Unable to get previous value of Template item by trigger

[reddysk]

Hello,

i am fighting with configuration of trigger on item when I need to publish last and previous value.

Even I went over all possible and impossible Zabbix forum articles even outside this forum I haven't found the right solution.


At the end I tried all possible options I derivate from all advises and tried:

Last value: {ITEM.LASTVALUE1}; All values: {ITEM.LASTVALUE} - [{?last(/{HOST.HOST}/{ITEM.KEY1},#2)}] - {?last(/{HOST.HOST}/{ITEM.KEY1},#2)} - last(/{HOST.HOST}/{ITEM.KEY1},#2) - {{HOST.HOST}:{ITEM.KEY}.last()} - {ITEM.VALUE1} to {ITEM.VALUE2}

I got:

Last value: 36; All values: 36 - [{?last(/localhost/{ITEM.KEY1},#2)}] - {?last(/CZCHOWS6831.prg-dc.dhl.com/{ITEM.KEY1},#2)} - last(/localhost/{ITEM.KEY1},#2) - {localhost:{ITEM.KEY}.last()} - 36 to *UNKNOWN*

Any advise please?

Running on Zabbix 6.4.10 appliance image.


Thanks in advance, Cheers, Reddy

[cyber]

{ITEM.LASTVALUE1} - returns last value, no option to point to second or third... those numbers there point to first item, second item, third item... used in expression...
{ITEM.KEY1} - returns they key of item, not a value. number as above, point to different keys, not to value...

{?last(/{HOST.HOST}/{ITEM.KEY},#2)} - close...but add all that to "Event name" field in trigger config, not to "trigger name" ...

[reddysk]

Cyber, I am trying that in Operational data, not in trigger name.

Will try this and will see. Pending issue to initiate the trigger.
Last value: {ITEM.LASTVALUE1}; Previous value: {?last(/{HOST.HOST}/{ITEM.KEY},#2)}

[reddysk]

So it doesn't work:

Last value: 40; Previous value: {?last(/localhost/{ITEM.KEY},#2)}

[PeterZielony]

where does it need to be published: email/webhook?

[reddysk]

Peter, in both. But As mentioned above, I wanted to have the information in Operational data of trigger.

[GarrettCO]

I am having very similar issue where no trigger is firing from "OK" to "Problem". Regardless of the documentation example this expression sample doesn't trigger and action when sending an SNMPTRAP



Using the following to send test trap
# snmptrap -v 2c -c public localhost 0 0 linkUp.0 s 0

[PeterZielony]

With Webhook it would be doable (email a bit harder - but you would have to do some scripting outside from frontend for emails)- you can write javascript to obtain previous value based on triggerID.

https://www.zabbix.com/documentation...ce/trigger/get

then get expandExpression and choose what you need to query. Use the second API function to obtain #2 value for this item
https://www.zabbix.com/documentation...ce/history/get

and at the end - send msg via webhook as normal with both values.

this sounds a bit tricky but doable - specially for webhooks. There is also a possibility that last #2 by the time you get it - it won't be #2 anymore so you would have to figure out how to get the previous one.

in nutshell - query zabbix itself for the previous value but you need to build logic to make sure #2 is the right one.

Don't have solution in hand - but worth looking at querying via api using webhook before sending it further

[cyber]

TBH, I have not done much with expression macros, so I did some testing now...
Using very simple testitem


and very simple trigger

last(/host/testitem)>0

What seems to be working, is setting trigger event name to

testitem trigger, item value {ITEM.LASTVALUE} - Prev value: {?last(//testitem,#2)}

using {ITEM.KEY} in expression macro gives error, even if https://www.zabbix.com/documentation...ed_by_location says

{?EXPRESSION}

→ Trigger event names

and https://www.zabbix.com/documentation...ression_macros says

{HOST.HOST<1-9>} and {ITEM.KEY<1-9>} macros are supported inside expression macros

using {ITEM.KEY} directly in event name field leaves it unresoved as docs say, its not usable there...

[reddysk]

Cyber, thank you, I will try it.
But please note that I am not trying to get it to name, but to Operational data

[cyber]

I am having very similar issue where no trigger is firing from "OK" to "Problem". Regardless of the documentation example this expression sample doesn't trigger and action when sending an SNMPTRAP



Using the following to send test trap
# snmptrap -v 2c -c public localhost 0 0 linkUp.0 s 0

Of course it does not work... if you go a nd look on your latest data, your item value for snmptrap[linkUp] item is not just "0".
it probably something like

20240131.093244 UDP: [source]:52463->[destination]:162
DISMAN-EVENT-MIB::sysUpTimeInstance = 0:0:00:00.00
SNMPv2-MIB::snmpTrapOID.0 = IF-MIB::linkUp.0

But this is completely offtopic, you should have started your own...

[cyber]

• 
  #6.1
  reddysk commented
  Today, 10:10
  Cyber, thank you, I will try it.
  But please note that I am not trying to get it to name, but to Operational data

aaragh.,. it is impossible to quote properly those "comments"... stupid feature..

I was about to edit my post... For opdata all that will not work.. only if you construct your trigger based messages properly (message templates for media)... There you can use much more macros than in trigger config...