lib_autobk.py

#!/usr/local/bin/python3
import logging as mLog
from logging import Formatter, FileHandler
from logging.handlers import RotatingFileHandler
from configparser import RawConfigParser
from subprocess import Popen, PIPE
from datetime import timedelta, datetime, time
import hashlib as mHash

## Exceptions
class AutoBkError(Exception): pass

###############################
# Global Configurations and Constants
oLog		= mLog.getLogger() # root logger
sAt			= 'autobk:%s=%s'
sCombo		= '{} @ {}'
sAuthKey	= '{}:{}'
sSubPath	= "{}/{}"
sSqlTimeFmt	= '%Y-%m-%d %H:%M:%S'

###############################
# Loads the configuration file and logger
def LoadConfig(sMod, *, sIniFile='./autobk.ini', bRotate=False):
	global oLog, sAt
	# Parse Config File
	oINI = RawConfigParser()
	oINI.read([sIniFile])

	# Load Logging config
	sIni = 'Logging'
	sLogFile = oINI.get(sIni, 'File', fallback='./autobk.log')
	iLogSize = oINI.getint(sIni, 'MaxSize', fallback=64000)
	iLogCount = oINI.getint(sIni, 'Count', fallback=3)
	sLogLevel = oINI.get(sIni, 'Level', fallback=mLog.INFO)
	sAt = sMod + ':%s=%s'

	# Logging Components
	oF = Formatter('%(asctime)s - %(message)s', sSqlTimeFmt)
	oH = RotatingFileHandler(sLogFile, 'a', iLogSize, iLogCount) if bRotate else FileHandler(sLogFile)
	oH.setFormatter(oF)

	# Setup Loggers
	oLog.setLevel(mLog.WARNING)
	oLog.addHandler(oH)
	oLog = mLog.getLogger('AutoBk') # Switch to local logger to avoid spam from other modules
	oLog.setLevel(sLogLevel)
	oLog.addHandler(oH)
	oLog.propagate = False

	return (oINI, oLog, sAt)

###############################
# Returns the next iWeekday@iHour from tFrom
def NextWeekday(tFrom, iWeekday, iHour, iWeeks=1):
	if iWeeks <= 0:
		tNextDay = tFrom + timedelta(days=1)
		return tNextDay.replace(hour=iHour, minute=0, second=0, microsecond=0)
	else:
		iOffset = (iWeekday - tFrom.isoweekday()) % 7
		if iOffset > 0:
			iWeeks -= 1
		iOffset += iWeeks * 7
		tNext = tFrom + timedelta(days=iOffset)
		return tNext.replace(hour=iHour, minute=0, second=0, microsecond=0)

###############################
# Executes a script in a new process and waits for completion
def CallScript(sName, sScript, *, lsArg=None, iTimeout=60, bOutIsErr=True):
	# Prepare arguments for process call
	lsParam = ['python3', sScript]
	if (lsArg is not None): lsParam += lsArg

	# Execute script
	oLog.info(sAt, sName, 'calling')
	oProc = Popen(lsParam, stdout=PIPE, text=True)
	sOut = None

	# Wait for completion
	try:
		(sOut, sErr) = oProc.communicate(timeout=iTimeout)
	except Exception as oErr:
		oLog.error(sAt, sName, 'timeout')
		oProc.kill()

	if (oProc.returncode == 0):
		oLog.info(sAt, sName, 'complete')
		return None if (bOutIsErr) else sOut
	else:
		oLog.error(sAt, sName, 'failed')
		return sOut if (bOutIsErr) else None

###############################
# Sends an HTTP request and returns the response
def HttpRequest(oHttpCnx, sURL, dnHdrs, *, bPost=False, bData=True, sMsg=None, sFallbackURL=None):
	# Send HTTP transfer request message to get a file
	oHttpCnx.request('POST' if (bPost) else 'GET', sURL, sMsg, dnHdrs)
	oResponse = oHttpCnx.getresponse()
	if (oResponse.status == 200 or oResponse.status == 302):
		return oResponse.read() if bData else oResponse
	elif (oResponse.status == 404 and sFallbackURL is not None):
		oResponse.read() # Must read all data before trying fallback
		return HttpRequest(oHttpCnx, sFallbackURL, dnHdrs, bPost=bPost, bData=bData, sMsg=sMsg)
	else:
		raise AutoBkError('Bad HTTP Response: {}'.format(oResponse.status))
	
###############################
# Calculate MD5 Hash of a file
def FileHash(sFile):
	oHash = mHash.md5()
	with open(sFile, 'rb') as oF:
		for sData in iter(lambda: oF.read(4096), b''):
			oHash.update(sData)
	return oHash.hexdigest()