The little ASGI framework that shines. 🌟
✨ The little ASGI framework that shines. ✨
Documentation: https://www.starlette.io/
Community: https://discuss.encode.io/c/starlette
Starlette is a lightweight ASGI framework/toolkit, which is ideal for building high performance asyncio services.
It is production-ready, and gives you the following:
requests.
Python 3.6+
$ pip3 install starlette
You'll also want to install an ASGI server, such as uvicorn, daphne, or hypercorn.
$ pip3 install uvicorn
example.py:
from starlette.applications import Starlette from starlette.responses import JSONResponse from starlette.routing import Routeasync def homepage(request): return JSONResponse({'hello': 'world'})
routes = [ Route("/", endpoint=homepage) ]
app = Starlette(debug=True, routes=routes)
Then run the application using Uvicorn:
$ uvicorn example:app
For a more complete example, see encode/starlette-example.
Starlette does not have any hard dependencies, but the following are optional:
requests- Required if you want to use the
TestClient.
aiofiles- Required if you want to use
FileResponseor
StaticFiles.
jinja2- Required if you want to use
Jinja2Templates.
python-multipart- Required if you want to support form parsing, with
request.form().
itsdangerous- Required for
SessionMiddlewaresupport.
pyyaml- Required for
SchemaGeneratorsupport.
graphene- Required for
GraphQLAppsupport.
You can install all of these with
pip3 install starlette[full].
Starlette is designed to be used either as a complete framework, or as an ASGI toolkit. You can use any of its components independently.
from starlette.responses import PlainTextResponseasync def app(scope, receive, send): assert scope['type'] == 'http' response = PlainTextResponse('Hello, world!') await response(scope, receive, send)
Run the
appapplication in
example.py:
$ uvicorn example:app INFO: Started server process [11509] INFO: Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
Run uvicorn with
--reloadto enable auto-reloading on code changes.
The modularity that Starlette is designed on promotes building re-usable components that can be shared between any ASGI framework. This should enable an ecosystem of shared middleware and mountable applications.
The clean API separation also means it's easier to understand each component in isolation.
Independent TechEmpower benchmarks show Starlette applications running under Uvicorn as one of the fastest Python frameworks available. (*)
For high throughput loads you should:
uvicornworker class.
Eg.
gunicorn -w 4 -k uvicorn.workers.UvicornWorker --log-level warning example:app
Several of the ASGI servers also have pure Python implementations available, so you can also run under
PyPyif your application code has parts that are CPU constrained.
Either programatically:
uvicorn.run(..., http='h11', loop='asyncio')
Or using Gunicorn:
gunicorn -k uvicorn.workers.UvicornH11Worker ...
— ⭐️ —
Starlette is BSD licensed code. Designed & built in Brighton, England.