bcr-frontend

This repository provides a web UI and API for the Bazel Central Registry.

• A git submodule is located at data/bazel-central-registry.
• A custom gazelle extension //language/bcr walks the module tree under data/bazel-central-registry/modules, creating a set of build rules that represent the state of the registry. The various modules and module versions are linked into a top-level module_registry rule //data/bazel-central-registry/modules:modules. A makefile target make bcr can be run locally that checks out the most recent version of the submodule and runs the gazelle extension.
  • NOTE: GITHUB_TOKEN is required for fetching repository metadata during a gazelle run.
• A protobuf representation of the state of the BCR is constructed by bazel build //data/bazel-central-registry/modules:modules. This includes downloading source repository archives for latest versions (that include starlark files) and extracting stardoc for them, outputting the file bazel-bin/data/bazel-central-registry/modules/registry.pb.
• bazel run //app/bcr:release builds the frontend single-page-application UI and embed the registry proto data in it, and starts a webserver for local development.
• bazel //app/api builds a rust->wasm app that runs as a cloudflare worker to service API requests. The UI does not currently depend on the API; the primary purpose is to support shields.io-like badges (example: ). The API also serves fragments of the Registry protobuf data.
• bazel run //app/bcr:deploy builds the UI and API and deploys it to cloudflare.

CI works as follows:

• When new commits land in github.com/bazelbuild/bazel-central-registry, a repository dispatch triggers trigger-via-bcr.yml, which directly deploys to production without creating commits or PRs on main.
• A weekly cron job (periodic-submodule-sync.yaml) syncs the main branch's submodule reference to keep it reasonably current.

Manual Deployment

To manually deploy a specific BCR commit:

gh workflow run trigger-via-bcr.yml -f bcr_commit=<sha>

To deploy the latest BCR commit:

gh workflow run trigger-via-bcr.yml

Build Pipeline

graph TB
    subgraph "Data Sources"
        BCR[bazel-central-registry<br/>git submodule]
        GH[GitHub API<br/>Repository Metadata]
    end

    subgraph "Gazelle Extension: //language/bcr"
        BCR --> Parse[Parse Modules]
        Parse --> GenRules[Generate Bazel Rules]
        GenRules --> FetchMeta[Fetch Repository Metadata]
        GH --> FetchMeta
        FetchMeta --> ModMeta[module_metadata rules]
        FetchMeta --> ModVer[module_version rules]
        FetchMeta --> ModReg[module_registry rule]
    end

    subgraph "Documentation Pipeline"
        ModVer --> DownloadArchives[Download http_archive<br/>for latest versions]
        DownloadArchives --> ExtractBzl[Extract .bzl files]
        ExtractBzl --> GenDocs[Generate Documentation<br/>Starlark symbols]
        GenDocs --> DocProto[documentation_registry.pb]
    end

    subgraph "Build Artifacts: //app/bcr:release"
        ModReg --> RegProto[registry.pb<br/>~6MB compressed]
        DocProto --> RegProto
        RegProto --> Embed[Embed into SPA]
        JS[bcr.js<br/>Closure-compiled] --> Embed
        CSS[bcr.css<br/>Styles] --> Embed
        HTML[index.html] --> Embed
        Assets[favicon.png, sitemap.xml, robots.txt] --> Embed
        Embed --> ReleaseTar[release.tar]
    end

    subgraph "Deployment"
        ReleaseTar --> Deploy[cloudflare_deploy<br/>deploy assets]
        Deploy --> Live[https://bcr.stack.build]
    end

    %% Data Sources - Light Blue with darker borders
    style BCR fill:#bbdefb,stroke:#1976d2,stroke-width:2px,color:#000
    style GH fill:#bbdefb,stroke:#1976d2,stroke-width:2px,color:#000

    %% Gazelle Extension - Light Purple
    style Parse fill:#e1bee7,stroke:#7b1fa2,stroke-width:2px,color:#000
    style GenRules fill:#e1bee7,stroke:#7b1fa2,stroke-width:2px,color:#000
    style FetchMeta fill:#e1bee7,stroke:#7b1fa2,stroke-width:2px,color:#000
    style ModMeta fill:#e1bee7,stroke:#7b1fa2,stroke-width:2px,color:#000
    style ModVer fill:#e1bee7,stroke:#7b1fa2,stroke-width:2px,color:#000
    style ModReg fill:#e1bee7,stroke:#7b1fa2,stroke-width:2px,color:#000

    %% Documentation Pipeline - Light Orange
    style DownloadArchives fill:#ffccbc,stroke:#e64a19,stroke-width:2px,color:#000
    style ExtractBzl fill:#ffccbc,stroke:#e64a19,stroke-width:2px,color:#000
    style GenDocs fill:#ffccbc,stroke:#e64a19,stroke-width:2px,color:#000
    style DocProto fill:#ffe082,stroke:#f57f17,stroke-width:3px,color:#000

    %% Build Artifacts - Light Green
    style RegProto fill:#ffe082,stroke:#f57f17,stroke-width:3px,color:#000
    style Embed fill:#c5e1a5,stroke:#558b2f,stroke-width:2px,color:#000
    style JS fill:#c5e1a5,stroke:#558b2f,stroke-width:2px,color:#000
    style CSS fill:#c5e1a5,stroke:#558b2f,stroke-width:2px,color:#000
    style HTML fill:#c5e1a5,stroke:#558b2f,stroke-width:2px,color:#000
    style Assets fill:#c5e1a5,stroke:#558b2f,stroke-width:2px,color:#000
    style ReleaseTar fill:#aed581,stroke:#33691e,stroke-width:4px,color:#000

    %% Deployment - Light Teal
    style Deploy fill:#b2dfdb,stroke:#00695c,stroke-width:2px,color:#000
    style Live fill:#80cbc4,stroke:#004d40,stroke-width:4px,color:#000

Loading

Maintenance and Support

This repo is funded by contributions to our OpenCollective. Maintenance is performed on a best-effort basis by volunteers in the Bazel community.

Contributing

We are happy about any contributions!

To get started you can take a look at our Github issues.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be licensed as below, without any additional terms or conditions.

Quick Start

Have a GITHUB_TOKEN available (for rate limit increases):

$ export GITHUB_TOKEN=ghp_...

Step 1: initialize (or update) the bcr submodule:

$ make bcr_init
$ make bcr_update

Step 2: run the gazelle extension over it (with GITHUB_TOKEN):

$ bazel run bcr

Step 3: build and run a development server over the release assets (consider ibazel for iterative development):

$ bazel run //app/bcr:release
...
releaseserver: Starting server on http://localhost:8080
releaseserver: Press Ctrl+C to stop