From 6e6b43eb795652f8c0f489ac3e2abef6364481cf Mon Sep 17 00:00:00 2001
From: Vangelis Banos <vangelis@archive.org>
Date: Wed, 20 Mar 2019 11:53:32 +0000
Subject: [PATCH] Add option to load logging conf from JSON file

New option `--logging-conf-file` to load `logging` conf from a JSON
file.

Prefer JSON over the `configparser` format supported by
`logging.config.fileConfig` because JSON format is much better (nesting
is supported) and its easier to detect errors.
---
 warcprox/main.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/warcprox/main.py b/warcprox/main.py
index 7fe5011..98867b6 100644
--- a/warcprox/main.py
+++ b/warcprox/main.py
@@ -29,7 +29,9 @@ try:
 except ImportError:
     import Queue as queue
 
+import json
 import logging
+import logging.config
 import sys
 import hashlib
 import argparse
@@ -239,6 +241,9 @@ def _build_arg_parser(prog='warcprox', show_hidden=False):
     arg_parser.add_argument(
             '--trace', dest='trace', action='store_true',
             help='very verbose logging')
+    arg_parser.add_argument(
+            '--logging-conf-file', dest='logging_conf_file', default=None,
+            help=('reads logging configuration from a JSON file'))
     arg_parser.add_argument(
             '--version', action='version',
             version="warcprox {}".format(warcprox.__version__))
@@ -302,6 +307,11 @@ def main(argv=None):
                 '%(asctime)s %(process)d %(levelname)s %(threadName)s '
                 '%(name)s.%(funcName)s(%(filename)s:%(lineno)d) %(message)s'))
 
+    if args.logging_conf_file:
+        with open(args.logging_conf_file, 'r') as fd:
+            conf = json.load(fd)
+            logging.config.dictConfig(conf)
+
     # see https://github.com/pyca/cryptography/issues/2911
     cryptography.hazmat.backends.openssl.backend.activate_builtin_random()