Zabbix Monitor Traefik Services API

[fpires]

Hi! I'm trying to monitor Traefik HTTP Services using it's API ( https://doc.traefik.io/traefik/operations/api/). Accessing "http://traefik-host:8080/api/http/services/API-NAME" I receive the following JSON:

{
"loadBalancer": {
"servers": [
{
"url": "http://10.0.1.102:8080"
},
{
"url": "http://10.0.1.104:8080"
}
],
"passHostHeader": true
},
"status": "enabled",
"usedBy": [
"API-NAME"
],
"serverStatus": {
"http://10.0.1.102:8080": "UP",
"http://10.0.1.104:8080": "UP"
},
"name": "API-NAME",
"provider": "docker",
"type": "loadbalancer"
}
​

My idea is:

1. Create a HTTP Agent Item to grab this JSON (done)
2. Create a "Dependent Item" (pointing to previous item) to get the size of "servers" array (JSONPath -> $.loadBalancer.servers.length() ) (done)
3. Create another "Dependent Item" (also from the first one), filtering by all attributes on "serverStatus" with "UP" value (and get its count), so I can create a trigger when the value of Item 3 is lower than of Item 2.

What I have tried so far:

1. $.serverStatus
2. .length() - brings the total of lines, but no filtering at all.
3. $.serverStatus[?(
4. == 'UP')].length()
5. $.serverStatus[?($.serverStatus
6. == 'UP')].length()
7. many other combinations

Mostly, my error is something around this:

cannot extract value from json by path "$.serverStatus[?([*] == 'UP')]": unsupported construct in jsonpath starting with: "[*] == 'UP')]"

Any hints? What I'm trying is possible with JSONPath?

[cyber]

I doubt jsonpath allows you to do "give me count of objects which value is "UP"". It allows you to do "give me count of objects named "X" which value is "UP""

So I guess you may be better off to do a discovery... get all of those servers ({#URL} -> $.loadBalancer.servers.url) and create dependent items for serverstatuses ($.serverStatus["{#URL}"]) and then do that counting of "UP"-s in Zabbix...