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Maven Central

Channels can publish to Maven Central through gradle-maven-publish-plugin 0.34.0 or newer. Apply and configure that plugin as usual. PublishData sets the version and routes each build:

plugins {
    `java-library`
    id("com.vanniktech.maven.publish") version "0.37.0"
    id("de.chojo.publishdata") version "2.1.0"
}

mavenPublishing {
    publishToMavenCentral()
    signAllPublications()
    pom { … }
}

publishData {
    channels {
        release { publishToMavenCentral() }                  // tags to Maven Central
        snapshot("https://repo.example.com/snapshots")       // branches to your snapshot repository
    }
}
./gradlew publishChannel

runs publishToMavenCentral on a tag and publishes to the snapshot repository otherwise. A channel can have a repository and publishToMavenCentral() at once. It then publishes to both.

Things to know​

  • Use publishChannel, not publish. The vanniktech plugin registers its own Central repository, and publish would upload branch builds there as well.
  • The publication and its coordinates come from the vanniktech plugin. Set them with its coordinates(…). publishData.groupId and artifactId only apply to the publication PublishData creates itself.
  • Credentials and signing are configured as the vanniktech plugin documents them (mavenCentralUsername, signingInMemoryKey, …). The snapshot repository takes its credentials through repository { }.
  • With signAllPublications(), versions ending in -SNAPSHOT are published unsigned when no key is configured. Every other version needs the signing key, also outside Maven Central. A dev channel (1.5.0-DEV) therefore needs the key on dev branches. branchSuffix() does not.
  • Release uploads to Maven Central do not support the configuration cache yet, a limit of the vanniktech plugin. Run them with --no-configuration-cache. Snapshots work with it.
  • publishToMavenCentral() without the vanniktech plugin is reported as a warning, and publishChannel fails on the builds that would go to Maven Central.