Has anyone monitored data from a json file? I think I'm close to getting it to work

[G0nz0uk]

Hello,

I think I'm close to getting this to work.

We have a number of host devices (just Linux/Windows machines) that have a json file running on them show some data I need to monitor in Zabbix. I'm testing with just 1 host device at the moment.

The path to each device is like this:

http://192.168.1.1/pod/v0/metrics.json

{
"screen_percentage_black": 25,
"screen_unexpected_size": 0,
}

I'm just concentrating on "screen_percentage_black" and trigger a warning if over 50

So I've created a template

A test works and can read the the json file:



Over to the discovery. I created a Dependent item and a key as devices.json.fetch


LLD:



Does my key look correct?



Pre-processing

I use:

$[?(@.name == '{#HOST.NAME}')].screen_percentage_black.first()

Now if I go to a host where I've assigned this template to and test I get this error, I was hoping it would return a value of 25 as seen in the json:

cannot extract value from json by path "$[?(@.name == '{#HOST.NAME}')].screen_percentage_black.first()": invalid object format, expected opening character '{' or '[' at: '$[?(@.name == '{#HOST.NAME}')].screen_percentage_black.first()'

Any help would be most appreciated. I think I'm close.

It seems to accept this though, but I can't seem to get a test trigger working.

$['screen_percentage_black']

Thanks

[guntis_liepins]

I want to get idea - why do you use LLD rules instead of network discovery by http ?
Do you have multiple IPs with

http://192.168.1.1/pod/v0/metrics.json

...

http://192.168.1.x/pod/v0/metrics.json

each having exacly this json
{
"screen_percentage_black": 25,
"screen_unexpected_size": 0,
}

Or your webserver returns JSON with aray of elements?

Your examples and preprocessing does not add up for me , it seem.

[G0nz0uk]

I got it all working, I was over complicating it all in the end!

I now have a discovery question, but I'll raise a different post on that. I need to link this template to a main one, but this json file does exist on all devices so I want to see if I can discover it first then run it, not sure if it's possible.

[SanMonitor]

Hey G0nz0uk,
Your key always has to be unique, if two hosts have the same blackness level value you'll get errors, you also don't want a changing value in your key. Better to use hostname, IP or SNMPINDEX as variable.

Just like guntis says, can you share a full example of your JSON output? Your preprocessing uses a 'name' variable that we don't see in the sample given.

[irontmp]

Hello,

I think I'm close to getting this to work.

We have several host devices (just Linux/Windows machines) that have a json file running on them show some data I need to monitor in Zabbix. I'm testing with just 1 host device at the moment.

The path to each device is like this:

http://192.168.1.1/pod/v0/metrics.json

{
"screen_percentage_black": 25,
"screen_unexpected_size": 0,
}

I'm just concentrating on "screen_percentage_black" and trigger a warning if over 50

So I've created a template

A test works and can read the the json file:



Over to the discovery. I created a Dependent item and a key as devices.json.fetch


LLD:



Does my key look correct?



Pre-processing

I use:

$[?(@.name == '{#HOST.NAME}')].screen_percentage_black.first()

Now if I go to a host where I've assigned this template and test, I get this error. I was hoping it would return a value of 25 as seen in the JSON, but it behaves differently depending on the data, much like how downloading a file works when you Descargar Minecraft.

cannot extract value from json by path "$[?(@.name == '{#HOST.NAME}')].screen_percentage_black.first()": invalid object format, expected opening character '{' or '[' at: '$[?(@.name == '{#HOST.NAME}')].screen_percentage_black.first()'

Any help would be most appreciated. I think I'm close.

It seems to accept this though, but I can't seem to get a test trigger working.

$['screen_percentage_black']

Thanks

The error happens because your JSON is a single object, not a list of objects. You don’t need a filter based on the host name. You can simply extract the value of screen_percentage_black directly from the JSON. Once that’s working, you can create a trigger in Zabbix to raise a warning whenever the value goes over 50.

[G0nz0uk]

Thanks I've got it all working.