how do I get sbt to use a local maven proxy repository (Nexus)?

Step 1: Follow the instructions at Detailed Topics: Proxy Repositories, which I have summarised and added to below:

1. (If you are using Artifactory, you can skip this step.) Create an entirely separate Maven proxy repository (or group) on your corporate Maven repository, to proxy ivy-style repositories such as these two important ones:

   • http://repo.typesafe.com/typesafe/ivy-releases/
   • http://repo.scala-sbt.org/scalasbt/sbt-plugin-releases/

   This is needed because some repository managers cannot handle Ivy-style and Maven-style repositories being mixed together.

2. Create a file repositories, listing both your main corporate repository and any extra one that you created in step 1, in the format shown below:

   [repositories]
     my-maven-proxy-releases: http://repo.example.com/maven-releases/
     my-ivy-proxy-releases: http://repo.example.com/ivy-releases/, [organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]
   

3. Either save that file in the .sbt directory inside your home directory, or specify it on the sbt command line:

   sbt -Dsbt.repository.config=<path-to-your-repo-file>
   

Good news for those using older versions of sbt: Even though, in the sbt 0.12.0 launcher jar at least, the boot properties files for older sbt versions don’t contain the required line (the one that mentions repository.config), it will still work for those versions of sbt if you edit those files to add the required line, and repackage them into the sbt 0.12.0 launcher jar! This is because the feature is implemented in the launcher, not in sbt itself. And the sbt 0.12.0 launcher is claimed to be able to launch all versions of sbt, right back to 0.7!

Step 2: To make sure external repositories are not being used, remove the default repositories from your resolvers. This can be done in one of two ways:

1. Add the command line option -Dsbt.override.build.repos=true mentioned on the Detailed Topics page above. This will cause the repositories you specified in the file to override any repositories specified in any of your sbt files. This might only work in sbt 0.12 and above, though – I haven’t tried it yet.
2. Use fullResolvers := Seq( resolver(s) for your corporate maven repositories ) in your build files, instead of resolvers ++= or resolvers := or whatever you used to use.