How to Create a Release of OpenCensus Java (for Maintainers Only)

Build Environments

We deploy OpenCensus Java to Maven Central under the following systems:

  • Ubuntu 14.04

Other systems may also work, but we haven't verified them.


Setup OSSRH and Signing

If you haven't deployed artifacts to Maven Central before, you need to setup your OSSRH (OSS Repository Hosting) account and signing keys.

  • Follow the instructions on this page to set up an account with OSSRH.

    • You only need to create the account, not set up a new project
    • Contact a OpenCensus Java maintainer to add your account after you have created it.
  • (For release deployment only) Install GnuPG and generate your key pair. You'll also need to publish your public key to make it visible to the Sonatype servers.

  • Put your GnuPG key password and OSSRH account information in <your-home-directory>/.gradle/

    # You need the signing properties only if you are making release deployment

Tagging the Release

The first step in the release process is to create a release branch, bump versions, and create a tag for the release. Our release branches follow the naming convention of v<major>.<minor>.x, while the tags include the patch version v<major>.<minor>.<patch>. For example, the same branch v0.4.x would be used to create all v0.4 tags (e.g. v0.4.0, v0.4.1).

In this section upstream repository refers to the main opencensus-java github repository.

Before any push to the upstream repository you need to create a personal access token.

  1. Create the release branch and push it to GitHub:

    $ MAJOR=0 MINOR=4 PATCH=0 # Set appropriately for new release
    $ git checkout -b v$MAJOR.$MINOR.x master
    $ git push upstream v$MAJOR.$MINOR.x

    The branch will be automatically protected by the GitHub branch protection rule for release branches.

  2. For master branch:

    • Change root build files to the next minor snapshot (e.g. 0.5.0-SNAPSHOT).
    $ git checkout -b bump-version master
    # Change version to next minor (and keep -SNAPSHOT)
    $ sed -i 's/[0-9]\+\.[0-9]\+\.[0-9]\+\(.*CURRENT_OPENCENSUS_VERSION\)/'$MAJOR.$((MINOR+1)).0'\1/' \
    $ ./gradlew build
    $ git commit -a -m "Start $MAJOR.$((MINOR+1)).0 development cycle"
    • Go through PR review and push the master branch to GitHub:
    $ git checkout master
    $ git merge --ff-only bump-version
    $ git push upstream master
  3. For vMajor.Minor.x branch:

    • Change root build files to remove “-SNAPSHOT” for the next release version (e.g. 0.4.0). Commit the result and make a tag:
    $ git checkout -b release v$MAJOR.$MINOR.x
    # Change version to remove -SNAPSHOT
    $ ./gradlew build
    $ git commit -a -m "Bump version to $MAJOR.$MINOR.$PATCH"
    $ git tag -a v$MAJOR.$MINOR.$PATCH -m "Version $MAJOR.$MINOR.$PATCH"
    • Change root build files to the next snapshot version (e.g. 0.4.1-SNAPSHOT). Commit the result:
    # Change version to next patch and add -SNAPSHOT
    $ sed -i 's/[0-9]\+\.[0-9]\+\.[0-9]\+\(.*CURRENT_OPENCENSUS_VERSION\)/'$MAJOR.$MINOR.$((PATCH+1))-SNAPSHOT'\1/' \
    $ ./gradlew build
    $ git commit -a -m "Bump version to $MAJOR.$MINOR.$((PATCH+1))-SNAPSHOT"
    • Go through PR review and push the release tag and updated release branch to GitHub:
    $ git checkout v$MAJOR.$MINOR.x
    $ git merge --ff-only release
    $ git push upstream v$MAJOR.$MINOR.$PATCH
    $ git push upstream v$MAJOR.$MINOR.x


Deployment to Maven Central (or the snapshot repo) is for all of the artifacts from the project.


Before building/deploying, be sure to switch to the appropriate tag. The tag must reference a commit that has been pushed to the main repository, i.e., has gone through code review. For the current release use:

$ git checkout -b v$MAJOR.$MINOR.$PATCH tags/v$MAJOR.$MINOR.$PATCH

Initial Deployment

The following command will build the whole project and upload it to Maven Central. Parallel building is not safe during uploadArchives.

$ ./gradlew clean build && ./gradlew -Dorg.gradle.parallel=false uploadArchives

If the version has the -SNAPSHOT suffix, the artifacts will automatically go to the snapshot repository. Otherwise it's a release deployment and the artifacts will go to a staging repository.

When deploying a Release, the deployment will create a new staging repository. You'll need to look up the ID in the OSSRH UI (usually in the form of opencensus-*).

Releasing on Maven Central

Once all of the artifacts have been pushed to the staging repository, the repository must first be closed, which will trigger several sanity checks on the repository. If this completes successfully, the repository can then be released, which will begin the process of pushing the new artifacts to Maven Central (the staging repository will be destroyed in the process). You can see the complete process for releasing to Maven Central on the OSSRH site.


Once deployment is done, go to Github release page, press Draft a new release to write release notes about the new release.

You can use git log upstream/v$MAJOR.$((MINOR-1)).x..upstream/v$MAJOR.$MINOR.x --graph --first-parent or the Github compare tool to view a summary of all commits since last release as a reference. In addition, you can refer to for a list of major changes since last release.

Please pick major or important user-visible changes only.

Update release versions in documentations and build files

After releasing is done, you need to update all readmes and examples to point to the latest version.

  1. Update and gradle/maven build files on master branch:
$ git checkout -b bump-document-version master
# Substitute versions in build files
$ sed -i 's/[0-9]\+\.[0-9]\+\.[0-9]\+\(.*LATEST_OPENCENSUS_RELEASE_VERSION\)/'$MAJOR.$MINOR.$PATCH'\1/' \
# Substitute versions in build.gradle examples in
$ sed -i 's/\(\(compile\|runtime\).\+io\.opencensus:.\+:\)[0-9]\+\.[0-9]\+\.[0-9]\+/\1'$MAJOR.$MINOR.$PATCH'/' \
# Substitute versions in maven pom examples in
$ sed -i 's/\(<version>\)[0-9]\+\.[0-9]\+\.[0-9]\+/\1'$MAJOR.$MINOR.$PATCH'/' \
  1. Update bazel dependencies for subproject examples:

    • Follow the instructions on this page to install bazel migration tool. You may also need to manually apply this patch if you encounter Unable to find a version for ... due to Invalid Range Result error when using it.

    • Use the following command to generate new dependencies file:

    $ bazel run //generate_workspace -- \ \
    --artifact=io.grpc:grpc-all:1.9.0 \
    --artifact=io.opencensus:opencensus-api:$MAJOR.$MINOR.$PATCH \
    --artifact=io.opencensus:opencensus-contrib-grpc-metrics:$MAJOR.$MINOR.$PATCH \
    --artifact=io.opencensus:opencensus-contrib-zpages:$MAJOR.$MINOR.$PATCH \
    --artifact=io.opencensus:opencensus-exporter-stats-prometheus:$MAJOR.$MINOR.$PATCH \
    --artifact=io.opencensus:opencensus-exporter-stats-stackdriver:$MAJOR.$MINOR.$PATCH \
    --artifact=io.opencensus:opencensus-exporter-trace-logging:$MAJOR.$MINOR.$PATCH \
    --artifact=io.opencensus:opencensus-exporter-trace-stackdriver:$MAJOR.$MINOR.$PATCH \
    --artifact=io.opencensus:opencensus-impl:$MAJOR.$MINOR.$PATCH \
    --artifact=io.prometheus:simpleclient_httpserver:0.3.0 \
    • Copy this file to overwrite examples/opencensus_workspace.bzl.

    • Use the following command to rename the generated rules and commit the changes above:

    $ sed -i 's/def generated_/def opencensus_/' examples/opencensus_workspace.bzl
    $ git commit -a -m "Update release versions for all readme and build files."
  2. Go through PR review and merge it to GitHub master branch.

  3. In addition, create a PR to mark the new release in on master branch. Once that PR is merged, cherry-pick the commit and create another PR to the release branch (branch v$MAJOR.$MINOR.x).

Known Issues

Deployment for tag v0.5.0

To rebuild the releases on the tag v0.5.0 use:

$ ./gradlew clean build && ./gradlew uploadArchives

If option -Dorg.gradle.parallel=false is used, you will hit this bug caused by this bug in gradle 3.5.