Bazel Multi-Language Monorepo Example

This is a unified mono repo example that demonstrates how to develop, build, test, and deploy full-stack web projects, infrastructure code, and build tools using Bazel. It is designed for scalability, fast builds, and optimized deployment.

Main Features:

1. Repo package managers:
   • PNPM;
   • PYPI;
2. Programming languages support:
   • TypeScript / JavaScript (Aspect's rules_ts);
     • Building:
       • Root package.json support for references across all projects;
       • Build internal packages;
       • Build external packages (PNPM package manager support);
       • TSC TypeScript transpiler support;
       • SWC TypeScript transpiler support (faster TSC alternative);
       • Bundling support:
         • Webpack support;
         • ESbuild support;
         • RSPack support (Webpack drop in replacement);
         • Vite support;
       • SCSS-styles support;
         • "use" imports support;
       • Static assets support;
         • Image support example;
         • JSON files support example;
     • Testing:
       • Tests spec files separation from the source code in Bazel (:tsc and :tsc_tests are separate);
       • Tests coverage;
       • Mocha/Chai support;
       • Vitest support;
     • Developing:
       • Run local dev server (Webpack);
       • Run local dev server (RSpack);
   • Python (Aspect's rules_py);
     • Building:
       • Build internal packages;
       • Build external packages (PYPI package manager support);
     • Testing:
       • Tests support;
       • Tests coverage;
   • GoLang;
     • Building:
       • Build internal packages;
       • Build external packages (go_dependency support);
     • Testing:
       • Tests support;
       • Tests coverage;
3. Formatting:
   • Ruff —> Python;
   • Prettier —> JS, TS, HTML, CSS, SCSS, SQL, Markdown;
   • Yamlfmt —> Yaml;
   • Buildifier —> Starlark;
   • Gofumpt —> Go;
   • SHFMT —> shell/bash scripts;
   • Terraform —> Terraform;
4. Linting:
   • Eslint V9 (flat config format) —> JS, JSX, TS, TSX, CJS, MJS. (commit);
   • Stylint —> CSS, SCSS (commit);
   • Flake8 —> Py (commit);
   • Shellcheck —> shell/bash scripts (commit);
5. Development:
   • Add Remote Cache Execution support with BuildBuddy;
   • Add watcher IBazel to re-build targets on source files change (instruction);
   • Add custom Bazel rules examples:
     • Simple Bazel rule example of creating a file in bazel-bin (commit);
     • Simple Bazel rule example of using a dependency rule (commit);
     • Simple Bazel rule example of using external (Go-app) binary (commit);
     • Simple Bazel rule example of writing back to the source of the project workspace (commit);
   • Auto-generate documentation;
   • Use Gazelle to auto-update BUILD files;
   • Custom scripts:
     • New bazel command to create a new project using a template;
6. CI/CD integration:
   • Renovate bot support to update monorepo dependencies;
   • Add dependencies review for PRs (license, Vulnerabilities, denied, etc...);
   • Use local CI cache to store Bazel artifacts;
   • Build all targets;
   • Run all tests;
   • Run format check;
   • Run lint check;
7. Infra:
   • Docker: create image;
   • Docker: push image to registry;
   • K8s: generate manifests with concat;
   • K8s: generate manifests with helm;
   • K8s: manual manifests deploy;
   • K8s: gitops manifests deploy;
   • Terraform: run plan;
   • Terraform: update cloud manifest;

Main Commands:

Bazel:

• $ bazel build ... — build all targets in the repo.
• $ bazel test ... — test all (testable) targets in the repo.
  • $ bazel test --test_output=all ... - to see tests output in cli.
• $ bazel coverage ... - generate tests coverage.
  • $ bazel coverage --combined_report=lcov --test_output=all ... - to see tests output + tests coverage files (in coverage.dat).
• $ bazel lint ... - lint all projects.
  • $ bazel lint ... --fix - lint fix all projects.
  • $ bazel lint //experimental/service_test_ts_webpack_react_tests/... — lint individual project.

PNPM (for TS/JS):

• $ pnpm update - update all projects in the monorepo.
• $ pnpm install - install all npm deps for all projects in monorepo.
• $ pnpm add — install package in some project (required $cd into it, example: $ pnpm add typescript --save-dev).
• $ pnpm run — run script in package.json (example $ pnpm run build).

PYPI (for Python):

Manual dependencies update in monorepo (including transitive dependencies).

• Use requirements.in file to manage (install new, update or remove old) Python dependencies in the entire monorepo.
• $ bazel run //:generate_requirements_txt - run to update requirements.txt automatically.

Repo maintenance:

• $ bazel fetch //... — fetches all external dependencies required for building all targets in your workspace. Note: It does this without actually building them.
• $ bazel fetch @npm//... — update Bazel's copy of pnpm lockfile. Useful after adding new NPM packages.
• $ bazel mod tidy — (analog of bazel sync in WORKSPACE) sync / check the status of dependencies in MODULES.
• $ bazel run format — formats everything in the repo.
  • $ bazel run //:format — formats everything in the repo (explicit run from the root).
  • $ bazel run //:format.check — check if formatting needs to be applied.
• $ bazel lint ... — lints all projects.
  • $ bazel lint //experimental/service_test_ts_webpack_react_tests/... — lints individual project.

Secrets:

• BUILD_BUDDY_API_KEY - auth account key for BuildBuddy remote execution UI.
  • For CI use, it's stored in: repo > settings > secrets > actions > BUILD_BUDDY_API_KEY key.
  • Create a free personal account on BuildBuddy to get this key.

Other documents:

• Intro;
• Create monorepo - step-by-step guide;
• Bazel troubleshooting ;
• Bazel training ;