A Python logging handler for Fluentd event collector
Project description
WARNING: This is a fork of the https://github.com/fluent/fluent-logger-python project to work with asyncio.
Many web/mobile applications generate huge amount of event logs (c,f. login, logout, purchase, follow, etc). To analyze these event logs could be really valuable for improving the service. However, the challenge is collecting these logs easily and reliably.
Fluentd solves that problem by having: easy installation, small footprint, plugins, reliable buffering, log forwarding, etc.
aiofluent is a Python library, to record the events from Python application.
Requirements
Python 3.5 or greater
msgpack-python
Installation
This library is distributed as ‘aiofluent’ python package. Please execute the following command to install it.
$ pip install aiofluent
Configuration
Fluentd daemon must be launched with a tcp source configuration:
<source> type forward port 24224 </source>
To quickly test your setup, add a matcher that logs to the stdout:
<match app.**> type stdout </match>
Usage
FluentSender Interface
sender.FluentSender is a structured event logger for Fluentd.
By default, the logger assumes fluentd daemon is launched locally. You can also specify remote logger by passing the options.
from aiofluent import sender
# for local fluent
logger = sender.FluentSender('app')
# for remote fluent
logger = sender.FluentSender('app', host='host', port=24224)
For sending event, call emit method with your event. Following example will send the event to fluentd, with tag ‘app.follow’ and the attributes ‘from’ and ‘to’.
# Use current time
logger.emit('follow', {'from': 'userA', 'to': 'userB'})
# Specify optional time
cur_time = int(time.time())
logger.emit_with_time('follow', cur_time, {'from': 'userA', 'to':'userB'})
You can detect an error via return value of emit. If an error happens in emit, emit returns False and get an error object using last_error method.
if not logger.emit('follow', {'from': 'userA', 'to': 'userB'}):
print(logger.last_error)
logger.clear_last_error() # clear stored error after handled errors
If you want to shutdown the client, call close() method.
logger.close()
Event-Based Interface
This API is a wrapper for sender.FluentSender.
First, you need to call sender.setup() to create global sender.FluentSender logger instance. This call needs to be called only once, at the beginning of the application for example.
Initialization code of Event-Based API is below:
from aiofluent import sender
# for local fluent
sender.setup('app')
# for remote fluent
sender.setup('app', host='host', port=24224)
Then, please create the events like this. This will send the event to fluentd, with tag ‘app.follow’ and the attributes ‘from’ and ‘to’.
from aiofluent import event
# send event to fluentd, with 'app.follow' tag
event.Event('follow', {
'from': 'userA',
'to': 'userB'
})
event.Event has one limitation which can’t return success/failure result.
Other methods for Event-Based Interface.
sender.get_global_sender # get instance of global sender
sender.close # Call FluentSender#close
Handler for buffer overflow
You can inject your own custom proc to handle buffer overflow in the event of connection failure. This will mitigate the loss of data instead of simply throwing data away.
import msgpack
from io import BytesIO
def handler(pendings):
unpacker = msgpack.Unpacker(BytesIO(pendings))
for unpacked in unpacker:
print(unpacked)
logger = sender.FluentSender('app', host='host', port=24224, buffer_overflow_handler=handler)
You should handle any exception in handler. aiofluent ignores exceptions from buffer_overflow_handler.
This handler is also called when pending events exist during close().
Python logging.Handler interface
This client-library also has FluentHandler class for Python logging module.
import logging
from aiofluent import handler
custom_format = {
'host': '%(hostname)s',
'where': '%(module)s.%(funcName)s',
'type': '%(levelname)s',
'stack_trace': '%(exc_text)s'
}
logging.basicConfig(level=logging.INFO)
l = logging.getLogger('fluent.test')
h = handler.FluentHandler('app.follow', host='host', port=24224)
formatter = handler.FluentRecordFormatter(custom_format)
h.setFormatter(formatter)
l.addHandler(h)
l.info({
'from': 'userA',
'to': 'userB'
})
l.info('{"from": "userC", "to": "userD"}')
l.info("This log entry will be logged with the additional key: 'message'.")
You can also customize formatter via logging.config.dictConfig
import logging.config
import yaml
with open('logging.yaml') as fd:
conf = yaml.load(fd)
logging.config.dictConfig(conf['logging'])
A sample configuration logging.yaml would be:
logging:
version: 1
formatters:
brief:
format: '%(message)s'
default:
format: '%(asctime)s %(levelname)-8s %(name)-15s %(message)s'
datefmt: '%Y-%m-%d %H:%M:%S'
fluent_fmt:
'()': fluent.handler.FluentRecordFormatter
format:
level: '%(levelname)s'
hostname: '%(hostname)s'
where: '%(module)s.%(funcName)s'
handlers:
console:
class : logging.StreamHandler
level: DEBUG
formatter: default
stream: ext://sys.stdout
fluent:
class: fluent.handler.FluentHandler
host: localhost
port: 24224
tag: test.logging
formatter: fluent_fmt
level: DEBUG
none:
class: logging.NullHandler
loggers:
amqp:
handlers: [none]
propagate: False
conf:
handlers: [none]
propagate: False
'': # root logger
handlers: [console, fluent]
level: DEBUG
propagate: False
License
Apache License, Version 2.0
1.2.9 (2020-10-22)
Only log errors every 30 seconds
1.2.8 (2020-05-15)
Handle TypeError formatting log data
1.2.7 (2020-03-09)
Fix repo location
1.2.6 (2020-01-06)
Improve error logging [vangheem]
1.2.5 (2019-12-19)
Handle event loop closed error [vangheem]
1.2.4 (2019-12-19)
Increase max queue size
1.2.3 (2019-04-01)
Fix release
1.2.2 (2019-04-01)
nanosecond_precision by default [davidonna]
1.2.1 (2018-10-31)
Add support for nanosecond precision timestamps [davidonna]
1.2.0 (2018-06-14)
Maintain one AsyncIO queue for all logs [vangheem]
1.1.4 (2018-05-29)
Handle RuntimeError on canceling tasks/cleanup [vangheem]
1.1.3 (2018-02-15)
Lock calling the close method of sender [vangheem]
Increase default timeout [vangheem]
1.1.2 (2018-02-07)
lock the whole method [vangheem]
1.1.1 (2018-02-07)
Use lock on getting connection object [vangheem]
1.1.0 (2018-01-25)
Move to using asyncio connection infrastructure instead of sockets [vangheem]
1.0.8 (2018-01-04)
Always close out buffer data [vangheem]
1.0.7 (2018-01-04)
Handle errors processing log queue [vangheem]
1.0.6 (2017-11-14)
Prevent log queue from getting too large [vangheem]
1.0.5 (2017-10-17)
Fix release to include CHANGELOG.rst file [vangheem]
1.0.4 (2017-10-10)
Fix pushing initial record
1.0.3 (2017-10-10)
Handle Runtime error when logging done before event loop started [vangheem]
1.0.2 (2017-10-09)
Fix to make normal logging call async [vangheem]
1.0.1 (2017-07-03)
initial release
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