#!/usr/bin/python -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.
#
# Module: radmonAgent.py
#
# Description: This module acts as an agent between the radiation monitoring
# device and Internet web services. The agent periodically sends an http
# request to the radiation monitoring device and processes the response from
# the device and performs a number of operations:
# - conversion of data items
# - update a round robin (rrdtool) database with the radiation data
# - periodically generate graphic charts for display in html documents
# - write the processed weather data to a JSON file for use by html
# documents
#
# Copyright 2015 Jeff Owrey
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see http://www.gnu.org/license.
#
# Revision History
# * v20 released 15 Sep 2015 by J L Owrey; first release
# * v21 released 27 Nov 2017 by J L Owrey; bug fixes; updates
# * v22 released 03 Mar 2018 by J L Owrey; improved code readability;
# improved radmon device offline status handling
# * v23 released 16 Nov 2018 by J L Owrey: improved fault handling
# and data conversion
import os
import urllib2
import sys
import signal
import subprocess
import multiprocessing
import time
import calendar
_USER = os.environ['USER']
### DEFAULT RADIATION MONITOR URL ###
# ip address of radiation monitoring device
_DEFAULT_RADIATION_MONITOR_URL = "{your radiation monitor url}"
### FILE AND FOLDER LOCATIONS ###
# folder for containing dynamic data objects
_DOCROOT_PATH = "/home/%s/public_html/radmon/" % _USER
# folder for charts and output data file
_CHARTS_DIRECTORY = _DOCROOT_PATH + "dynamic/"
# location of data input file
_INPUT_DATA_FILE = _DOCROOT_PATH + "dynamic/radmonInputData.dat"
# location of data output file
_OUTPUT_DATA_FILE = _DOCROOT_PATH + "dynamic/radmonOutputData.js"
# database that stores weather data
_RRD_FILE = "/home/%s/database/radmonData.rrd" % _USER
### GLOBAL CONSTANTS ###
# max number of failed data requests allowed
_MAX_FAILED_DATA_REQUESTS = 2
# interval in seconds between data requests to radiation monitor
_DEFAULT_DATA_REQUEST_INTERVAL = 5
# defines how often the charts get updated in seconds
_CHART_UPDATE_INTERVAL = 300
# defines how often the database gets updated
_DATABASE_UPDATE_INTERVAL = 30
# number seconds to wait for a response to HTTP request
_HTTP_REQUEST_TIMEOUT = 3
# standard chart width in pixels
_CHART_WIDTH = 600
# standard chart height in pixels
_CHART_HEIGHT = 150
### GLOBAL VARIABLES ###
# turn on or off of verbose debugging information
debugOption = False
verboseDebug = False
# The following two items are used for detecting system faults
# and radiation monitor online or offline status.
# count of failed attempts to get data from radiation monitor
failedUpdateCount = 0
# detected status of radiation monitor device
stationOnline = True
# status of reset command to radiation monitor
remoteDeviceReset = False
# ip address of radiation monitor
radiationMonitorUrl = _DEFAULT_RADIATION_MONITOR_URL
# web update frequency
dataRequestInterval = _DEFAULT_DATA_REQUEST_INTERVAL
### PRIVATE METHODS ###
def getTimeStamp():
"""
Set the error message time stamp to the local system time.
Parameters: none
Returns: string containing the time stamp
"""
return time.strftime( "%m/%d/%Y %T", time.localtime() )
##end def
def setStatusToOffline():
"""Set the detected status of the radiation monitor to
"offline" and inform downstream clients by removing input
and output data files.
Parameters: none
Returns: nothing
"""
global stationOnline
# Inform downstream clients by removing input and output
# data files.
if os.path.exists(_INPUT_DATA_FILE):
os.remove(_INPUT_DATA_FILE)
if os.path.exists(_OUTPUT_DATA_FILE):
os.remove(_OUTPUT_DATA_FILE)
# If the radiation monitor was previously online, then send
# a message that we are now offline.
if stationOnline:
print '%s radiation monitor offline' % getTimeStamp()
stationOnline = False
##end def
def terminateAgentProcess(signal, frame):
"""Send a message to log when the agent process gets killed
by the operating system. Inform downstream clients
by removing input and output data files.
Parameters:
signal, frame - dummy parameters
Returns: nothing
"""
print '%s terminating radmon agent process' % \
(getTimeStamp())
# Inform downstream clients by removing input and output
# data files.
if os.path.exists(_OUTPUT_DATA_FILE):
os.remove(_OUTPUT_DATA_FILE)
if os.path.exists(_INPUT_DATA_FILE):
os.remove(_INPUT_DATA_FILE)
sys.exit(0)
##end def
### PUBLIC METHODS ###
def getRadiationData():
"""Send http request to radiation monitoring device. The
response from the device contains the radiation data as
unformatted ascii text.
Parameters: none
Returns: a string containing the radiation data if successful,
or None if not successful
"""
global remoteDeviceReset
sUrl = radiationMonitorUrl
if remoteDeviceReset:
sUrl += "/reset" # reboot the radiation monitor
else:
sUrl += "/rdata" # request data from the monitor
try:
conn = urllib2.urlopen(sUrl, timeout=_HTTP_REQUEST_TIMEOUT)
# Format received data into a single string.
content = ""
for line in conn:
content += line.strip()
del conn
except Exception, 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.
if debugOption:
print "http error: %s" % exError
return None
return content
##end def
def parseDataString(sData, dData):
"""Parse the radiation data JSON string from the radiation
monitoring device 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:
sTmp = sData[2:-2]
lsTmp = sTmp.split(',')
except Exception, exError:
print "%s parseDataString: %s" % (getTimeStamp(), exError)
return False
# Load the parsed data into a dictionary for easy access.
for item in lsTmp:
if "=" in item:
dData[item.split('=')[0]] = item.split('=')[1]
dData['status'] = 'online'
# Verfy the expected number of data items have been received.
if len(dData) != 6:
print "%s parse failed: corrupted data string" % getTimeStamp()
return False;
return True
##end def
def convertData(dData):
"""Convert individual radiation data items as necessary.
Parameters:
dData - a dictionary object containing the radiation data
Returns: True if successful, False otherwise
"""
try:
# Convert the UTC timestamp provided by the radiation monitoring
# device to epoch local time in seconds.
ts_utc = time.strptime(dData['UTC'], "%H:%M:%S %m/%d/%Y")
epoch_local_sec = calendar.timegm(ts_utc)
dData['ELT'] = epoch_local_sec
# Uncomment the code line below to use a timestamp generated by the
# requesting server (this) instead of the timestamp provided by the
# radiation monitoring device. Using the server generated timestamp
# prevents errors that occur when the radiation monitoring device
# fails to synchronize with a valid NTP time server.
#dData['ELT'] = time.time()
dData['Mode'] = dData['Mode'].lower()
dData['uSvPerHr'] = '%.2f' % float(dData.pop('uSv/hr'))
except Exception, exError:
print "%s data conversion failed: %s" % (getTimeStamp(), exError)
return False
return True
##end def
def writeOutputDataFile(dData):
"""Write radiation 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.
Parameters:
dData - a dictionary object containing the data to be written
to the output data file
Returns: True if successful, False otherwise
"""
# Set date to current time and data
dData['date'] = time.strftime("%m/%d/%Y %T", time.localtime(dData['ELT']))
# Remove unnecessary data items.
dTemp = dict(dData)
dTemp.pop('ELT')
dTemp.pop('UTC')
# Format the weather data as string using java script object notation.
sData = '[{'
for key in dTemp:
sData += '\"%s\":\"%s\",' % (key, dData[key])
sData = sData[:-1] + '}]\n'
if verboseDebug:
print sData
# Write the string to the output data file for use by html documents.
try:
fc = open(_OUTPUT_DATA_FILE, "w")
fc.write(sData)
fc.close()
except Exception, exError:
print "%s writeOutputDataFile: %s" % (getTimeStamp(), exError)
return False
return True
## end def
def writeInputDataFile(sData):
"""Write raw data from radiation monitor to the input data file.
This file may then be accessed by downstream mirror servers.
Parameters:
sData - a string object containing the raw data from
the radiation monitor
Returns: True if successful, False otherwise
"""
sData += "\n"
try:
fc = open(_INPUT_DATA_FILE, "w")
fc.write(sData)
fc.close()
except Exception, exError:
print "%s writeInputDataFile: %s" % (getTimeStamp(), exError)
return False
return True
##end def
def setStationStatus(updateSuccess):
"""Detect if radiation monitor is offline or not available on
the network. After a set number of attempts to get data
from the monitor set a flag that the station is offline.
Parameters:
updateSuccess - a boolean that is True if data request
successful, False otherwise
Returns: nothing
"""
global failedUpdateCount, stationOnline
if updateSuccess:
failedUpdateCount = 0
# Set status and send a message to the log if the station was
# previously offline and is now online.
if not stationOnline:
print '%s radiation monitor online' % getTimeStamp()
stationOnline = True
if debugOption:
print 'radiation update successful'
else:
# The last attempt failed, so update the failed attempts
# count.
failedUpdateCount += 1
if debugOption:
print 'radiation update failed'
if failedUpdateCount >= _MAX_FAILED_DATA_REQUESTS:
# Max number of failed data requests, so set
# monitor status to offline.
setStatusToOffline()
##end def
def updateDatabase(dData):
"""
Update the rrdtool database by executing an rrdtool system command.
Format the command using the data extracted from the radiation
monitor response.
Parameters: dData - dictionary object containing data items to be
written to the rr database file
Returns: True if successful, False otherwise
"""
global remoteDeviceReset
# The RR database stores whole units, so convert uSv to Sv.
SvPerHr = float(dData['uSvPerHr']) * 1.0E-06
# Format the rrdtool update command.
strCmd = "rrdtool update %s %s:%s:%s" % \
(_RRD_FILE, dData['ELT'], dData['CPM'], SvPerHr)
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, exError:
print "%s: rrdtool update failed: %s" % \
(getTimeStamp(), exError.output)
if exError.output.find("illegal attempt to update using time") > -1:
remoteDeviceReset = True
print "%s: rebooting radiation monitor" % (getTimeStamp())
return False
else:
if debugOption:
print 'database update sucessful'
return True
##end def
def createGraph(fileName, dataItem, gLabel, gTitle, gStart,
lower, upper, addTrend, autoScale):
"""Uses rrdtool to create a graph of specified weather data item.
Parameters:
fileName - name of file containing the graph
dataItem - data item to be graphed
gLabel - string containing a graph label for the data item
gTitle - string containing a title for the graph
gStart - beginning time of the graphed data
lower - lower bound for graph ordinate #NOT USED
upper - upper bound for graph ordinate #NOT USED
addTrend - 0, show only graph data
1, show only a trend line
2, show a trend line and the graph data
autoScale - if True, then use vertical axis auto scaling
(lower and upper parameters are ignored), otherwise use
lower and upper parameters to set vertical axis scale
Returns: True if successful, False otherwise
"""
gPath = _CHARTS_DIRECTORY + fileName + ".png"
trendWindow = { 'end-1day': 7200,
'end-4weeks': 172800,
'end-12months': 604800 }
# Format the rrdtool graph command.
# Set chart start time, height, and width.
strCmd = "rrdtool graph %s -a PNG -s %s -e now -w %s -h %s " \
% (gPath, gStart, _CHART_WIDTH, _CHART_HEIGHT)
# Set the range and scaling of the chart y-axis.
if lower < upper:
strCmd += "-l %s -u %s -r " % (lower, upper)
elif autoScale:
strCmd += "-A "
strCmd += "-Y "
# Set the chart ordinate label and chart title.
strCmd += "-v %s -t %s " % (gLabel, gTitle)
# Show the data, or a moving average trend line over
# the data, or both.
strCmd += "DEF:dSeries=%s:%s:LAST " % (_RRD_FILE, dataItem)
if addTrend == 0:
strCmd += "LINE1:dSeries#0400ff "
elif addTrend == 1:
strCmd += "CDEF:smoothed=dSeries,%s,TREND LINE3:smoothed#ff0000 " \
% trendWindow[gStart]
elif addTrend == 2:
strCmd += "LINE1:dSeries#0400ff "
strCmd += "CDEF:smoothed=dSeries,%s,TREND LINE3:smoothed#ff0000 " \
% trendWindow[gStart]
if verboseDebug:
print "%s\n" % 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)
return False
if debugOption:
print "rrdtool graph: %s" % result
return True
##end def
def generateGraphs():
"""Generate graphs for display in html documents.
Parameters: none
Returns: nothing
"""
autoScale = False
createGraph('24hr_cpm', 'CPM', 'counts\ per\ minute',
'CPM\ -\ Last\ 24\ Hours', 'end-1day', 0, 0, 2, autoScale)
createGraph('24hr_svperhr', 'SvperHr', 'Sv\ per\ hour',
'Sv/Hr\ -\ Last\ 24\ Hours', 'end-1day', 0, 0, 2, autoScale)
createGraph('4wk_cpm', 'CPM', 'counts\ per\ minute',
'CPM\ -\ Last\ 4\ Weeks', 'end-4weeks', 0, 0, 2, autoScale)
createGraph('4wk_svperhr', 'SvperHr', 'Sv\ per\ hour',
'Sv/Hr\ -\ Last\ 4\ Weeks', 'end-4weeks', 0, 0, 2, autoScale)
createGraph('12m_cpm', 'CPM', 'counts\ per\ minute',
'CPM\ -\ Past\ Year', 'end-12months', 0, 0, 2, autoScale)
createGraph('12m_svperhr', 'SvperHr', 'Sv\ per\ hour',
'Sv/Hr\ -\ Past\ Year', 'end-12months', 0, 0, 2, autoScale)
##end def
def getCLarguments():
"""Get command line arguments. There are four possible arguments
-d turns on debug mode
-v turns on verbose debug mode
-t sets the radiation device query interval
-u sets the url of the radiation monitoring device
Returns: nothing
"""
global debugOption, verboseDebug, dataRequestInterval, \
radiationMonitorUrl
index = 1
while index < len(sys.argv):
if sys.argv[index] == '-d':
debugOption = True
elif sys.argv[index] == '-v':
debugOption = True
verboseDebug = True
elif sys.argv[index] == '-t':
try:
dataRequestInterval = abs(int(sys.argv[index + 1]))
except:
print "invalid polling period"
exit(-1)
index += 1
elif sys.argv[index] == '-u':
radiationMonitorUrl = sys.argv[index + 1]
index += 1
else:
cmd_name = sys.argv[0].split('/')
print "Usage: %s [-d] [-t seconds] [-u url}" % cmd_name[-1]
exit(-1)
index += 1
##end def
def main():
"""Handles timing of events and acts as executive routine managing
all other functions.
Parameters: none
Returns: nothing
"""
signal.signal(signal.SIGTERM, terminateAgentProcess)
print '%s starting up radmon agent process' % \
(getTimeStamp())
# last time output JSON file updated
lastDataRequestTime = -1
# last time charts generated
lastChartUpdateTime = - 1
# last time the rrdtool database updated
lastDatabaseUpdateTime = -1
## Get command line arguments.
getCLarguments()
## Exit with error if rrdtool database does not exist.
if not os.path.exists(_RRD_FILE):
print 'rrdtool database does not exist\n' \
'use createWeatherRrd script to ' \
'create rrdtool database\n'
exit(1)
## main loop
while True:
currentTime = time.time() # get current time in seconds
# Every web update interval request data from the radiation
# monitor and process the received data.
if currentTime - lastDataRequestTime > dataRequestInterval:
lastDataRequestTime = currentTime
dData = {}
result = True
# Get the data string from the device.
sData = getRadiationData()
if sData == None:
result = False
# If successful parse the data.
if result:
result = parseDataString(sData, dData)
# If parsing successful, convert the data.
if result:
result = convertData(dData)
# If conversion successful, write data to data files.
if result:
writeInputDataFile(sData)
writeOutputDataFile(dData)
# At the rrdtool database update interval, update the database.
if currentTime - lastDatabaseUpdateTime > \
_DATABASE_UPDATE_INTERVAL:
lastDatabaseUpdateTime = currentTime
## Update the round robin database with the parsed data.
updateDatabase(dData)
# Set the station status to online or offline depending on the
# success or failure of the above operations.
setStationStatus(result)
# At the chart generation interval, generate charts.
if currentTime - lastChartUpdateTime > _CHART_UPDATE_INTERVAL:
lastChartUpdateTime = currentTime
p = multiprocessing.Process(target=generateGraphs, args=())
p.start()
# Relinquish processing back to the operating system until
# the next update interval.
elapsedTime = time.time() - currentTime
if debugOption and not verboseDebug:
print
if verboseDebug:
print "processing time: %6f sec\n" % elapsedTime
remainingTime = dataRequestInterval - elapsedTime
if remainingTime > 0.0:
time.sleep(remainingTime)
## end while
return
## end def
if __name__ == '__main__':
try:
main()
except KeyboardInterrupt:
print '\n',
terminateAgentProcess('KeyboardInterrupt','Module')