How to use arithmetical operators in triggers

[jpawlowski]

I'd like to calculate a delta between two items of a host and like the trigger to be TRUE if the delta is over the limit.

I tried this trigger:

({Host:check_url_lastmod[http://example.com].now(0)}-{Host:check_url_lastmod[http://example.com].last(0)})>21600

Unfortunately the system rejects this trigger to be false. so how could I realize it?

[Alexei]

Use function change(). Please, read ZABBIX Manual: http://www.zabbix.com/manual/v1.1/config_triggers.php

[jpawlowski]

could you please give me an example? I have no idea how this function should solve my problem...

I don't want to check the difference between last and previous value. I would like to check if the timecode in seconds from that value od that item is older than 6 hours. btw I also do not want to be notified if the item hasn't been checked for longer than 6 hours...

maybe I'm too stupid today...

[Alexei]

It seems I misunderstood your question. My solution:

{Host:check_url_lastmod[http://example.com].count(21600)}=1

[jpawlowski]

no that would only verify that I retrieved any value since the last 6 hours. that's not my point.

I simply want to calculate the delta of time from the current moment to that time an internet URL has been last modified. I want to be notified if the URL hasn't been modified since 6 hours.

so i wrote that script which returns the HTTP-Header "Last-Modified" in seconds since 00:00:00 UTC, January 1, 1970.

this value is stored in zabbix and I want zabbix to compare this value with the current time in seconds 00:00:00 UTC, January 1, 1970.

Manually I would now calculate this:

1117552844sec - 1117539919sec = 12925 sec

finally the triggers expression should check if the result is larger than 21600 seconds (6 hours).

I thought I could use your function "now(0)" as it is described in your documentation. So why did you implement this function? If I could not use it I don't understand the sense...

[Alexei]

I tried this trigger:

({Host:check_url_lastmod[http://example.com].now(0)}-{Host:check_url_lastmod[http://example.com].last(0)})>21600

Unfortunately the system rejects this trigger to be false. so how could I realize it?The trigger expression should work. Is this trigger in UNKNOWN or FALSE state?

[jpawlowski]

neither UNKNOWN nor false...
in fact I can't create the trigger but get the failure

"ERROR:Invalid trigger expression"

I would add it manually to the database but unfortunately this field is of binary type blob :-/

btw of course I use the current alpha10...

[jpawlowski]

does nobody has any idea?

I just changed my script passing the differnce to me but I think it's really unlovely not to have the real current timestamp...

so again, why is there a function now() if I can't use it in any case?


regards,
Julian

[jpawlowski]

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