@@ -38,6 +38,8 @@

 #     status page and parsed the signal data from the html.

 #   * v23 released 11 Jun 2021 by J L Owrey; remove unused code.

 #   * v24 released 14 Jun 2021 by J L Owrey; minor revisions

+#   * v25 released 9 Jul 2021 by J L Owrey; improved handling of

+#         node status function

 #

 #2345678901234567890123456789012345678901234567890123456789012345678901234567890

@@ -59,7 +61,8 @@ _SERVER_MODE = "primary"

 # set url of the aredn node

-_DEFAULT_AREDN_NODE_URL = "{your AREDN mesh node url"

+_DEFAULT_AREDN_NODE_URL = \

+    "{your node url}"

     ### FILE AND FOLDER LOCATIONS ###

@@ -101,7 +104,7 @@ debugMode = False

 # count of failed attempts to get data from aredn node

 failedUpdateCount = 0

 # detected status of aredn node device

-nodeOnline = True

+nodeOnline = False

 # ip address of aredn node

 arednNodeUrl = _DEFAULT_AREDN_NODE_URL

@@ -165,10 +168,8 @@ def terminateAgentProcess(signal, frame):

            signal, frame - dummy parameters

        Returns: nothing

     """

-    # Inform downstream clients by removing output data file.

-    if os.path.exists(_OUTPUT_DATA_FILE):

-       os.remove(_OUTPUT_DATA_FILE)

     print('%s terminating arednsig agent process' % getTimeStamp())

+    setStatusToOffline()

     sys.exit(0)

 ##end def

@@ -183,12 +184,8 @@ def getNodeData(dData):

     """

     try:

         currentTime = time.time()

-

         response = urlopen(arednNodeUrl, timeout=_HTTP_REQUEST_TIMEOUT)

-

-        if verboseMode:

-            requestTime = time.time() - currentTime

-            print("http request: %.4f seconds" % requestTime)

+        requestTime = time.time() - currentTime

         content = response.read().decode('utf-8')

         content = content.replace('\n', '')

@@ -206,9 +203,10 @@ def getNodeData(dData):

     if debugMode:

         print(content)

+    if verboseMode:

+        print("http request successful: %.4f sec" % requestTime)

     dData['content'] = content

-

     return True

 ##end def

@@ -237,14 +235,19 @@ def parseDataString(dData):

         snr = snr.replace(' ','')

         lsnr = snr.split('/')

-        dData['time'] = getEpochSeconds(getTimeStamp())

         dData['signal'] = lsnr[0]

         dData['noise'] = lsnr[1]

         dData['snr'] = lsnr[2]

-    

     except Exception as exError:

         print("%s parse failed: %s" % (getTimeStamp(), exError))

         return False

+    ## end try

+

+    # Add status information to dictionary object.

+    dData['date'] = getTimeStamp()

+    dData['chartUpdateInterval'] = chartUpdateInterval

+    dData['dataRequestInterval'] = dataRequestInterval

+    dData['serverMode'] = _SERVER_MODE

     return True

 ##end def

@@ -262,16 +265,12 @@ def writeOutputFile(dData):

     # data items are sent to the client file.

     #    * The last database update date and time

     #    * The data request interval

-    lastUpdate = time.strftime( "%m.%d.%Y %T", 

-                                time.localtime(dData['time']) )

     # Format data into a JSON string.

     jsData = json.loads("{}")

     try:

-        jsData.update({"date": lastUpdate})

-        jsData.update({"chartUpdateInterval": chartUpdateInterval})

-        jsData.update({"dataRequestInterval": dataRequestInterval})

-        jsData.update({"serverMode": _SERVER_MODE})

+        for key in dData:

+            jsData.update({key:dData[key]})

         sData = "[%s]" % json.dumps(jsData)

     except Exception as exError:

         print("%s writeOutputFile: %s" % (getTimeStamp(), exError))

@@ -291,6 +290,35 @@ def writeOutputFile(dData):

     return True

 ## end def

+def setNodeStatus(updateSuccess):

+    """Detect if aredn node is offline or not available on

+       the network. After a set number of attempts to get data

+       from the node set a flag that the node is offline.

+       Parameters:

+           updateSuccess - a boolean that is True if data request

+                           successful, False otherwise

+       Returns: nothing

+    """

+    global failedUpdateCount, nodeOnline

+

+    if updateSuccess:

+        failedUpdateCount = 0

+        # Set status and send a message to the log if the device

+        # previously offline and is now online.

+        if not nodeOnline:

+            print('%s node online' % getTimeStamp())

+            nodeOnline = True

+        return

+    elif failedUpdateCount == _MAX_FAILED_DATA_REQUESTS - 1:

+        # Max number of failed data requests, so set

+        # device status to offline.

+        setStatusToOffline()

+    ## end if

+    failedUpdateCount += 1

+##end def

+

+    ### DATABASE FUNCTIONS ###

+

 def updateDatabase(dData):

     """

     Update the rrdtool database by executing an rrdtool system command.

@@ -300,9 +328,12 @@ def updateDatabase(dData):

                         written to the rr database file

     Returns: True if successful, False otherwise

     """

+    

+    time = getEpochSeconds(dData['date'])

+

     # Format the rrdtool update command.

     strFmt = "rrdtool update %s %s:%s:%s:%s:%s:%s:%s:%s"

-    strCmd = strFmt % (_RRD_FILE, dData['time'], dData['signal'], \

+    strCmd = strFmt % (_RRD_FILE, time, dData['signal'], \

              dData['noise'], dData['snr'], '0', \

              '0', '0', '0')

@@ -319,40 +350,11 @@ def updateDatabase(dData):

         return False

     if verboseMode and not debugMode:

-        print("database updated")

+        print("database update successful")

     return True

 ##end def

-def setNodeStatus(updateSuccess):

-    """Detect if aredn node is offline or not available on

-       the network. After a set number of attempts to get data

-       from the node set a flag that the node is offline.

-       Parameters:

-           updateSuccess - a boolean that is True if data request

-                           successful, False otherwise

-       Returns: nothing

-    """

-    global failedUpdateCount, nodeOnline

-

-    if updateSuccess:

-        failedUpdateCount = 0

-        # Set status and send a message to the log if the node was

-        # previously offline and is now online.

-        if not nodeOnline:

-            print('%s aredn node online' % getTimeStamp())

-            nodeOnline = True

-    else:

-        # The last attempt failed, so update the failed attempts

-        # count.

-        failedUpdateCount += 1

-

-    if failedUpdateCount > _MAX_FAILED_DATA_REQUESTS:

-        # Max number of failed data requests, so set

-        # node status to offline.

-        setStatusToOffline()

-##end def

-

 def createGraph(fileName, dataItem, gLabel, gTitle, gStart,

                 lower, upper, addTrend, autoScale):

     """Uses rrdtool to create a graph of specified node data item.

@@ -513,6 +515,7 @@ def main():

     signal.signal(signal.SIGTERM, terminateAgentProcess)

     signal.signal(signal.SIGINT, terminateAgentProcess)

+    print('===================')

     print('%s starting up arednsig agent process' % \

                   (getTimeStamp()))

@@ -568,7 +571,7 @@ def main():

         if currentTime - lastChartUpdateTime > chartUpdateInterval:

             lastChartUpdateTime = currentTime

             p = multiprocessing.Process(target=generateGraphs, args=())

-            p.start()

+            #p.start()

         # Relinquish processing back to the operating system until

         # the next update interval.

@@ -576,9 +579,9 @@ def main():

         elapsedTime = time.time() - currentTime

         if verboseMode:

             if result:

-                print("update successful: %s sec" % elapsedTime)

+                print("update successful: %s sec\n" % elapsedTime)

             else:

-                print("update failed: %s sec" % elapsedTime)

+                print("update failed: %s sec\n" % elapsedTime)

         remainingTime = dataRequestInterval - elapsedTime

         if remainingTime > 0.0:

             time.sleep(remainingTime)

@@ -59,7 +59,7 @@ _SERVER_MODE = "primary"

 # set url of the aredn node

-_DEFAULT_AREDN_NODE_URL = "http://localnode.local.mesh/cgi-bin/status"

+_DEFAULT_AREDN_NODE_URL = "{your AREDN mesh node url"

     ### FILE AND FOLDER LOCATIONS ###

@@ -92,8 +92,8 @@ _CHART_HEIGHT = 150

    ### GLOBAL VARIABLES ###

 # turn on or off of verbose debugging information

-debugOption = False

-verboseDebug = False

+verboseMode = False

+debugMode = False

 # The following two items are used for detecting system faults

 # and aredn node online or offline status.

@@ -174,19 +174,19 @@ def terminateAgentProcess(signal, frame):

   ###  PUBLIC METHODS  ###

-def getNodeData():

+def getNodeData(dData):

     """Send http request to aredn node.  The response from the

        node contains the node signal data as unformatted ascii text.

        Parameters: none

-       Returns: a string containing the node signal data if successful,

-                or None if not successful

+       Returns: True if successful,

+                or False if not successful

     """

     try:

         currentTime = time.time()

         response = urlopen(arednNodeUrl, timeout=_HTTP_REQUEST_TIMEOUT)

-        if debugOption:

+        if verboseMode:

             requestTime = time.time() - currentTime

             print("http request: %.4f seconds" % requestTime)

@@ -201,16 +201,18 @@ def getNodeData():

         # the device is down or unavailable over the network.  In

         # that case return None to the calling function.

         print("%s getNodeData: %s" % (getTimeStamp(), exError))

-        return None

+        return False

     ##end try

-    if verboseDebug:

+    if debugMode:

         print(content)

-   

-    return content

+

+    dData['content'] = content

+

+    return True

 ##end def

-def parseDataString(sData, dData):

+def parseDataString(dData):

     """Parse the node signal data JSON string from the aredn node

        into its component parts.  

        Parameters:

@@ -218,7 +220,7 @@ def parseDataString(sData, dData):

            dData - a dictionary object to contain the parsed data items

        Returns: True if successful, False otherwise

     """

- 

+    sData = dData.pop('content')

     try:

         strBeginSearch = '<nobr>Signal/Noise/Ratio</nobr></th>' \

                          '<td valign=middle><nobr><big><b>'

@@ -247,39 +249,6 @@ def parseDataString(sData, dData):

     return True

 ##end def

-def updateDatabase(dData):

-    """

-    Update the rrdtool database by executing an rrdtool system command.

-    Format the command using the data extracted from the aredn node

-    response.   

-    Parameters: dData - dictionary object containing data items to be

-                        written to the rr database file

-    Returns: True if successful, False otherwise

-    """

-    # Format the rrdtool update command.

-    strFmt = "rrdtool update %s %s:%s:%s:%s:%s:%s:%s:%s"

-    strCmd = strFmt % (_RRD_FILE, dData['time'], dData['signal'], \

-             dData['noise'], dData['snr'], '0', \

-             '0', '0', '0')

-

-    if verboseDebug:

-        print("%s" % strCmd) # DEBUG

-

-    # Run the command as a subprocess.

-    try:

-        subprocess.check_output(strCmd, shell=True,  \

-                             stderr=subprocess.STDOUT)

-    except subprocess.CalledProcessError as exError:

-        print("%s: rrdtool update failed: %s" % \

-                    (getTimeStamp(), exError.output))

-        return False

-

-    if debugOption and not verboseDebug:

-        print("database updated")

-

-    return True

-##end def

-

 def writeOutputFile(dData):

     """Write node data items to the output data file, formatted as 

        a Javascript file.  This file may then be accessed and used by

@@ -297,8 +266,8 @@ def writeOutputFile(dData):

                                 time.localtime(dData['time']) )

     # Format data into a JSON string.

+    jsData = json.loads("{}")

     try:

-        jsData = json.loads("{}")

         jsData.update({"date": lastUpdate})

         jsData.update({"chartUpdateInterval": chartUpdateInterval})

         jsData.update({"dataRequestInterval": dataRequestInterval})

@@ -308,7 +277,7 @@ def writeOutputFile(dData):

         print("%s writeOutputFile: %s" % (getTimeStamp(), exError))

         return False

-    if verboseDebug:

+    if debugMode:

         print(sData)

     try:

@@ -322,6 +291,39 @@ def writeOutputFile(dData):

     return True

 ## end def

+def updateDatabase(dData):

+    """

+    Update the rrdtool database by executing an rrdtool system command.

+    Format the command using the data extracted from the aredn node

+    response.   

+    Parameters: dData - dictionary object containing data items to be

+                        written to the rr database file

+    Returns: True if successful, False otherwise

+    """

+    # Format the rrdtool update command.

+    strFmt = "rrdtool update %s %s:%s:%s:%s:%s:%s:%s:%s"

+    strCmd = strFmt % (_RRD_FILE, dData['time'], dData['signal'], \

+             dData['noise'], dData['snr'], '0', \

+             '0', '0', '0')

+

+    if debugMode:

+        print("%s" % strCmd) # DEBUG

+

+    # Run the command as a subprocess.

+    try:

+        subprocess.check_output(strCmd, shell=True,  \

+                             stderr=subprocess.STDOUT)

+    except subprocess.CalledProcessError as exError:

+        print("%s: rrdtool update failed: %s" % \

+                    (getTimeStamp(), exError.output))

+        return False

+

+    if verboseMode and not debugMode:

+        print("database updated")

+

+    return True

+##end def

+

 def setNodeStatus(updateSuccess):

     """Detect if aredn node is offline or not available on

        the network. After a set number of attempts to get data

@@ -404,7 +406,7 @@ def createGraph(fileName, dataItem, gLabel, gTitle, gStart,

         strCmd += "CDEF:smoothed=dSeries,%s,TREND LINE2:smoothed#006600 " \

                   % trendWindow[gStart]

-    if verboseDebug:

+    if debugMode:

         print("%s" % strCmd) # DEBUG

     # Run the formatted rrdtool command as a subprocess.

@@ -416,7 +418,7 @@ def createGraph(fileName, dataItem, gLabel, gTitle, gStart,

         print("rrdtool graph failed: %s" % (exError.output))

         return False

-    if debugOption:

+    if verboseMode:

         print("rrdtool graph: %s\n" % result.decode('utf-8'), end='')

     return True

@@ -458,7 +460,7 @@ def generateGraphs():

     createGraph('12m_snr', 'SNR', 'dB', 

                 'SNR\ -\ Past\ Year', 'end-12months', 0, 0, 2, autoScale)

-    if debugOption:

+    if verboseMode:

         #print() # print a blank line to improve readability when in debug mode

         pass

 ##end def

@@ -471,16 +473,16 @@ def getCLarguments():

           -u sets the url of the aredn nodeing device

        Returns: nothing

     """

-    global debugOption, verboseDebug, dataRequestInterval, \

+    global verboseMode, debugMode, dataRequestInterval, \

            arednNodeUrl

     index = 1

     while index < len(sys.argv):

-        if sys.argv[index] == '-d':

-            debugOption = True

-        elif sys.argv[index] == '-v':

-            debugOption = True

-            verboseDebug = True

+        if sys.argv[index] == '-v':

+            verboseMode = True

+        elif sys.argv[index] == '-d':

+            verboseMode = True

+            debugMode = True

         elif sys.argv[index] == '-p':

             try:

                 dataRequestInterval = abs(int(sys.argv[index + 1]))

@@ -541,18 +543,13 @@ def main():

         if currentTime - lastDataRequestTime > dataRequestInterval:

             lastDataRequestTime = currentTime

             dData = {}

-            result = True

             # Get the data string from the device.

-            sData = getNodeData()

+            result = getNodeData(dData)

-            # If the first http request fails, try one more time.

-            if sData == None:

-                result = False

-            

             # If successful parse the data.

             if result:

-                result = parseDataString(sData, dData)

+                result = parseDataString(dData)

             # If parse successful, write data output data file.

             if result:

@@ -577,12 +574,11 @@ def main():

         # the next update interval.

         elapsedTime = time.time() - currentTime

-        if debugOption:

+        if verboseMode:

             if result:

-                print("%s update successful:" % getTimeStamp(), end='')

+                print("update successful: %s sec" % elapsedTime)

             else:

-                print("%s update failed:" % getTimeStamp(), end='')

-            print(" %6f seconds\n" % elapsedTime)

+                print("update failed: %s sec" % elapsedTime)

         remainingTime = dataRequestInterval - elapsedTime

         if remainingTime > 0.0:

             time.sleep(remainingTime)

@@ -1,4 +1,4 @@

-#!/usr/bin/python2 -u

+#!/usr/bin/python3 -u

 # The -u option above turns off block buffering of python output. This 

 # assures that each error message gets individually printed to the log file.

 #

@@ -36,24 +36,30 @@

 #   * v22 released 31 Mar 2020 by J L Owrey; upgraded for compatibility with

 #     Aredn firmware version 3.20.3.0.  This agent now downloads the node's

 #     status page and parsed the signal data from the html.

+#   * v23 released 11 Jun 2021 by J L Owrey; remove unused code.

+#   * v24 released 14 Jun 2021 by J L Owrey; minor revisions

 #

 #2345678901234567890123456789012345678901234567890123456789012345678901234567890

 import os

-import urllib2

 import sys

 import signal

 import subprocess

 import multiprocessing

 import time

+import json

+from urllib.request import urlopen

+

+   ### ENVIRONMENT ###

 _USER = os.environ['USER']

+_SERVER_MODE = "primary"

    ### DEFAULT AREDN NODE URL ###

 # set url of the aredn node

-_DEFAULT_AREDN_NODE_URL = "http://localnode:8080/cgi-bin/status"

+_DEFAULT_AREDN_NODE_URL = "http://localnode.local.mesh/cgi-bin/status"

     ### FILE AND FOLDER LOCATIONS ###

@@ -62,30 +68,26 @@ _DOCROOT_PATH = "/home/%s/public_html/arednsig/" % _USER

 # folder for charts and output data file

 _CHARTS_DIRECTORY = _DOCROOT_PATH + "dynamic/"

 # location of data output file

-_OUTPUT_DATA_FILE = _DOCROOT_PATH + "dynamic/arednsigOutputData.js"

-# dummy output data file

-_DUMMY_OUTPUT_FILE = _DOCROOT_PATH + "dynamic/nodeOnline.js"

+_OUTPUT_DATA_FILE = _DOCROOT_PATH + "dynamic/arednsigData.js"

 # database that stores node data

 _RRD_FILE = "/home/%s/database/arednsigData.rrd" % _USER

     ### GLOBAL CONSTANTS ###

+# max number of failed data requests allowed

+_MAX_FAILED_DATA_REQUESTS = 2

 # AREDN node data request interval in seconds

 _DEFAULT_DATA_REQUEST_INTERVAL = 60

+# number seconds to wait for a response to HTTP request

+_HTTP_REQUEST_TIMEOUT = 5

+

 # chart update interval in seconds

 _CHART_UPDATE_INTERVAL = 600

-

-# number seconds to wait for a response to HTTP request

-_HTTP_REQUEST_TIMEOUT = 10

-# max number of failed data requests allowed

-_MAX_FAILED_DATA_REQUESTS = 0

 # standard chart width in pixels

 _CHART_WIDTH = 600

 # standard chart height in pixels

 _CHART_HEIGHT = 150

 # Set this to True only if this server is intended to relay raw

-# node data to a mirror server.

-_RELAY_SERVER = False

    ### GLOBAL VARIABLES ###

@@ -107,8 +109,6 @@ arednNodeUrl = _DEFAULT_AREDN_NODE_URL

 dataRequestInterval = _DEFAULT_DATA_REQUEST_INTERVAL

 # chart update interval

 chartUpdateInterval = _CHART_UPDATE_INTERVAL

-# last node request time

-lastDataPointTime = -1

   ###  PRIVATE METHODS  ###

@@ -122,7 +122,7 @@ def getTimeStamp():

 ##end def

 def getEpochSeconds(sTime):

-    """Convert the time stamp supplied in the weather data string

+    """Convert the time stamp supplied in the supplied string

        to seconds since 1/1/1970 00:00:00.

        Parameters: 

            sTime - the time stamp to be converted must be formatted

@@ -131,8 +131,8 @@ def getEpochSeconds(sTime):

     """

     try:

         t_sTime = time.strptime(sTime, '%m/%d/%Y %H:%M:%S')

-    except Exception, exError:

-        print '%s getEpochSeconds: %s' % (getTimeStamp(), exError)

+    except Exception as exError:

+        print('%s getEpochSeconds: %s' % (getTimeStamp(), exError))

         return None

     tSeconds = int(time.mktime(t_sTime))

     return tSeconds

@@ -150,12 +150,10 @@ def setStatusToOffline():

     # Inform downstream clients by removing output data file.

     if os.path.exists(_OUTPUT_DATA_FILE):

        os.remove(_OUTPUT_DATA_FILE)

-    if os.path.exists(_DUMMY_OUTPUT_FILE):

-       os.remove(_DUMMY_OUTPUT_FILE)

     # If the aredn node was previously online, then send

     # a message that we are now offline.

     if nodeOnline:

-        print '%s aredn node offline' % getTimeStamp()

+        print('%s aredn node offline' % getTimeStamp())

     nodeOnline = False

 ##end def

@@ -170,16 +168,13 @@ def terminateAgentProcess(signal, frame):

     # Inform downstream clients by removing output data file.

     if os.path.exists(_OUTPUT_DATA_FILE):

        os.remove(_OUTPUT_DATA_FILE)

-    if os.path.exists(_DUMMY_OUTPUT_FILE):

-       os.remove(_DUMMY_OUTPUT_FILE)

-    print '%s terminating arednsig agent process' % \

-              (getTimeStamp())

+    print('%s terminating arednsig agent process' % getTimeStamp())

     sys.exit(0)

 ##end def

   ###  PUBLIC METHODS  ###

-def getArednNodeData():

+def getNodeData():

     """Send http request to aredn node.  The response from the

        node contains the node signal data as unformatted ascii text.

        Parameters: none

@@ -187,44 +182,51 @@ def getArednNodeData():

                 or None if not successful

     """

     try:

-        conn = urllib2.urlopen(arednNodeUrl, timeout=_HTTP_REQUEST_TIMEOUT)

+        currentTime = time.time()

-        # Format received data into a single string.

-        content = ""

-        for line in conn:

-            content += line.strip()

-        del conn

+        response = urlopen(arednNodeUrl, timeout=_HTTP_REQUEST_TIMEOUT)

-    except Exception, exError:

+        if debugOption:

+            requestTime = time.time() - currentTime

+            print("http request: %.4f seconds" % requestTime)

+

+        content = response.read().decode('utf-8')

+        content = content.replace('\n', '')

+        content = content.replace('\r', '')

+        if content == "":

+            raise Exception("empty response")

+        

+    except Exception as exError:

         # If no response is received from the device, then assume that

         # the device is down or unavailable over the network.  In

         # that case return None to the calling function.

-        print "%s http error: %s" % (getTimeStamp(), exError)

+        print("%s getNodeData: %s" % (getTimeStamp(), exError))

         return None

+    ##end try

     if verboseDebug:

-        print "http request successful: %d bytes" % len(content)

-

+        print(content)

+   

     return content

 ##end def

-def parseNodeData(sData, dData):

-    """Parse the node  signal data JSON string from the aredn node

+def parseDataString(sData, dData):

+    """Parse the node signal data JSON string from the aredn node

        into its component parts.  

        Parameters:

            sData - the string containing the data to be parsed

            dData - a dictionary object to contain the parsed data items

        Returns: True if successful, False otherwise

     """

-    

-

+ 

     try:

         strBeginSearch = '<nobr>Signal/Noise/Ratio</nobr></th>' \

                          '<td valign=middle><nobr><big><b>'

-        strEndSearch = 'dB'

+        strEndSearch = 'dB</b>'

         iBeginIndex = sData.find(strBeginSearch) + len(strBeginSearch)

         iEndIndex = sData.find(strEndSearch, iBeginIndex)

+        #print("search params: %d, %d" % (iBeginIndex, iEndIndex))

         if iBeginIndex == -1 or iEndIndex == -1:

             raise Exception("signal data not found in status page")

@@ -234,17 +236,14 @@ def parseNodeData(sData, dData):

         lsnr = snr.split('/')

         dData['time'] = getEpochSeconds(getTimeStamp())

-

         dData['signal'] = lsnr[0]

         dData['noise'] = lsnr[1]

         dData['snr'] = lsnr[2]

-    except Exception, exError:

-        print "%s parse failed: %s" % (getTimeStamp(), exError)

+    except Exception as exError:

+        print("%s parse failed: %s" % (getTimeStamp(), exError))

         return False

-    if verboseDebug:

-        print "parse successful"

     return True

 ##end def

@@ -264,21 +263,24 @@ def updateDatabase(dData):

              '0', '0', '0')

     if verboseDebug:

-        print "%s" % strCmd # DEBUG

+        print("%s" % strCmd) # DEBUG

     # Run the command as a subprocess.

     try:

         subprocess.check_output(strCmd, shell=True,  \

                              stderr=subprocess.STDOUT)

-    except subprocess.CalledProcessError, exError:

-        print "%s: rrdtool update failed: %s" % \

-                    (getTimeStamp(), exError.output)

+    except subprocess.CalledProcessError as exError:

+        print("%s: rrdtool update failed: %s" % \

+                    (getTimeStamp(), exError.output))

         return False

+    if debugOption and not verboseDebug:

+        print("database updated")

+

     return True

 ##end def

-def writeOutputDataFile(sData, dData):

+def writeOutputFile(dData):

     """Write node data items to the output data file, formatted as 

        a Javascript file.  This file may then be accessed and used by

        by downstream clients, for instance, in HTML documents.

@@ -293,28 +295,29 @@ def writeOutputDataFile(sData, dData):

     #    * The data request interval

     lastUpdate = time.strftime( "%m.%d.%Y %T", 

                                 time.localtime(dData['time']) )

-    sDate = "[{\"date\":\"%s\",\"period\":\"%s\"}]" % \

-           (lastUpdate, chartUpdateInterval)

+

+    # Format data into a JSON string.

     try:

-        fc = open(_DUMMY_OUTPUT_FILE, "w")

-        fc.write(sDate)

-        fc.close()

-    except Exception, exError:

-        print "%s write node file failed: %s" % (getTimeStamp(), exError)

+        jsData = json.loads("{}")

+        jsData.update({"date": lastUpdate})

+        jsData.update({"chartUpdateInterval": chartUpdateInterval})

+        jsData.update({"dataRequestInterval": dataRequestInterval})

+        jsData.update({"serverMode": _SERVER_MODE})

+        sData = "[%s]" % json.dumps(jsData)

+    except Exception as exError:

+        print("%s writeOutputFile: %s" % (getTimeStamp(), exError))

         return False

-    if _RELAY_SERVER:

-        # Write the entire node data response to the output data file.

-        try:

-            fc = open(_OUTPUT_DATA_FILE, "w")

-            fc.write(sData)

-            fc.close()

-        except Exception, exError:

-            print "%s write output file failed: %s" % \

-                  (getTimeStamp(), exError)

-            return False

-        if verboseDebug:

-            print "write output data file: %d bytes" % len(sData)

+    if verboseDebug:

+        print(sData)

+

+    try:

+        fc = open(_OUTPUT_DATA_FILE, "w")

+        fc.write(sData)

+        fc.close()

+    except Exception as exError:

+        print("%s write output file failed: %s" % (getTimeStamp(), exError))

+        return False

     return True

 ## end def

@@ -335,7 +338,7 @@ def setNodeStatus(updateSuccess):

         # Set status and send a message to the log if the node was

         # previously offline and is now online.

         if not nodeOnline:

-            print '%s aredn node online' % getTimeStamp()

+            print('%s aredn node online' % getTimeStamp())

             nodeOnline = True

     else:

         # The last attempt failed, so update the failed attempts

@@ -394,27 +397,27 @@ def createGraph(fileName, dataItem, gLabel, gTitle, gStart,

     if addTrend == 0:

         strCmd += "LINE1:dSeries#0400ff "

     elif addTrend == 1:

-        strCmd += "CDEF:smoothed=dSeries,%s,TREND LINE3:smoothed#ff0000 " \

+        strCmd += "CDEF:smoothed=dSeries,%s,TREND LINE2:smoothed#006600 " \

                   % trendWindow[gStart]

     elif addTrend == 2:

         strCmd += "LINE1:dSeries#0400ff "

-        strCmd += "CDEF:smoothed=dSeries,%s,TREND LINE3:smoothed#ff0000 " \

+        strCmd += "CDEF:smoothed=dSeries,%s,TREND LINE2:smoothed#006600 " \

                   % trendWindow[gStart]

     if verboseDebug:

-        print "%s" % strCmd # DEBUG

+        print("%s" % strCmd) # DEBUG

     # Run the formatted rrdtool command as a subprocess.

     try:

         result = subprocess.check_output(strCmd, \

                      stderr=subprocess.STDOUT,   \

                      shell=True)

-    except subprocess.CalledProcessError, exError:

-        print "rrdtool graph failed: %s" % (exError.output)

+    except subprocess.CalledProcessError as exError:

+        print("rrdtool graph failed: %s" % (exError.output))

         return False

     if debugOption:

-        print "rrdtool graph: %s\n" % result,

+        print("rrdtool graph: %s\n" % result.decode('utf-8'), end='')

     return True

 ##end def

@@ -456,7 +459,7 @@ def generateGraphs():

                 'SNR\ -\ Past\ Year', 'end-12months', 0, 0, 2, autoScale)

     if debugOption:

-        #print # print a blank line to improve readability when in debug mode

+        #print() # print a blank line to improve readability when in debug mode

         pass

 ##end def

@@ -482,15 +485,17 @@ def getCLarguments():

             try:

                 dataRequestInterval = abs(int(sys.argv[index + 1]))

             except:

-                print "invalid polling period"

+                print("invalid polling period")

                 exit(-1)

             index += 1

         elif sys.argv[index] == '-u':

             arednNodeUrl = sys.argv[index + 1]

+            if arednNodeUrl.find('http://') < 0:

+                arednNodeUrl = 'http://' + arednNodeUrl

             index += 1

         else:

             cmd_name = sys.argv[0].split('/')

-            print "Usage: %s [-d] [-v] [-p seconds] [-u url]" % cmd_name[-1]

+            print("Usage: %s [-d] [-v] [-p seconds] [-u url]" % cmd_name[-1])

             exit(-1)

         index += 1

 ##end def

@@ -504,9 +509,10 @@ def main():

     global dataRequestInterval

     signal.signal(signal.SIGTERM, terminateAgentProcess)

+    signal.signal(signal.SIGINT, terminateAgentProcess)

-    print '%s starting up arednsig agent process' % \

-                  (getTimeStamp())

+    print('%s starting up arednsig agent process' % \

+                  (getTimeStamp()))

     # last time output JSON file updated

     lastDataRequestTime = -1

@@ -520,9 +526,9 @@ def main():

     ## Exit with error if rrdtool database does not exist.

     if not os.path.exists(_RRD_FILE):

-        print 'rrdtool database does not exist\n' \

+        print('rrdtool database does not exist\n' \

               'use createArednsigRrd script to ' \

-              'create rrdtool database\n'

+              'create rrdtool database\n')

         exit(1)

     ## main loop

@@ -538,21 +544,23 @@ def main():

             result = True

             # Get the data string from the device.

-            sData = getArednNodeData()