source: tmcsimulator/trunk/src/python/unifiedlogger/cad_watcher.py @ 687

import json, time, ConfigParser, os

from copy import deepcopy



# CAD comment log Watcher

# Look for changes in the CAD comment log.

# The CADserver will append new comments to the log as they arrive 

# from clients.  We only need to keep track of the log length in order to

# determine if a new comment has been added.  We will output the 

# new messages that arrived during the last wait interval. 

# jdalbey  7/6/2019



lastLineNum = 0

configdir = "config"  # default dir for production



def setup(dir):

    global lastLineNum, configdir

    lastLineNum = 0

    configdir = dir

    return



# Retrieve new messages from CAD comment log 

def getLogEntries():

    global lastLineNum, configdir

    # get path to input file from configuration

    config = ConfigParser.ConfigParser()

    config.read(configdir+'/logging_service.cfg')

    logfilepath  = config.get('Paths', 'UnifiedLogPath')

    pathToLog = logfilepath + "CADcomments.log"

    

    try:

        text_file = open(pathToLog, "r")

    except IOError as ex:

        if ex.errno == 2:

            # 'No such file or directory'

            # Assume this is a read sync problem: Don't modify lastLineNum

            print pathToLog + " missing, skipping file read."

            #lastLineNum = 0   #Start over

            return []

        else:

            print "IOError reading "+pathToLog+" file."

            print "errno: ",ex.errno

            

    else:

        # Check file size

        fileSize = os.path.getsize(pathToLog)

        if fileSize == 0:

            print pathToLog+" is empty, skipping file read and resetting."

            lastLineNum = 0   #Start over

            return []

        else: # file is good, read it.

            msgList = text_file.read().strip().split('\n')

            text_file.close()

            currList = []

            currList = msgList[lastLineNum:] # new items since last file read

            lastLineNum = len(msgList)

            return currList



# Local main for unit testing

def main():

    setup("config/devlinux")

    # Loop Forever, checking every five seconds

    while True:

        # Look for new messages

        answer = getLogEntries()

        # Output results

        for item in answer:

            print item

        # wait 

        time.sleep(5)



if __name__ == "__main__":

    main()