sanic-json-logging 0.3.1

Simple library to emit json formatted logs to stdout

The other day I was running some containers on Amazon’s ECS and logging to cloudwatch. I then learnt cloudwatch parses JSON logs so obviously I then wanted Sanic to log out JSON.

Ideally this’ll be useful to people but if it isn’t, raise an issue and we’ll make it better :)

To install:

pip install sanic-json-logging

Look at examples/simple.py for a full working example, but this will essentially get you going

from sanic_json_logging import setup_json_logging, NoAccessLogSanic

app = NoAccessLogSanic('app1')
setup_json_logging(app)

The reason NoAccessLogSanic is used instead of Sanic is to disable the default access logger (it also disabled the LOGO).

setup_json_logging does the following:

• changes the default log formatters to JSON ones

• also filters out no Keepalive warnings

• unless told otherwise, will change the asyncio task factory, to implement some rudimentary task-local storage.

• installs pre and post request middleware. Pre-request middleware to time tasks and generate a uuid4 request id. Post-request middleware to emit access logs.

• will use AWS X-Forwarded-For IPs in the access logs if present

If setup_json_logging changed the task factory, all tasks created from the request’s task will contain the request ID.

Currently I have it outputting access logs like

{
  "timestamp": "2018-06-09T17:42:52.195701Z",
  "level": "INFO",
  "method": "GET",
  "path": "/endpoint1",
  "remote": "127.0.0.1:33468",
  "user_agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.62 Safari/537.36",
  "host": "localhost:8000",
  "response_time": 0.0,
  "req_id": "795617c7-b514-4ed9-bb63-cc4fcd883c3d",
  "logger": "sanic.access",
  "status_code": 200,
  "length": 0,
  "type": "access"
}

And if you log to the root logger, inside a request, it’ll look like this.

{
  "timestamp": "2018-06-09T17:42:52.195326Z",
  "level": "INFO",
  "message": "some informational message",
  "type": "log",
  "logger": "root",
  "filename": "simple.py",
  "lineno": 16,
  "req_id": "795617c7-b514-4ed9-bb63-cc4fcd883c3d"
}