How to publish Scala library to Central Repository?

What is Central Repository?

The Central Repository is the largest collection of Java and other open-source components. It provides the easiest way to access and distribute your software components to millions of developers. It is the default repository for Apache Maven, SBT, and other build systems and can be easily used from Apache Ant/Ivy, Gradle, and many other tools.

What is Sonatype?

Sonatype is a Fulton, Maryland-based cybersecurity company helping enterprises get precise intelligence about open source components and software security

What is the relationship between Sonatype and Central Repository?

Sonatype is the steward, maintainer, and financial sponsor of the Central Repository and is determined to continue to provide it to the community of consumers and providers of components.

How to prepare the publishing?

1. Sign up Sonatype JIRA account

2. Create a New project ticket

   

   The most important field is Group Id, you need to own the corresponding domain, if you don’t own a domain, you can also use the GitHub account io.github.(account), here is the feedback I got from Sonatype

   

How to publish Scala artifact?

Add plugins

Add the following line in project/plugins.sbt

addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.9.9") // manage sonatype related stuff
addSbtPlugin("com.jsuereth" % "sbt-pgp" % "2.0.1") // manage gpg related stuff
addSbtPlugin("com.github.sbt" % "sbt-release" % "1.1.0") // manage the release process

Rewrite release task

Add the following line in build.sbt

    releaseProcess := Seq[ReleaseStep](
      checkSnapshotDependencies,
      inquireVersions,
      runClean,
      runTest,
      setReleaseVersion,
      commitReleaseVersion,
      tagRelease,
      releaseStepCommandAndRemaining("+publishSigned"),
      releaseStepCommand("sonatypeBundleRelease"),
      setNextVersion,
      commitNextVersion,
      pushChanges
    )

Generate GPG key

1. Run the following command to generate key

   gpg --gen-key
   

   

2. Send the key to the server supported by Sonatype

     gpg --keyserver keyserver.ubuntu.com --send-keys <gpg key>
   

Add required credentials

1. Create a sonatype.sbt in ~/.sbt/<version>/sonatype.sbt
2. Add the following line in sonatype.sbt

   credentials += Credentials("Sonatype Nexus Repository Manager",
         "s01.oss.sonatype.org",
         "<Sonatype JIRA Account Name>",
         "<Sonatype JIRA Account Password>")
   credentials += Credentials(
     "<gpg key uid>",
     "gpg",
     "<gpg key>", // key identifier
     "ignored" // this field is ignored; passwords are supplied by pinentry
   )
   

Run release command

Run release in sbt

sbt> release

Then you can view the library in Central Repository