1.4.1 ExternalChecks problems

[eran]

After upgrading to 1.4.1 I noticed that triggers related to external checks didn't behave properly, they seem to turn on and off without any good reason.

So I tried modifying one such trigger and kept getting "incorrect expression errors", so I went a step back to the items and had the same problem there, until I discovered that if I replaced the parenthesis in the item key with square brackets I could save the item, however now it doesn't work anymore. And the item is now listed as "unsupported"

This is a sample item that used to work with previous versions:
GetTodaysStats(Send Mail)

This is how it looks after I modified it and it stopped working
GetTodaysStats[Send Mail]

This is a sample trigger that's behaving weird:
{WFPost:GetTodaysStats(Send_Fail Mail).sum(#2)}/{WFPost:GetTodaysStats(Send Mail).sum(#2)}>0.5 | {WFPost:GetTodaysStats(Send_Fail Mail).sum(#6)}/{WFPost:GetTodaysStats(Send Mail).sum(#6)}>0.2


This problem is urgent since it's monitoring a critical system.

Thanks,
Eran

[Alexei]

We have more strict parsing of triggers expressions in 1.4.1, this affected syntax of item keys as well. If "GetTodaysStats(Send_Fail_Mail)" is a user parameter, you may rename it to GetTodaysStats[Send_Fail_Mail] in ZABBIX frontend and in agent's configuration file. It should work.

[eran]

it's not a user parameter, it's an external script and I need it to have two separate parameters on the command line, so I can't replace the space with underscore.

For now I went back to the ver. 1.4 of the GUI so I could change the square brackets back to parenthesis but the triggers are still behaving incorrectly and are triggered ON even through they shouldn't be.

Just so you can see for your self that the above trigger should not be ON. These are the last values for the send_fail items:
2007.Jul.02 04:24:46 1
2007.Jul.02 04:23:41 1
2007.Jul.02 04:13:40 5
2007.Jul.02 04:03:41 1
2007.Jul.02 03:53:41 1
2007.Jul.02 03:43:40 2
2007.Jul.02 03:33:41 2

And these are the last values for the send item:
2007.Jul.02 04:24:47 75
2007.Jul.02 04:23:39 151
2007.Jul.02 04:13:40 207
2007.Jul.02 04:03:39 192
2007.Jul.02 03:53:40 180
2007.Jul.02 03:43:40 160
2007.Jul.02 03:33:40 239

[Alexei]

Please, check the latest manual. ZABBIX behaves according to priorities of arithmetical and logical operations. Add brackets to make calculations more predictable.

[eran]

Thanks Alexei, putting parenthesis there did fix solve the problem, but I can swear the same expressions worked in previous versions. It's wierd.

May I comment though that the operator precedence is not natural at all. In all programming languages I know logical operators (and, or) have lower precedence than comparison operators (=, <>, etc.). It doesn't really make sense that zabbix would have a different precedence.

For example, in C the order is: http://www.difranco.net/cop2220/op-prec.htm

Eran

[eran]

by the way, is there a solution to the space in the external script parameters (from my initial post)?

[Alexei]

I actually followed C logic for trigger expressions. It seems that I incorrectly set precedence for logical | and & higher than for <>=#. It is fixed in pre 1.4.2 code, so your expression will work even without brackets. Documentation updated as well.