#!/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 the Internet web server. 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 itemsq
# - update a round robin (rrdtool) database with the radiation data
# - periodically generate graphic charts for display in html documents
# - forward the radiation data to other services
# - 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
_MIRROR_SERVER = False
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 = "http://192.168.1.24"
# url if this is a mirror server
_PRIMARY_SERVER_URL = "http://73.157.139.23:7361" \
"/~pi/radmon/dynamic/radmonInputData.dat"
### 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
# used for detecting system faults and radiation monitor
# online or offline status
failedUpdateCount = 0
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():
"""
Sets 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 status of the the upstream device to "offline" and sends
blank data to the downstream clients.
Parameters:
dData - dictionary object containing weather data
Returns nothing.
"""
global stationOnline
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 message to log when process killed
Parameters: signal, frame - sigint parameters
Returns: nothing
"""
print '%s terminating radmon agent process' % \
(getTimeStamp())
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. The data is formatted
as an html document.
Parameters:
radiationMonitorUrl - url of radiation monitoring device
HttpRequesttimeout - how long to wait for device
to respond to http request
Returns a string containing the radiation data, or None if
not successful.
"""
global remoteDeviceReset
if _MIRROR_SERVER:
sUrl = _PRIMARY_SERVER_URL
else:
sUrl = radiationMonitorUrl
if remoteDeviceReset:
sUrl += "/reset"
else:
sUrl += "/rdata"
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 set the status of the device to offline.
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'
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:
lsData - a list object containing the radiation data
dData - a dictionary object containing the radiation data
Returns true if successful, false otherwise.
"""
result = True
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)
result = False
return result
##end def
def writeOutputDataFile(dData):
"""Write radiation data items to a JSON formatted file for use by
HTML documents.
Parameters:
lsData - a list object containing the data to be written
to the JSON 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']))
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'
# 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 file for use by mirror
servers.
Parameters:
sData - a string object containing the data string 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):
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:
failedUpdateCount += 1
if debugOption:
print 'radiation update failed'
if failedUpdateCount >= _MAX_FAILED_DATA_REQUESTS:
setStatusToOffline()
##end def
def updateDatabase(dData):
"""
Updates the rrdtool database by executing an rrdtool system command.
Formats 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
# Create the rrdtool update command.
strCmd = "rrdtool update %s %s:%s:%s" % \
(_RRD_FILE, dData['ELT'], dData['CPM'], SvPerHr)
if debugOption and False:
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 graph image file
dataItem - data item to be graphed
gLabel - string containing a graph label for the data item
gTitle - string containing a title for the graph
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 debugOption and False:
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 three possible arguments
-d turns on debug mode
-t sets the radiation device query interval
-u sets the url of the radiation monitoring device
Returns nothing.
"""
global debugOption, dataRequestInterval, radiationMonitorUrl
index = 1
while index < len(sys.argv):
if sys.argv[index] == '-d':
debugOption = 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:
print
#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')