my digitemp script doesn't work

[sonium]

Hi, I'm trying to access a digitemp sensor by cacti.

this is my script what should do the trick

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#!/bin/bash

echo -n temp:
digitemp -a -r750 | grep "C: " | awk '{ print $7}'

unfortunatly cacti only reads the output "temp:"

I think this comes from a to early reading abort.
"temp:" is printed immidiatly
but the second line, that reads the temperature from the sensor has a delay of 750ms .

any idea how to fix the problem?
[/code]

[rony]

What is a sample of the scripts output?

[sonium]

Code: Select all

sonium@ubuntu:~$ digitemp -r750 -a
DigiTemp v1.3 Copyright 1997-99 by Nexus Computing

Dec 25 11:22:16 Sensor 0 C: 3.19 F: 37.74

so, I tracked down the problem to the point that www-data had no access to /dev/ttyS0 where the digitemp interface is connected

if I run poller.php as www-data now everything works fine
but the runs by cron still don't success.

Is there a way to find out from wich user the script is executed?

[mludvig]

this is my script what should do the trick

Code: Select all

#!/bin/bash

echo -n temp:
digitemp -a -r750 | grep "C: " | awk '{ print $7}'

...
any idea how to fix the problem?

Just a hint - AWK is pretty powerfull. There's no need for echo and grep in your script. Instead do all your parsing directly in AWK:

Code: Select all

digitemp -a -r750 | awk '/C:/{print "temp: " $7}'

[ehall]

if I run poller.php as www-data now everything works fine
but the runs by cron still don't success.

Is there a way to find out from wich user the script is executed?

$ cat /etc/cron.d/cacti

[C42Ralf]

[...] I tracked down the problem to the point that www-data had no access to /dev/ttyS0 where the digitemp interface is connected

if I run poller.php as www-data now everything works fine
but the runs by cron still don't success.

I had quite a hard time to get my digitemp script to run. Main problems have been permissions and ownership.

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crw-rw----  1 root uucp 4, 64 2006-02-05 09:30 /dev/ttyS0

My digitemp.sh script couldn't read the interface (/dev/ttyS0), therefore I added the user wwwrun to the group uucp.

My script (I am using digitemp 3.3.2):

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#!/bin/sh
# read temperature of single sensor (celsius)
/usr/local/bin/digitemp -q -t $1 -c /usr/local/etc/.digitemprc | awk '/C:/{print $7}'

Next problem was the export of graphs, the user wwwrun couldn't write the graph files to my web folder. I solved this by adding group rights of the corresponding folder.

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# id wwwrun
uid=30(wwwrun) gid=8(www) Gruppen=8(www),14(uucp)
# chmod g+w /srv/www/htdocs/graphs/
# ls -ld /srv/www/htdocs/graphs/
drwxrwxr-x  2 www www 1208 2006-02-05 09:40 /srv/www/htdocs/graphs/

I am still struggling with the database update and the graph template.