request_logger.py

import datetime
import time

import colors
from flask import g, request
from rfc3339 import rfc3339


def attach_logger(app):

    @app.before_request
    def start_timer():
        g.start = time.time()

    @app.after_request
    def log_request(response):
        if request.path == "/favicon.ico":
            return response
        elif request.path.startswith("/static"):
            return response

        now = time.time()
        duration = round(now - g.start, 2)
        dt = datetime.datetime.fromtimestamp(now)
        timestamp = rfc3339(dt, utc=True)

        ip = request.headers.get("X-Forwarded-For", request.remote_addr)
        host = request.host.split(":", 1)[0]
        args = dict(request.args)

        log_params = [
            ("method", request.method, "blue"),
            ("path", request.path, "blue"),
            ("status", response.status_code, "yellow"),
            ("duration", duration, "green"),
            ("time", timestamp, "magenta"),
            ("ip", ip, "red"),
            ("host", host, "red"),
            ("params", args, "blue"),
        ]

        if request.json:
            log_params.append(("json", request.json, "white"))

        request_id = request.headers.get("X-Request-ID")
        if request_id:
            log_params.append(("request_id", request_id, "yellow"))

        parts = []
        for name, value, color in log_params:
            part = colors.color("{}={}".format(name, value), fg=color)
            parts.append(part)
        line = " ".join(parts)

        app.logger.info(line)

        return response