Add BCR GitHub workflow and configuration

Author: Copilot

.bcr/README.md

@@ -0,0 +1,58 @@
+# BCR Publishing Configuration
+
+This directory contains the template files required for publishing opentelemetry-cpp to the [Bazel Central Registry (BCR)](https://github.com/bazelbuild/bazel-central-registry).
+
+## Files
+
+### metadata.template.json
+Contains the module metadata including homepage, maintainers, and repository information. This is used to create/update the BCR metadata for the module.
+
+### source.template.json
+Defines the source archive location and format. Placeholders like `{OWNER}`, `{REPO}`, `{TAG}`, and `{VERSION}` are automatically replaced during publishing.
+
+### presubmit.yml
+Defines the BCR presubmit tests that run when a new version is published. Currently configured to test on:
+- Platforms: debian10, macos, ubuntu2004, windows
+- Bazel versions: 7.x, 8.x, 9.*
+
+## Publishing Process
+
+The publish-to-bcr workflow (`.github/workflows/publish-to-bcr.yml`) automates publishing to BCR.
+
+### Prerequisites
+
+**Create a Personal Access Token (PAT)**:
+   - Create a Classic PAT with `workflow` and `repo` permissions
+   - Add it as a secret named `BCR_PUBLISH_TOKEN` in repository settings
+
+### How to Publish
+
+The workflow can be triggered in two ways:
+
+1. **Automatically**: When a new GitHub release is published
+2. **Manually**: Via workflow dispatch in GitHub Actions UI
+   - Go to Actions → Publish to BCR → Run workflow
+   - Enter the tag name (e.g., `v1.24.0`)
+
+### What Happens
+
+When triggered, the workflow:
+1. Generates a BCR entry using these templates
+2. Pushes the entry to your BCR fork
+3. Opens a pull request against the upstream BCR
+
+### Using a Fork Registry
+
+For development and testing, you can use a fork of the Bazel Central Registry:
+
+1. Fork https://github.com/bazelbuild/bazel-central-registry
+2. Configure your fork URL in the workflow (modify the `publish-to-bcr.yml` file)
+3. Test changes in your fork before submitting to the official BCR
+
+The configuration in this repository points to the **official** Bazel Central Registry at https://github.com/bazelbuild/bazel-central-registry. However, using a fork registry is recommended for testing and development to avoid polluting the official registry during experimentation.
+
+## References
+
+- [Publish to BCR Action](https://github.com/bazel-contrib/publish-to-bcr)
+- [Bazel Central Registry](https://github.com/bazelbuild/bazel-central-registry)
+- [BCR Module: opentelemetry-cpp](https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/opentelemetry-cpp)

.bcr/metadata.template.json

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+{
+  "homepage": "https://github.com/open-telemetry/opentelemetry-cpp",
+  "maintainers": [
+    {
+      "name": "Keith Smiley",
+      "email": "[email protected]",
+      "github": "keith",
+      "github_user_id": 283886
+    },
+    {
+      "name": "Marc Alff",
+      "email": "[email protected]",
+      "github": "marcalff",
+      "github_user_id": 17238896
+    }
+  ],
+  "repository": [
+    "github:open-telemetry/opentelemetry-cpp"
+  ],
+  "versions": [],
+  "yanked_versions": {}
+}

.bcr/presubmit.yml

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+matrix:
+  platform: ["debian10", "macos", "ubuntu2004", "windows"]
+  bazel: ["7.x", "8.x", "9.*"]
+tasks:
+  verify_targets:
+    platform: ${{ platform }}
+    bazel: ${{ bazel }}
+    build_flags:
+    - '--cxxopt=-std=c++14'
+    - '--host_cxxopt=-std=c++14'
+    build_targets:
+    - '@opentelemetry-cpp//api'

.bcr/source.template.json

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+{
+  "integrity": "",
+  "strip_prefix": "opentelemetry-cpp-{VERSION}",
+  "url": "https://github.com/{OWNER}/{REPO}/archive/refs/tags/{TAG}.tar.gz"
+}

.github/workflows/publish-to-bcr.yml

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+name: Publish to BCR
+
+on:
+  # Allow manual triggering for testing and recovery
+  workflow_dispatch:
+    inputs:
+      tag_name:
+        description: 'Tag name to publish (e.g., v1.24.0)'
+        required: true
+        type: string
+  # Automatically trigger after a release is created
+  release:
+    types: [published]
+
+jobs:
+  publish:
+    permissions:
+      contents: write
+    uses: bazel-contrib/publish-to-bcr/.github/workflows/[email protected]
+    with:
+      tag_name: ${{ inputs.tag_name || github.event.release.tag_name }}
+      attest: false
+    secrets:
+      publish_token: ${{ secrets.BCR_PUBLISH_TOKEN }}

README.md

@@ -60,6 +60,17 @@ license requirements.
 
 Please refer to [INSTALL.md](./INSTALL.md).
 
+### Bazel Central Registry
+
+This project is available in the [Bazel Central Registry (BCR)](https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/opentelemetry-cpp).
+To use it with Bazel, add the following to your `MODULE.bazel` file:
+
+```python
+bazel_dep(name = "opentelemetry-cpp", version = "x.y.z")
+```
+
+For the latest version, see [BCR: opentelemetry-cpp](https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/opentelemetry-cpp).
+
 ## Getting Started
 
 As an application owner or the library author, you can find the getting started