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quay/loghandler.py

115 lines
3.7 KiB
Python
Executable File

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import absolute_import
import datetime
import json
import logging
import re
import traceback
LOG_FORMAT_REGEXP = re.compile(r'\((.+?)\)', re.IGNORECASE)
def _json_default(obj):
"""
Coerce everything to strings.
All objects representing time get output as ISO8601.
"""
if isinstance(obj, (datetime.date, datetime.time, datetime.datetime)):
return obj.isoformat()
elif isinstance(obj, Exception):
return "Exception: %s" % str(obj)
return str(obj)
# skip natural LogRecord attributes
# http://docs.python.org/library/logging.html#logrecord-attributes
RESERVED_ATTRS = set([
'args', 'asctime', 'created', 'exc_info', 'exc_text', 'filename', 'funcName', 'levelname',
'levelno', 'lineno', 'module', 'msecs', 'message', 'msg', 'name', 'pathname', 'process',
'processName', 'relativeCreated', 'stack_info', 'thread', 'threadName'
])
class JsonFormatter(logging.Formatter):
"""
A custom formatter to format logging records as json strings.
extra values will be formatted as str() if nor supported by
json default encoder
"""
def __init__(self, *args, **kwargs):
"""
:param json_default: a function for encoding non-standard objects
as outlined in http://docs.python.org/2/library/json.html
:param json_encoder: optional custom encoder
:param json_serializer: a :meth:`json.dumps`-compatible callable
that will be used to serialize the log record.
:param prefix: an optional key prefix to nest logs
"""
self.json_default = kwargs.pop("json_default", _json_default)
self.json_encoder = kwargs.pop("json_encoder", None)
self.json_serializer = kwargs.pop("json_serializer", json.dumps)
self.default_values = kwargs.pop("default_extra", {})
self.prefix_key = kwargs.pop("prefix_key", "data")
logging.Formatter.__init__(self, *args, **kwargs)
self._fmt_parameters = self._parse_format_string()
self._skip_fields = set(self._fmt_parameters)
self._skip_fields.update(RESERVED_ATTRS)
def _parse_format_string(self):
"""Parses format string looking for substitutions"""
standard_formatters = LOG_FORMAT_REGEXP
return standard_formatters.findall(self._fmt)
def add_fields(self, log_record, record, message_dict):
"""
Override this method to implement custom logic for adding fields.
"""
target = log_record
if self.prefix_key:
log_record[self.prefix_key] = {}
target = log_record[self.prefix_key]
for field, value in record.__dict__.iteritems():
if field in self._fmt_parameters and field in RESERVED_ATTRS:
log_record[field] = value
elif field not in RESERVED_ATTRS:
target[field] = value
target.update(message_dict)
target.update(self.default_values)
def format(self, record):
"""Formats a log record and serializes to json"""
message_dict = {}
if isinstance(record.msg, dict):
message_dict = record.msg
record.message = None
if "message" in message_dict:
record.message = message_dict.pop("message", "")
else:
record.message = record.getMessage()
# only format time if needed
if "asctime" in self._fmt_parameters:
record.asctime = self.formatTime(record, self.datefmt)
# Display formatted exception, but allow overriding it in the
# user-supplied dict.
if record.exc_info and not message_dict.get('exc_info'):
message_dict['exc_info'] = traceback.format_list(traceback.extract_tb(record.exc_info[2]))
log_record = {}
self.add_fields(log_record, record, message_dict)
return self.json_serializer(log_record, default=self.json_default, cls=self.json_encoder)