lcmlog-server/lcmlog-server

#!/usr/bin/env python3

DIR="/usr/local/src/lcm-unimi/lcmlog"

import os
import sys
import pwd
import logging
import logging.handlers

def main():

	# Preparing the logger
	logger = logging.getLogger(__name__)
	file_formatter = logging.Formatter("%(asctime)s | %(levelname)8s | %(message)s")
	logger.setLevel(logging.INFO)

	# Logger handle to log all info
	file_handler = logging.handlers.TimedRotatingFileHandler(filename = DIR + "/logs/logfile", when = "W6", backupCount = 10)
	file_handler.setFormatter(file_formatter)

	logger.addHandler(file_handler)

	user_id = os.geteuid()
	user_name = pwd.getpwuid(user_id).pw_name

	logger.info("Started by user " + user_name + " (id " + str(user_id) + ")")

	try:
		method = input() # Can be GET or POST
		logger.info("Method: " + method)
		kind = input()   # Can be 150 or Admin
		logger.info("Kind: " + kind)
		date = input()
		logger.info("Date: " + date)

		if kind != "150" and kind != "Admin":
			raise KindError
		if method == "POST":
			auth(user_id, "POST", kind)
			tags = input()
			logger.info("Tags: " + tags)
			log = sys.stdin.read() # Read the log content
			post(user_name, kind, date, tags, log)
		elif method == "GET":
			auth(user_id, "GET", kind)
			get(kind, date)
		else:
			raise MethodError

	except EOFError as error:
		logger.critical("1 Not enough input lines")
		sys.exit(1)
	except FileNotFoundError as error:
		logger.critical("2 File not found")
		sys.exit(2)
	except FileExistsError as error:
		logger.critical("3 File already exists")
		sys.exit(3)
	except OSError as error:
		logger.critical("4 File error")
		sys.exit(4)
	except MethodError as error:
		logger.critical("5 Undefined method")
		sys.exit(5)
	except KindError as error:
		logger.critical("6 Undefined log kind")
		sys.exit(6)
	except AuthError as error:
		logger.critical("7 Authentication error")
		sys.exit(7)
	except Exception as error:
		logger.critical("8 Generic error: " + str(error))
		sys.exit(8)

	finally:
		logger.info("End\n")

# Print specified log on stdout
def get(kind, date):
	with open(DIR + "/data/" + kind + "/" + date, "r") as f:
		sys.stdout.write("User: " + f.readline())
		sys.stdout.write("Tags: " + f.readline())
		sys.stdout.write("\n" + f.read())

# Write log
def post(user_name, kind, date, tags, log):
	with open(DIR + "/data/" + kind + "/" + date, "x") as f:
		f.write(user_name + "\n" + tags + "\n" + log)

# Checks if the user has the permissions to use the requested method
def auth(user_id, method, kind):
	with open(DIR + "/auth/" + kind + "/" + method) as f:
		for line in f:
			if int(line) == user_id:
				return
	raise AuthError()

# Error definitions
class AuthError(Exception):
	pass
class KindError(Exception):
	pass
class MethodError(Exception):
	pass

# Starting point
if __name__ == "__main__":
	main()