Err executing working Python script from within SAM component on Raspbian

I am very much extremely green when it comes to both Raspberry Pis and Linux (till now I've lived within my SQL/PowerShell/C# world).

I have an Adafruit DHT temp sensor attached to a Pi 3 B, Python 2.7.9.

When I place the following code into a .py file within /tmp and call it while in a putty session, I am returned a line containing the data I am trying to pull, but when I put the same script in a Linux SAM component, I get:

"Testing on target node failed with 'Down' status ('Down' might be different if script exits with a different exit code).

#!/usr/bin/python

import sys

import Adafruit_DHT

humidity, temperature = Adafruit_DHT.read_retry(11, 4)

print 'Temp: {0:0.1f} C Humidity: {1:0.1f} %'.format(temperature, humidity)

notes:

Script Argument is just: python ${SCRIPT}

Script Working Directory: /tmp

I am using the pi account, credentials added in SolarWinds, of course.

additionally, I've discovered that it is bombing on the "humidity, temp....." line, not on the "import Adafruit_DHT" line

Why would the exact same code execute perfectly from the /tmp dir, logged in as "pi", yet fail when inside of Linux monitor component using same dir and credentials?

-Lost

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Accepted answers

gstadter

The good news:
successfully pulling data off of the DHT11/Rasp Pi into SolarWinds 8-)

The less good news, I suppose my post should actually be clarified as a need for understanding the reasoning behind why the script DOES work in the SAM component, just as it does in interactive putty session, but *seems to not work as expected within the script test mechanism of the template editor.

Whether or not I get to the bottom of that, my thanks to those who participated in the discussion thusfar.

All comments

jmeredith

I assume you have the agent installed and are managing the pi as a node with the agent. Correct?

Does it work with a simple bash script returning a couple of values?

aLTeReGo

The output of your script format does not appear to adhere to the requirements for SAM's Linux/Unix Script Monitor.

gstadter

yes sir, agent installed, though I have tried the template both 'Agent' and 'Agentless' modes of "Preferred Polling Method:".

I've not tried bash yet because I'd like to exhaust reasonable effort to understand why it's failing, considering that the code works flawlessly, without error when called by python and oh yeah, and the little fact that bash, perl, and python are foreign to me yet(that is changing quickly).

gstadter

The output does not match requirements of what SAM is expecting, I suspect, because the script is exiting unexpectedly early, hence, my need for understanding why it is doing so.

I do have these two lines immediately after the humidity/temp stat lines:

print "Statistic.TEMP2: 3\n"

print "Message.TEMP2: 4\n"

If I comment out the "humidity, temperature = Ada...." line, the script completes normally within the SAM component, showing the message and statistic.
It is when I un-comment-out the "humidity, temperature = Ada....." line that the SAM component errs.What I'm failing to understand is why it would bomb on that line if I can run the exact same code fine in putty, in same dir, as same user.

aLTeReGo

It may be easier to troubleshoot if you posted a screenshot of the scripts output. I will say that based upon your script, it does not appear that you are including a proper exit code so SAM knows if the script exited successfully or in error. That alone is likely to cause you some issues.

jmeredith

Where I was heading was just successfully passing data and being sure that connectivity is good and that passing simple values works. That ensures that the agent is working ok and all the plumbing is ok.

Sounds like you've done that, so now we're down to the external Adafruit_DHT module.

I'm assuming that the python path is working since you don't report an error with the import line.

Where I'm going with this is that when logged in as a user, you have a search path and a python path. Sometimes remote tools differ in these settings.

Also I'm not sure the scripts's working directory means that the agent actually does a "cd" to that directory to execute the script or it simply appends that directory to any filenames in the script. Maybe aLTeReGo ! can answer that.

gstadter

the environment and path questions you describe are exactly the initial things I seek to validate and understand in my efforts of troubleshooting this one.

gstadter

Executing via .py file in session:

Executing same script in SAM template with import not commented out, but call to the module commented out:

Executing same script in SAM template with import not commented out and call to the module not commented out: