timing-asgi middleware example

This repository contains a tiny starlette ASGI application, to demonstrate how the timing-asgi middleware can be used to automatically instrument routes in an ASGI application and emit timing metrics, for example to datadog via statsd.

setup

$ make run
...
Successfully installed alog-0.9.13 certifi-2018.11.29 chardet-3.0.4 click-7.0 datadog-0.27.0 decorator-4.3.2 h11-0.8.1 httptools-0.0.13 idna-2.8 requests-2.21.0 starlette-0.11.3 timing-asgi-0.1.0rc1 urllib3-1.24.1 uvicorn-0.5.1 uvloop-0.12.1 websockets-7.0
venv/bin/python app.py
INFO: Started server process [24774]
INFO: Waiting for application startup.
2019-03-07 09:40:24 INFO  [timing_asgi.middleware:44] ASGI scope of type lifespan is not supported yet
INFO: Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO: ('127.0.0.1', 54016) - "GET / HTTP/1.1" 200

see in action

If you're like me, you'd like to see something being emitted, which is easy to do with netcat:

Keep the server running from the step above, then open two shells.

In the first run:

$ nc -ul 8125

In the second run:

$ curl http://127.0.0.1:8000/

If for some reason your app server isn't listening on 127.0.0.1:8000 replace the value above with the one reported by uvicorn when running the app initially.

This curl command when successful will cause the nc shell to print out the raw statsd data it collected on port 8125:

myapp.__main__.homepage:0.001255035400390625|ms|#http_status:200,http_method:GET,time:wall,app_version:myapp.__main__.homepage:0.0010529999999999706|ms|#http_status:200,http_method:GET,time:cpu,app_version: