Format error or unsupported operator message in the dashboard

[varas]

Hello,

First of all I would like to thank Zabbix team for the great monitoring product!

I've found strange problem on last Zabbix server upgrade to version 2.2.8

We are monitoring multimedia system and watching if m3u8 file is created and it is updated permanently. So python script parses playlist file and returns md5sum to zabbix agentd.

Problems starts when playlist file is removed or somehow damaged, then we return int(100) to the server. Zabbix server recognizes the problem, performs action and reloads the service. Service starts to work, answer 100 is changed with md5sum of the real file we all are happy

But strange thing happens after this - the trigger message of the previous item is left in the dashboard for ever with question icon saying: "Format error or unsupported operator. Exp: [943e686ae8ee3c9e2d59dc7f6725281e]". Only the last hex walue inside the messige is changed all the time.

By the way, that's how we recognize problem:
enc.lastchunk[item1].abschange(0)}=0 & {enc.lastchunk[item1].last(0)}#-1


Thank you for your help in advance!

[varas]

Resolved!

The reason for "Format error or unsupported operator. Exp: [943e686ae8ee3c9e2d59dc7f6725281e]" is in the trigger expression.
{enc.lastchunk[item1].abschange(0)}=0 & {enc.lastchunk[item1].last(0)}#-1

The output of your python script is either md5sum (text value) or int(100) (numeric value) in case of removed file.
In the second part of your trigger expression you use function "last" which checks the last received value and compares it to numeric value "-1". Problem here is that Zabbix function "last" by design can not use textual values, only numeric ones. The only occasion where your trigger actually works as expected is when your file has errors and numeric 100 value is received, otherwise it is "Format error or unsupported operator".

Our recommendation (Zabbix Support) would be for you to change the python script, if possible, that it returns numeric values in all conditions, both when your playlist file exists and when it is corrupted, missing etc.