NOAA Weather Probe Example

It is now easier than ever to build command-line probes. This example retrieves temperature data from the US NOAA weather feed in a particular city.

How does this probe work?

Right-click a device and choose Select Probe.
Select the Weather Service-Temp probe from the Miscellaneous/Test category.
Enter the city code for the closest weather station (for example, KLEB, Lebanon Municipal Airport). The Status window shows the name of the weather station, with a chartable value for the temperature reading.

Under the covers, Intermapper launches a Python program to contact the weather service, retrieve the meteorological conditions for the indicated city, and parses the XML response to retrieve the temperature. (There is a lot more information in the Weather Service feed; you can extend the program to display more information.) The following are some features of this probe:

The ${PYTHON} macro provides the path to the built-in python interpreter of Intermapper DataCenter no matter what platform you use. For example, the probe can now use the following:

cmd = "${PYTHON} program.py"

Intermapper substitutes the proper path to invoke Python, whether on Microsoft Windows, macOS, or Linux systems.

NOTE:
To use this macro, the Intermapper DataCenter (IMDC) must be installed. IMDC is installed automatically with Intermapper 5.2 on Microsoft Windows and OSX systems; Linux systems require a separate installation for IMDC.
You can include the script directly in the probe file text.This makes it easier to write scripts and keep the probe file in sync. To do this, use the <tool:program-name> section in your probe file. The example below contains a program named noaa-weather.py. When Intermapper loads the probe, it parses out this section and saves it in a folder within the Tools directory of Intermapper Settings. Programs in the <tools> section can also save private files in that directory.
The example probe file uses a few Python libraries. For example, urllib2 makes it easy to make queries from web services. It includes a few straightforward calls to build a URL, issue it, and retrieve the results.

The probe uses the xml.dom.minidom library to parse XML data returned from the NOAA web service. For more information on this library, see Chapter 9 of Dive into Python.

NOAA Temperature Probe

To use this probe, copy the text below, paste it to a text editor, save it to a text file, and click File > Import> Probe... in Intermapper.

<!--
Weather Service Temperature - Retrieve the temperature from the NOAA weather XML
(com.dartware.tool.noaa.txt) Copyright© Fortra, LLC.
Please feel free to use this as a base for further development.
-->

<header>
     type = "cmd-line"
     package = "com.dartware"
     probe_name = "tool.noaa"
     human_name = "Weather Service-Temperature"
     version = "1.3"
     address_type = "IP"
     display_name = "Miscellaneous/Test/Weather Service-Temp"
 </header>

<description>
\GB\Retrieve the current temperature\p\

This probe retrieves the current temperature from the NOAA weather feed. To see the proper city code, visit:

\u4=http://www.weather.gov/xml/current_obs/\http://www.weather.gov/xml/current_obs/\p0\
</description>

<parameters>
     "Weather Station" = "KLEB"
</parameters>

<command-line>
      path=""
      cmd="${PYTHON} noaa_weather.py"
      arg="${Weather Station}"
</command-line>

<command-exit>
      -- These are the exit codes used by Nagios plugins
        down: ${EXIT_CODE}=4
        critical: ${EXIT_CODE}=3
        alarm: ${EXIT_CODE}=2
        warn: ${EXIT_CODE}=1
        okay: ${EXIT_CODE}=0
</command-exit>

<command-display>
\b5\ Temperature for $loc\p0\
  Temperature: $temp \3g\degrees F\p0\
</command-display>

<tool:noaa_weather.py>

# noaa_weather.py
# Scan the XML results from NOAA's XML feeds
# e.g., http://www.weather.gov/xml/current_obs/KLEB.xml # for relevant weather-related information.
# 25 Mar 2009 -reb
import os
import re
import sys
import getopt
import urllib.request, urllib.parse, urllib.error
from xml.dom import minidom

# httplib.HTTPConnection.debuglevel = 1 # force debugging....
# options are: station

try:
       opts, args = getopt.getopt(sys.argv[1:], "")
except getopt.GetoptError as err:
       searchString = "getopt error %d" % (err)

station = args[0]
userAgent = "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_ 5; en-us) AppleWebKit/525.18 (KHTML, like Gecko) 
             Version/3.1.2 Safari/525.20.1"
noaaString = "http://www.weather.gov/xml/current_obs/%s.xml"
noaaString = noaaString % (urllib.parse.quote_plus(station))

# print noaaString;
retcode = 4;
try:
      request = urllib.request.Request(noaaString)
      opener = urllib.request.build_opener()
      request.add_header('User-Agent', userAgent)
      usock= opener.open(request)
#	print buf
except IOError as e:
      if hasattr(e, 'reason'):
                    resp = 'We failed to reach a server. '
                    reason = 'Reason: ' + 'Wrong host name?' # e.reason[1]
      elif hasattr(e, 'code'):
                    resp = 'The server couldn\'t fulfill the request. '
                    reason = 'Error code: '+ str(e.code)
      print("\{ $temp := '%s', $loc := 'Unknown' } %s" % (0, resp + reason))
      sys.exit(retcode) # make it look down

retcode = 0 # looks like it'll succeed
xmldoc = minidom.parse(usock)
tempList = xmldoc.getElementsByTagName('temp_f')
tempElem = tempList[0]
tempval = tempElem.firstChild.data
loclist = xmldoc.getElementsByTagName('location')
locval = loclist[0].firstChild.data
print("\{ $temp := '%s', $loc := '%s' }%s" % (tempval, locval, tempval + ' degrees at ' + locval))
sys.exit(retcode)
</tool:noaa_weather.py>