logstash_formatter: JSON logs for logstash

This library is provided to allow standard python logging to output log data as json objects ready to be shipped out to logstash.

Installing

Pip:

pip install logstash_formatter

Pypi:

https://pypi.python.org/pypi/logstash_formatter

Manual:

python setup.py install

Usage

Json outputs are provided by the LogstashFormatter logging formatter.

import logging
from logstash_formatter import LogstashFormatter

logger = logging.getLogger()
handler = logging.StreamHandler()
formatter = LogstashFormatter()

handler.setFormatter(formatter)
logger.addHandler(handler)

The LogstashFormatter may take the following named parameters:

• fmt: Config as a JSON string that supports: * extra: provide extra fields always present in logs * source_host: override source host name
• json_cls: JSON encoder to forward to json.dump

• json_default: Default JSON representation for unknown types,

  by default coerce everythiung to a string

You can also add extra fields to your json output by specifying a dict in place of message, or by specifying the named argument extra as a dictionary. When supplying the exc_info named argument with a truthy value, and if an exception is found on the stack, its traceback will be attached to the payload as well.

logger.info({"account": 123, "ip": "172.20.19.18"})
logger.info("classic message for account: %s", account, extra={"account": account})

try:
  h = {}
  h['key']
except:
  logger.info("something unexpected happened", exc_info=True)

Sample output

The following keys will be found in the output JSON:

• @source_host: source hostname for the log
• @timestamp: ISO 8601 timestamp
• @message: short message for this log
• @fields: all extra fields

{
  "@fields": {
      "account": "pyr",
      "args": [],
      "created": 1367480388.013037,
      "exception": [
          "Traceback (most recent call last):\n",
          "  File \"toto.py\", line 16, in <module>\n    k['unknown']\n",
          "KeyError: 'unknown'\n"
      ],
      "filename": "toto.py",
      "funcName": "<module>",
      "levelname": "WARNING",
      "levelno": 30,
      "lineno": 18,
      "module": "toto",
      "msecs": 13.036966323852539,
      "name": "root",
      "pathname": "toto.py",
      "process": 1819,
      "processName": "MainProcess",
      "relativeCreated": 18.002986907958984,
      "thread": 140060726359808,
      "threadName": "MainThread"
  },
  "@message": "TOTO",
  "@source_host": "phoenix.spootnik.org",
  "@timestamp": "2013-05-02T09:39:48.013158"
}