Add AGENTS.md

Signed-off-by: Lennart Jern <[email protected]>

Author: lentzi90

AGENTS.md

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+# AGENTS.md - Agent Guidelines for Cluster API Provider OpenStack
+
+This document provides guidelines and useful commands for AI agents contributing to the Cluster API Provider OpenStack (CAPO) repository.
+
+> **⚠️ IMPORTANT**: When making changes to Makefile targets, PR requirements, code generation workflows, verification steps, or any other information referenced in this document, **AGENTS.md must be updated accordingly** to keep it synchronized with the actual project state.
+
+## Overview
+
+Cluster API Provider OpenStack (CAPO) is a Kubernetes-native declarative infrastructure provider for managing Kubernetes clusters on OpenStack. It implements the Cluster API (CAPI) specification for self-managed Kubernetes clusters on OpenStack infrastructure.
+
+**Key Concepts:**
+- **CAPI**: Cluster API - the upstream Kubernetes project defining cluster lifecycle APIs
+- **CAPO**: Cluster API Provider OpenStack - this repository
+- **Reconciler**: Controller-runtime pattern for managing Kubernetes custom resources
+- **Scope**: Context and configuration wrapper for controllers and services
+
+## Key Requirements for Contributors
+
+### Legal Requirements
+
+- **CLA Required**: All contributors MUST sign the Kubernetes Contributor License Agreement (CLA)
+- See: https://git.k8s.io/community/CLA.md
+
+### Pull Request Labels
+
+All code PRs MUST be labeled with one of:
+- ⚠️ `:warning:` - major or breaking changes
+- ✨ `:sparkles:` - feature additions
+- 🐛 `:bug:` - patch and bugfixes
+- 📖 `:book:` - documentation or proposals
+- 🌱 `:seedling:` - minor or other
+
+## Essential Make Targets
+
+### Code Quality & Verification
+
+```bash
+# Run all verification checks (should pass before submitting PR)
+make verify
+
+# Verify boilerplate headers
+make verify-boilerplate
+
+# Verify go modules are up to date
+make verify-modules
+
+# Verify generated code is up to date
+make verify-gen
+
+# Verify container images for vulnerabilities
+make verify-container-images
+
+# Check code for security vulnerabilities
+make verify-govulncheck
+
+# Run all security checks (images + code)
+make verify-security
+```
+
+### Linting
+
+```bash
+# Lint codebase
+make lint
+
+# Lint and auto-fix issues
+make lint-update
+
+# Run faster linters only
+make lint-fast
+```
+
+### Testing
+
+```bash
+# Run unit tests
+make test
+
+# Run unit tests for CAPO specifically
+make test-capo
+
+# Build e2e test binaries
+make build-e2e-tests
+
+# Run e2e tests (requires OpenStack environment)
+make test-e2e
+
+# Run conformance tests
+make test-conformance
+
+# Compile e2e tests (verify they build)
+make compile-e2e
+```
+
+### Code Generation
+
+```bash
+# Generate ALL code (manifests, deepcopy, clients, mocks, docs)
+make generate
+
+# Generate Go code (mocks, etc.)
+make generate-go
+
+# Generate controller-gen code (deepcopy, etc.)
+make generate-controller-gen
+
+# Generate client code (clientsets, listers, informers)
+make generate-codegen
+
+# Generate CRD manifests
+make generate-manifests
+
+# Generate API documentation
+make generate-api-docs
+
+# Generate cluster templates
+make templates
+```
+
+### Dependency Management
+
+```bash
+# Update go modules
+make modules
+
+# Check for API differences (useful before breaking changes)
+make apidiff
+```
+
+### Building
+
+```bash
+# Build manager binaries
+make managers
+
+# Build all binaries
+make binaries
+
+# Build Docker image
+make docker-build
+
+# Build debug Docker image
+make docker-build-debug
+
+# Build for all architectures
+make docker-build-all
+```
+
+### Cleanup
+
+```bash
+# Clean all build artifacts
+make clean
+
+# Clean binaries only
+make clean-bin
+
+# Clean temporary files
+make clean-temporary
+
+# Clean release artifacts
+make clean-release
+```
+
+## Important Development Patterns
+
+### Adding New OpenStack Resources
+
+1. Define API types in `/api/v1beta1` (or `/api/v1alpha1` for experimental features)
+2. Run `make generate` to create deepcopy methods and update CRDs
+3. Create controller in `/controllers`
+4. Create service implementation in `/pkg/cloud/services/<category>`
+5. Update or create scope in `/pkg/scope` if needed
+6. Add webhooks in `/pkg/webhooks` for validation/defaulting
+7. Add unit tests for controller and services
+8. Update documentation
+9. Generate cluster templates if applicable with `make templates`
+
+### Testing Strategy
+
+1. **Unit Tests**: Test individual functions/methods with mocks
+2. **Integration Tests**: Test controller behavior with envtest
+3. **E2E Tests**: Deploy real clusters on OpenStack, verify functionality
+4. **Conformance Tests**: Run upstream Kubernetes conformance suite
+
+## Pre-Submit Checklist for Agents
+
+Before submitting a PR, ensure:
+
+1. **Code is generated and up to date**:
+   ```bash
+   make generate
+   ```
+
+2. **Modules are tidy**:
+   ```bash
+   make modules
+   ```
+
+3. **Code passes linting**:
+   ```bash
+   make lint
+   ```
+
+4. **Tests pass**:
+   ```bash
+   make test
+   ```
+
+5. **All verification checks pass**:
+   ```bash
+   make verify
+   ```
+
+## Common Workflows
+
+### Making Code Changes
+
+1. Make your code changes
+2. Run code generation: `make generate`
+3. Update modules if needed: `make modules`
+4. Run tests: `make test`
+5. Lint the code: `make lint`
+6. Verify everything: `make verify`
+7. Commit changes with descriptive message
+
+### Updating Dependencies
+
+1. Update `go.mod` or `hack/tools/go.mod` as needed
+2. Run: `make modules`
+3. Run: `make verify-modules`
+4. Test that everything still works: `make test`
+
+## Common Issues
+
+### Linting Errors
+
+The project uses golangci-lint. If you get lint errors:
+1. Run `make lint-update` first to auto-fix
+2. Check `.golangci.yml` for enabled linters
+3. Some issues require manual fixes (cognitive complexity, error handling, etc.)
+4. Don't disable linters without good reason - fix the underlying issue
+
+### Test Failures
+
+- **envtest issues**: Ensure KUBEBUILDER_ASSETS is set correctly
+- **Flaky E2E tests**: Transient infrastructure issues, failure to deploy devstack
+
+### Generated File Drift
+
+If `make verify` fails with generated file drift:
+1. Run `make generate` to regenerate all files
+2. Review the changes to ensure they're expected
+3. Commit the generated files
+4. Never manually edit generated files
+
+## Documentation
+
+Primary documentation is in `/docs/book/src/` (mdBook format):
+- Getting started guides
+- Developer documentation
+- Troubleshooting guides
+- API reference
+- Cluster template documentation
+
+Build and serve docs locally:
+```bash
+make -C docs/book serve
+```
+
+## Quick Reference
+
+| Task | Command |
+|------|---------|
+| Full verification before PR | `make verify && make test` |
+| Generate all code | `make generate` |
+| Update dependencies | `make modules` |
+| Lint and fix | `make lint-update` |
+| Run tests | `make test` |
+| Build binary | `make managers` |
+| Build Docker image | `make docker-build` |
+| Clean everything | `make clean` |
+| Check API compatibility | `make apidiff` |
+| Generate templates | `make templates` |
+| Build and serve docs | `make -C docs/book serve` |