ESGI

ESGI (Event-based Server Gateway Interface) is a sync gateway for HTTP and WebSocket: one call per connection, a scope, and a blocking protocol object — no ASGI receive/send loop. Spec: PROTOCOL.md (0.1-draft).

Config

module_esgi always runs a gevent worker (runtime gevent, the default). Install gevent in the app environment.

python {
    module_esgi "main:application"
    runtime gevent
    venv "./venv"
    workers 4
}

Exactly one of module_wsgi, module_asgi, or module_esgi per block. Optional __esgi_init__ / __esgi_del__ hooks run at worker start/shutdown. Prefer __esgi__(self, scope, protocol) when present.

Runtime defaults

Interface	Allowed runtime	Default
WSGI	sync, gevent	sync
ESGI	gevent only	gevent
ASGI	native, uvloop	uvloop

ASGI uvloop falls back to native asyncio if uvloop is not installed. Legacy libuv is normalized to uvloop.

Coverage today

• HTTP: read_body, iter_body, response_empty / response_str / response_bytes, response_file, response_file_range
• WebSocket: accept → WsTransport (receive / send_bytes / send_str); RFC 6455 close
• Not yet: response_stream / full streaming refinements

Integration test: ./tests/integration.sh simple_esgi 3.13.