Releasing Micrometer
This page documents the release process for Micrometer and is intended as a reference for Micrometer maintainers.
Git tags in a specific format are how we mark and start the release process. Once tagged, our CI workflow will run for the new tag and perform the release process.
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See the deploy script used to publish artifacts
Once all changes for a release have been made and CI builds are passing, start the release process by following the steps below.
A git tag and GitHub release can be made together at https://github.com/micrometer-metrics/micrometer/releases/new. Make maintenance release tags from the corresponding maintenance branch. For example, a release version 1.1.2 would be tagged as v1.1.2 from the 1.1.x branch.
The CI workflow will go through the steps of building, testing, and publishing the artifacts for the version.
After the workflow publishes the artifacts to jcenter, it will pause for approval to proceed. Any checks/tests of the release artifacts can be done using the release version and the jcenter repository.
If everything is satisfactory in the previous step, approve the waiting approval job on CircleCI. Then the last job will sync the release artifacts from jcenter to Maven Central.
Syncing artifacts to Maven Central can take a long time and there are a variety of timeouts we need to worry about. The HTTP client used to make the call for syncing has timeouts (see spring-gradle-plugins/spring-bintray-plugin#3). Until these timeouts are increased or made configurable, we can restart the sync job (NOT the whole workflow; see next paragraph) and hope the timeouts are not reached on another attempt. CircleCI also has a timeout for no output (see Build has hit timeout limit). For this, we can increase the no_output_timeout for the maven sync command (see a73f7d0).
To restart a failed job without running the whole workflow again, select the arrow to the right of "Rerun" on the failed workflow from the workflows view, and choose "Rerun from failed".
To make a release, you need to have privileges to push tags to this repository. Secrets are encrypted and the key to decrypt them needs to be configured in the CI. You need privileges on the Micrometer CircleCI to approve the job that blocks the Maven Central sync. That’s it. The rest is handled by plugins, scripts, and workflows.
Knowing these details shouldn’t be necessary for successfully making releases, but if interested you can check them.
The project version is determined at build time by the spring-release-plugin which extends the nebula-release-plugin.
The publishing of artifacts and versions to Bintray is handled by the spring-bintray-plugin which extends the gradle-bintray-plugin.