empty lines in plug-in output

[[email protected]]

Hi all,

I recently moved from Nagios 3 to 4 and the first thing I noticed was that empty lines are translated to "\n".

So this test plugin

Code: Select all

#!/bin/sh
echo TEST
echo line 1
echo line 2
echo
echo line 4
exit 0

produces this output

Code: Select all

TEST
line 1
line 2
\nline 4

I couldn't find anything online about this behaviour. Is this a bug or a feature and if the latter can it be turned off?

Thanks,
Eli

[rkennedy]

I spoke with one of our developers, and he informed me that it shouldn't be converting a new line to \n. Could you file an issue for this on our GitHub? https://github.com/NagiosEnterprises/nagioscore/issues

[tmcdonald]

Confirmed on 4.1.1

[eloyd]

I'm slow today. Can someone tell me how this matters? I thought plugins should only be outputting one line anyway?

[tmcdonald]

Should, but it is not required:

Starting with version 3, Nagios will process plugins' multiline output, which should be formatted as:

SERVICE STATUS: First line of output | First part of performance data
Any number of subsequent lines of output, but note that buffers
may have a limited size | Second part of performance data, which
may have continuation lines, too

https://nagios-plugins.org/doc/guidelines.html#AEN33

I can think of good reasons why multi-line output might be needed (multiple disk/mount checks in one service (ugly but sometimes desired), event logs that return the log contents, a service which writes out the lyrics to Another Brick In The Wall, etc.) but in general I agree with the one-line thing. The issue here is that it appears to be showing a literal \n as two characters, instead of converting to <br />[/icode for display] or something. I vaguely recall an option to define this behavior, but I might be thinking of the CGI config option to allow HTML tags.

At any rate, C dev confirm buggy behavior so it'll be addressed. If we don't hear from OP I'll be filing this on their behalf.

[eloyd]

Thanks. I'll have to go look at that. I'm especially interested in seeing what happens with multi-line perf data.

[tmcdonald]

I'll get this filed tomorrow, and update accordingly!

Update: Ran into some more pressing matters, but it looks like someone beat me to it: https://github.com/NagiosEnterprises/na ... issues/137