# Release Process

## Semantic Convention Generation

If a new version of the OpenTelemetry Specification has been released it will be necessary to generate a new
semantic convention package from the YAML definitions in the specification repository. There is a `semconvgen` utility
installed by `make tools` that can be used to generate the a package with the name matching the specification
version number under the `semconv` package. This will ideally be done soon after the specification release is
tagged. Make sure that the specification repo contains a checkout of the the latest tagged release so that the
generated files match the released semantic conventions.

There are currently two categories of semantic conventions that must be generated, `resource` and `trace`.

```
.tools/semconvgen -i /path/to/specification/repo/semantic_conventions/resource -t semconv/template.j2
.tools/semconvgen -i /path/to/specification/repo/semantic_conventions/trace -t semconv/template.j2
```

Using default values for all options other than `input` will result in using the `template.j2` template to
generate `resource.go` and `trace.go` in `/path/to/otelgo/repo/semconv/<version>`.

There are several ancillary files that are not generated and should be copied into the new package from the
prior package, with updates made as appropriate to canonical import path statements and constant values.
These files include:

* doc.go
* exception.go
* http(_test)?.go
* schema.go

Uses of the previous schema version in this repository should be updated to use the newly generated version.
No tooling for this exists at present, so use find/replace in your editor of choice or craft a `grep | sed`
pipeline if you like living on the edge.

## Pre-Release

First, decide which module sets will be released and update their versions
in `versions.yaml`.  Commit this change to a new branch.

Update go.mod for submodules to depend on the new release which will happen in the next step.

1. Run the `prerelease` make target. It creates a branch
    `prerelease_<module set>_<new tag>` that will contain all release changes.

    ```
    make prerelease MODSET=<module set>
    ```

2. Verify the changes.

    ```
    git diff ...prerelease_<module set>_<new tag>
    ```

    This should have changed the version for all modules to be `<new tag>`.
    If these changes look correct, merge them into your pre-release branch:

    ```go
    git merge prerelease_<module set>_<new tag>
    ```

3. Update the [Changelog](./CHANGELOG.md).
   - Make sure all relevant changes for this release are included and are in language that non-contributors to the project can understand.
       To verify this, you can look directly at the commits since the `<last tag>`.

       ```
       git --no-pager log --pretty=oneline "<last tag>..HEAD"
       ```

   - Move all the `Unreleased` changes into a new section following the title scheme (`[<new tag>] - <date of release>`).
   - Update all the appropriate links at the bottom.

4. Push the changes to upstream and create a Pull Request on GitHub.
    Be sure to include the curated changes from the [Changelog](./CHANGELOG.md) in the description.

## Tag

Once the Pull Request with all the version changes has been approved and merged it is time to tag the merged commit.

***IMPORTANT***: It is critical you use the same tag that you used in the Pre-Release step!
Failure to do so will leave things in a broken state. As long as you do not
change `versions.yaml` between pre-release and this step, things should be fine.

***IMPORTANT***: [There is currently no way to remove an incorrectly tagged version of a Go module](https://github.com/golang/go/issues/34189).
It is critical you make sure the version you push upstream is correct.
[Failure to do so will lead to minor emergencies and tough to work around](https://github.com/open-telemetry/opentelemetry-go/issues/331).

1. For each module set that will be released, run the `add-tags` make target
    using the `<commit-hash>` of the commit on the main branch for the merged Pull Request.

    ```
    make add-tags MODSET=<module set> COMMIT=<commit hash>
    ```

    It should only be necessary to provide an explicit `COMMIT` value if the
    current `HEAD` of your working directory is not the correct commit.

2. Push tags to the upstream remote (not your fork: `github.com/open-telemetry/opentelemetry-go.git`).
    Make sure you push all sub-modules as well.

    ```
    git push upstream <new tag>
    git push upstream <submodules-path/new tag>
    ...
    ```

## Release

Finally create a Release for the new `<new tag>` on GitHub.
The release body should include all the release notes from the Changelog for this release.
Additionally, the `tag.sh` script generates commit logs since last release which can be used to supplement the release notes.

## Verify Examples

After releasing verify that examples build outside of the repository.

```
./verify_examples.sh
```

The script copies examples into a different directory removes any `replace` declarations in `go.mod` and builds them.
This ensures they build with the published release, not the local copy.

## Post-Release

### Contrib Repository

Once verified be sure to [make a release for the `contrib` repository](https://github.com/open-telemetry/opentelemetry-go-contrib/blob/main/RELEASING.md) that uses this release.

### Website Documentation

Update [the documentation](./website_docs) for [the OpenTelemetry website](https://opentelemetry.io/docs/go/).
Importantly, bump any package versions referenced to be the latest one you just released and ensure all code examples still compile and are accurate.
