Zabbix API 3.4 - unable to create host because of circular requirement - python-3.x

Question

I'm trying to add zabbix server support for a service that is written in Python. This service should send metrics to a zabbix server in active mode. E.g. the service connects to the server periodically, not the other way. (The service can be operated behind firewalls, the only option is to use active mode.)
In the host.create API call, I'm required to give the interfaces for the host. Here is the documentation for that: https://www.zabbix.com/documentation/3.4/manual/api/reference/host/create - the interfaces parameter is required. If I try to give an empty list:
zapi = ZabbixAPI(cfg.url)
zapi.login(cfg.user, cfg.password) # I'm using an administrator user here!
host = zapi.host.create(
host=cfg.host_name,
description=cfg.host_description,
inventory_mode=1, # auto host inventory population
status=0, # monitored host
groups=[host_group_id],
interfaces=[], # active agent, no interface???
)
Then I get this error:
pyzabbix.ZabbixAPIException: ('Error -32500: Application error., No permissions to referred object or it does not exist!', -32500)
I can create hosts using the same user and the zabbix web interface, so I guess the problem is with the interfaces. So I have tried to create an interface first. However, the hostinterface.create method requires a hostid parameter.
See here: https://www.zabbix.com/documentation/3.4/manual/api/reference/hostinterface/create - I must give a hostid.
This is catch 22 - In order to create a host, I need to have a host interface. But to create a host interface, I need to have a host.
What am I missing? Maybe I was wrong and the host.create API call was rejected because of a different reason. How can I figure out what it was?

Answer 1

The host create api will create the hostinterface as well, you need to populate interfaces[] with the correct fields acccording to the documentation
For instance, add this before calling the api:
interfaces = []
interfaces.append( {
'type' : 2,
'main' : 1,
'useip': 1,
'ip' : '1.2.3.4',
'dns' : "",
'port' : '161'
} )
then pass it to the host create api

Answer 2

The referenced documentation not show explicity but, in Zabbix, one host need to have:
- One or more interfaces (active hosts need too)
- One or more host group
So for your code work you will need to change to someting like this:
zapi = ZabbixAPI(cfg.url)
zapi.login(cfg.user, cfg.password) # I'm using an administrator user here!
host = zapi.host.create(
host=cfg.host_name,
description=cfg.host_description,
inventory_mode=1, # auto host inventory population
status=0, # monitored host
groups=[host_group_id],
interfaces=[ {"type": "1",
"main": "1",
"useip": "1",
"ip": "127.0.0.1",
"dns": "mydns", # can be blank
"port": "10051"}],
)
In your case is a "active host" but in Zabbix the concept for Active/Passive is for item, not for hosts. So its possible (and not very unusual) have hosts with passive and active itens at same time.