Captains log, stardate...

Nice! logging is done. I'll get csv-logfiles on every clean cycle. 

poseLogFilename = 'poseDummy'
poseLogFile = open(poseLogFilename + ".csv", 'w')
poseLogWriter = csv.writer(poseLogFile)
rawLogFilename = 'rawDummy'
rawLogFile = open(rawLogFilename + ".csv", 'w')
rawLogWriter = csv.writer(rawLogFile)

#MQTT callback functions
def on_message(client, userdata, message):
    data = message.payload
    global poseLogFilename
    global poseLogFile
    global poseLogWriter
    global rawLogFilename
    global rawLogFile
    global rawLogWriter

    if message.topic == MQTT_Config.HA_name + "/button/" + DeviceName + "_" + DeviceID + "/set":
        command=data.decode("utf-8")
        # start logging
        if  command == "Clean":
            # open logfile
            print("Started cleaning cycle")
            poseLogFile.close()
            poseLogFilename = "./Roomba/Logs/" + datetime.datetime.now().isoformat('_', 'seconds') + "_pose"
            poseLogFile = open(poseLogFilename + ".csv", 'w')
            poseLogWriter = csv.writer(poseLogFile)
            rawLogFile.close()
            rawLogFilename = "./Roomba/Logs/" + datetime.datetime.now().isoformat('_', 'seconds')+ "_raw"
            rawLogFile = open(rawLogFilename + ".csv", 'w')
            rawLogWriter = csv.writer(rawLogFile)
    if message.topic == MQTT_Config.HA_name + "/device_automation/" + DeviceName + "_" + DeviceID + "/event_DoneCleaning":
        event=data.decode("utf-8")
        # start logging
        if event == "done cleaning":
            # close log
            print("Cleaning cycle is done. Save logfile and start postprocess")
            poseLogFile.close()
            poseLogFile = open('poseDummy.csv', 'w')
            poseLogWriter = csv.writer(poseLogFile)
            rawLogFile.close()
            rawLogFile = open('rawDummy.csv', 'w')
            rawLogWriter = csv.writer(rawLogFile)
            # plot image from CSV file.

    if message.topic == MQTT_Config.HA_name + "/device/roomba/raw":
        rawJson=json.loads(data.decode("utf-8"))
        # start logging
        #print(rawJson['mEL'])            
        #print(rawJson['mER'])            
        #print(rawJson['rTh'])            
        #print(rawJson['Xacc'])            
        #print(rawJson['Yacc'])            
        #print(rawJson['Yaw'])
        if not rawLogFile.closed:
            rawLogData = [rawJson['mEL'],rawJson['mER'],rawJson['rTh'],rawJson['Xacc'],rawJson['Yacc'],rawJson['Yaw']]
            rawLogWriter.writerow(rawLogData)
        else:
            print("Raw logfile was closed")
    if message.topic == MQTT_Config.HA_name + "/device/roomba/pose":
        poseJson=json.loads(data.decode("utf-8"))
        # start logging
        #print(poseJson['X'])            
        #print(poseJson['Y'])
        #print(poseJson['rTh']) 
        if not poseLogFile.closed:
            poseLogData = [poseJson['X'],poseJson['Y'],poseJson['rTh']]
            poseLogWriter.writerow(poseLogData)
        else:
            print("Pose logfile was closed")

Only thing left now is to plot the pose-log to an image-file and post that with MQTT....

Anyone who knows how??