lat stands for latency, i think it's roughly describing what you wanna. If you are using gunicorn, you can get that from access log for free. You may also get that from your reverse proxy layer if you have one.
Can I re-open this issue? I want to log latency as part of my access logs, but doesn't seem like I can right now because:
It doesn't seem like the Gunicorn worker does access logging -- I have tried a number of logging configurations and Gunicorn remains silent. The built-in Gunicorn workers all contain calls to self.log.access which are missing from sanic.worker.GunicornWorker so I'm not sure if we get it for free that way (@yunstanford ?)
There is no straightforward way to override the log call in sanic.server.HttpProtocol.log_response in order to add additional fields (for example, request['spent_time']
It doesn't seem entirely straightforward to add response time taken to just the worker, as its response handling is dealt with elsewhere...