Usage with FastAPI

Another example of usage with FastAPI - fastapi-sqlalchemy-template

1. Install lite-bootstrap[fastapi-all]:

=== "uv"

  ```bash
  uv add lite-bootstrap[fastapi-all]
  ```

=== "pip"

  ```bash
  pip install lite-bootstrap[fastapi-all]
  ```

=== "poetry"

  ```bash
  poetry add lite-bootstrap[fastapi-all]
  ```

Read more about available extras here.

2. Define bootstrapper config and build your application:

from lite_bootstrap import FastAPIConfig, FastAPIBootstrapper


bootstrapper_config = FastAPIConfig(
    service_name="microservice",
    service_version="2.0.0",
    service_environment="test",
    cors_allowed_origins=["http://test"],
    health_checks_path="/custom-health/",
    opentelemetry_endpoint="otl",
    prometheus_metrics_path="/custom-metrics/",
    sentry_dsn="https://testdsn@localhost/1",
    swagger_offline_docs=True,
)
bootstrapper = FastAPIBootstrapper(bootstrapper_config)
application = bootstrapper.bootstrap()

Read more about available configuration options here.

Logging

Structlog is configured process-wide, so structlog.get_logger() works in any route handler.

FastAPI has no access log of its own, so lite-bootstrap provides one. It is off by default, because uvicorn already writes an access line per request and an HTTP service is the highest-volume place to add a log record. Turn it on explicitly:

FastAPIConfig(
    service_name="microservice",
    fastapi_logging_middleware_enabled=True,
)

Enabled, it writes one http_request line per request to the http.access logger, carrying method, path, content_type, path_params and status_code under http, plus duration in nanoseconds. A request that raises is logged at exception level and the exception is re-raised unchanged.

Request and response bodies are never read or logged. path and path_params are, so a secret embedded in the URL itself (e.g. /reset-password/{token}) is recorded. Keep secrets in the request body.

These paths are skipped, whether or not the corresponding instrument is configured: swagger_path, swagger_static_path (when swagger_offline_docs is on), health_checks_path and prometheus_metrics_path. So if you disable health checks but still serve your own route at health_checks_path, that route is not access-logged either.

If you keep uvicorn's own access log as well, you will get two lines per request. To leave only the structured one, clear uvicorn's handlers:

FastAPIConfig(
    service_name="microservice",
    fastapi_logging_middleware_enabled=True,
    logging_unset_handlers=["uvicorn.access"],
)