <name>offline</name>
          <value>true</value>
        </property>
        ...
      </activation>
      ...
    </profile>
  </profiles>

I believe that the Maven Help Plugin can guide this development by computing which profile will be active under certain conditions.

I also think that this could be accomplished more simply by explicitly invoking a profile from the command line each time offline mode is requested.

mvn groupId:artifactId:goal -o -P profile-1,profile-2

Or, even more straightforwardly, by having two separate settings files and subbing them out specifically for the offline/online operations. You could write a command-line wrapper in whatever OS environment you're using to detect the offline request, then move and rename the files before executing the Maven commands, then move them back upon completion.