plogchain 0.1.0

Python Logging based on blockchain

Plogchain

Python Logging based on blockchain.

Messages get chained

The current log line contains the signature of the previous line with your secret.

• detect lines deletion
• detect logs tampering

Philosophy

The package is intended to be a lightweight util for generating incorruptible logs.

For this pupose we rely as much as possible on standard packages: few dependencies, high quality.

The formatters are easy extensible by simply deriving from Basic.

Usage

Install

pip install plogchain

Choose your log type

Many types of logs are supported out-of-the-box:

• Basic raw text, relying on the standard formatter
• Json structured log lines with static & dynamic fields
• CSV work in progress

You can write a custom formatter in 20-ish lines.

Init once in main

from plogchain import LogChainer

# Initialize a default chainer.
theLogger = LogChainer()

# Register the formatter to the logger.
theLogger.initLogging()

Have a look at the comprehensive guide of constructor parameters.

Use everywhere with python logging module

import logging

logging.debug("My message")
logging.info("Some information")

Check your logs integrity afterwards

from plogchain import LogChainer

aLogChain = [
	"2020-03-30 13:38:00.782|0ec90b9839fdd964|TestChaining.py:20 test_logging_happy_case hello gg",
	"2020-03-30 13:38:00.782|2e3f1b4a7b946fb1|TestChaining.py:21 test_logging_happy_case voila1",
	"2020-03-30 13:38:00.782|10d1ab606618492a|TestChaining.py:22 test_logging_happy_case voila2",
	"2020-03-30 13:38:00.782|805757e144f4e385|TestChaining.py:23 test_logging_happy_case voila5",
	"2020-03-30 13:38:00.782|3bda90b5af77d3fe|TestChaining.py:24 test_logging_happy_case voila4"
]
result = LogChainer.verify(aLogChain)

if not result:
	print("Last good line", result.prevLine)
	print("First bad line", result.line)
else:
	print("All right")

Constructor parameters

They are passed as a dict and/or named arguments.

from plogchain import LogChainer

theLogger = plogchain.LogChainer(verbosity = 3, secret = "mySignatureKey")

params = {"verbosity": 3, "secret": "mySignatureKey"}
theLogger = plogchain.LogChainer(params, timestampFmt = "iso")

Param	Default value	Description
formatterCls	formatters.Basic	Type of logging to perform, raw text, json, custom
format	see below	Placeholder string used by raw-text loggers
secret	secrets.token_urlsafe(128)	Signature key to compute the line signature
seed	secrets.token_urlsafe()	Random string to sign into the first log line
timestampFmt	"iso"	iso for 8601 or strftime compatible placeholders
timestampPrecision	"milliseconds"	timespec element used by the datetime library
timestampUtc	False	Transform the timestamp to its value in UTC
stream	cout	Where the logs are sent, file/console/custom stream
verbosity	0	Number [0..5] mapped to a logging.level

The default format is %(timestamp)s %(levelLetters)s %(fileLine)-15s %(funcName)-15s %(message)-60s |%(signature)s. It relies on some extra fields like the signature at its end.

Plogchain extra logging fields

We enrich the standard logging record with some handy fields:

Name	Description
fileLine	Widespread filename:lineno
levelLetters	4 first letters of logging level names: short and unambiguous
signature	The digital signature of the previous line. Include it in all your lines to benefit from the chaining
timestamp	Improved version of asctime, see below

The timestamp field offers more flexibility than asctime in regards to:

• the precision; can go up to the micro seconds (msecs cannot)
• the decimal separator; you choose, '.' by default
• utc or local timezone
• customize the format only in one place: timestampFmt

Dynamic logging fields (WIP)

The package is suitable for server logging which context changes from one transaction to another. Here is an example of setting contextual information throughout the lifecycle of a server:

	def startServer(containerName)
		# Static formatting at program startup...
		theLogger = LogChainer(formatterCls = formatters.Json)
		theLogger.initLogging()
		theLogger.setField(containerName = containerName)

	def handleTransaction(transactionId, userId):
		# More contextual data later on
		theLogger.setField(uId = userId, trxId = transactionId)

Contributing

Install

Simply clone and submit pull requests.

Testing

The unit tests are located in the test folder which contains the __main__.py entrypoint.

# Run all
python test

# Get additional options
python test --help

Delivery

Use to the awesome Poetry tool for this purpose:

poetry build
poetry publish