12-factor-apps

# 12-Factor App Compliance Analysis > Reference: [The Twelve-Factor App](https://12factor.net) ## Overview The 12-Factor App methodology is a set of best practices for building Software-as-a-Service applications that are: - Portable across execution environments - Scalable without architectural changes - Suitable for continuous deployment - Maintainable with minimal friction ## Input Parameters | Parameter | Description | Required | |-----------|-------------|----------| | `codebase_path` | Root path of the codebase to analyze | Required | ## Analysis Framework ### Factor I: Codebase **Principle:** One codebase tracked in revision control, many deploys. **Search Patterns:** ```bash # Check for version control ls -la .git 2>/dev/null || ls -la .hg 2>/dev/null # Check for multiple apps sharing codebase find . -name "package.json" -o -name "pyproject.toml" -o -name "setup.py" | head -20 # Check for environment-specific code branches grep -r "if.*production\|if.*development\|if.*staging" --include="*.py" --include="*.js" --include="*.ts" ``` **File Patterns:** `.git/`, `package.json`, `pyproject.toml`, deployment configs **Compliance Criteria:** | Level | Criteria | |-------|----------| | **Strong** | Single Git repo, same codebase for all environments, no env-specific code branches | | **Partial** | Single repo but some environment-specific code paths | | **Weak** | Multiple repos for same app or significant code duplication across environments | **Anti-patterns:** - Multiple Git repositories for the same application - Environment-specific code branches (`if production: ...`) - Different source files for dev vs prod - Shared code not extracted to libraries --- ### Factor II: Dependencies **Principle:** Explicitly declare and isolate dependencies. **Search Patterns:** ```bash # Python dependency files find . -name "requirements.txt" -o -name "pyproject.toml" -o -name "setup.py" -o -name "Pipfile" -o -name "uv.lock" # JavaScript/TypeScript dependency files find . -name "package.json" -o -name "package-lock.json" -o -name "yarn.lock" -o -name "pnpm-lock.yaml" # Check for system tool assumptions grep -r "subprocess.*curl\|subprocess.*wget\|os.system.*ffmpeg\|shutil.which" --include="*.py" grep -r "exec.*curl\|child_process.*curl" --include="*.js" --include="*.ts" # Docker/container isolation find . -name "Dockerfile" -o -name "docker-compose*.yml" ``` **File Patterns:** `**/requirements*.txt`, `**/package.json`, `**/*.lock`, `**/Dockerfile` **Compliance Criteria:** | Level | Criteria | |-------|----------| | **Strong** | Lock files present, dependency isolation (venv/Docker), no implicit system tools | | **Partial** | Dependencies declared but no lock files or isolation | | **Weak** | Dependencies in documentation only, relies on system-installed packages | **Anti-patterns:** - Missing lock files (non-deterministic builds) - Assuming system tools (curl, ImageMagick, ffmpeg) are available - Different dependency managers in dev vs production - No virtual environment or container isolation --- ### Factor III: Config **Principle:** Store config in the environment. **Search Patterns:** ```bash # Environment variable usage grep -r "os.environ\|os.getenv\|process.env\|ENV\[" --include="*.py" --include="*.js" --include="*.ts" --include="*.rb" # Hardcoded credentials (anti-pattern) grep -r "password.*=.*['\"]" --include="*.py" --include="*.js" --include="*.ts" | grep -v "test\|spec\|example" grep -r "api_key.*=.*['\"]" --include="*.py" --include="*.js" --include="*.ts" | grep -v "test\|spec\|example" grep -r "secret.*=.*['\"]" --include="*.py" --include="*.js" --include="*.ts" | grep -v "test\|spec\|example" # Environment-specific config files (anti-pattern) find . -name "config.dev.*" -o -name "config.prod.*" -o -name "settings.development.*" -o -name "settings.production.*" # Database URLs in code grep -r "postgresql://\|mysql://\|mongodb://\|redis://" --include="*.py" --include="*.js" --include="*.ts" | grep -v ".env\|test\|example" ``` **File Patterns:** `**/.env*`, `**/config/*.py`, `**/settings.py`, environment files **Compliance Criteria:** | Level | Criteria | |-------|----------| | **Strong** | All config via environment variables, no hardcoded secrets, could open-source without leaks | | **Partial** | Most config externalized but some hardcoded defaults | | **Weak** | Hardcoded credentials, environment-specific config files | **Anti-patterns:** - Hardcoded database URLs, API keys, passwords in source - Config files like `config/production.yml` vs `config/development.yml` - Environment grouping (`if ENV == 'production': ...`) - Secrets committed to version control --- ### Factor IV: Backing Services **Principle:** Treat backing services as attached resources. **Search Patterns:** ```bash # Database connection via config grep -r "DATABASE_URL\|DB_HOST\|REDIS_URL\|CACHE_URL" --include="*.py" --include="*.js" --include="*.ts" # Service initialization grep -r "create_engine\|MongoClient\|Redis\|Celery\|boto3" --include="*.py" grep -r "createPool\|createClient\|new Redis\|S3Client" --include="*.js" --include="*.ts" # Hardcoded service locations (anti-pattern) grep -r "localhost:5432\|localhost:6379\|localhost:27017\|127.0.0.1" --include="*.py" --include="*.js" --include="*.ts" | grep -v "test\|spec\|example\|default" ``` **File Patterns:** `**/database/*.py`, `**/services/*.py`, `**/db.py`, connection configurations **Compliance Criteria:** | Level | Criteria | |-------|----------| | **Strong** | All services via URL/connection string in config, swappable without code changes | | **Partial** | Most services configurable but some hardcoded defaults | | **Weak** | Hardcoded service locations, different code paths per environment | **Anti-patterns:** - Hardcoded `localhost` for services in production code - Conditional logic for local vs cloud services (`if USE_S3: ... else: local_storage`) - Service-specific code paths based on environment - Different drivers for dev vs prod --- ### Factor V: Build, Release, Run **Principle:** Strictly separate build and run stages. **Search Patterns:** ```bash # Build/deploy configuration find . -name "Dockerfile" -o -name "Makefile" -o -name "build.sh" -o -name "deploy.sh" find . -name ".github/workflows/*.yml" -o -name ".gitlab-ci.yml" -o -name "Jenkinsfile" # Build scripts in package.json grep -A5 '"scripts"' package.json 2>/dev/null | grep -E "build|start|deploy" # Check for runtime compilation (anti-pattern) grep -r "compile\|transpile\|webpack" --include="*.py" | grep -v "test\|build" ``` **File Patterns:** `**/Dockerfile`, `**/Makefile`, `**/.github/workflows/**`, CI/CD configs **Compliance Criteria:** | Level | Criteria | |-------|----------| | **Strong** | Immutable releases, clear build/release/run stages, unique release IDs | | **Partial** | Build and run separated but release not immutable | | **Weak** | Runtime code modifications, asset compilation at startup | **Anti-patterns:** - Runtime code modifications - Asset compilation during application startup - Configuration baked into build artifacts - No release versioning --- ### Factor VI: Processes **Principle:** Execute the app as one or more stateless processes. **Search Patterns:** ```bash # Session storage patterns grep -r "session\|Session" --include="*.py" --include="*.js" --include="*.ts" | head -20 # In-process state (anti-pattern) grep -r "global.*cache\|process_local\|instance_cache" --include="*.py" grep -r "global\..*=\|module\.exports\.cache" --include="*.js" --include="*.ts" # External session stores (good pattern) grep -r "redis.*session\|memcached.*session\|session.*redis" --include="*.py" --include="*.js" --include="*.ts" # Sticky session configuration (anti-pattern) grep -r "sticky.*session\|session.*affinity" --include="*.yml" --include="*.yaml" --include="*.json" ``` **File Patterns:** `**/middleware/*.py`, `**/session/*.py`, server configurations **Compliance Criteria:** | Level | Criteria | |-------|----------| | **Strong** | Stateless processes, all state in external datastores (Redis, DB) | | **Partial** | Mostly stateless but some in-process caching | | **Weak** | Sticky sessions, in-process session storage, shared memory state | **Anti-patterns:** - In-process session storage (`user_sessions = {}`) - Sticky sessions or session affinity - File-based caching between requests - Global mutable state shared across requests --- ### Factor VII: Port Binding **Principle:** Export services via port binding. **Search Patterns:** ```bash # Self-contained port binding grep -r "app.run\|server.listen\|serve\|uvicorn" --include="*.py" grep -r "app.listen\|server.listen\|createServer" --include="*.js" --include="*.ts" # PORT environment variable grep -r "PORT\|port" --include="*.py" --include="*.js" --include="*.ts" | grep -i "environ\|process.env" # Webserver as dependency