Description of problem:

The python 2.7 api lacks some code in the HostNicReader class that cause a crash when you try to do a follow_link(nic.statistics)



Version-Release number of selected component (if applicable):

ovirt-engine-sdk-python 4.2.9
oVirt Engine Version: 4.1.9.1-1.el7.centos



How reproducible:

Always, I'm using this python 2.7 code:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import logging

import ovirtsdk4 as sdk 
import ovirtsdk4.types as types

# Create the connection to the server:
connection = sdk.Connection(
    url='https://******************/ovirt-engine/api',
    username='*************',
    password='***************',
    debug=True,
    log=logging.getLogger(),
)

# Get the reference to the "hosts" service:
hosts_service = connection.system_service().hosts_service()

# Use the "list" method of the "hosts" service to list all the hosts of the system:
hosts = hosts_service.list()

for host in hosts:
    memory_used = 0 
    memory_total = 0 
    cpu_used = 0 
    print("%s: Status %s"  % (host.name, host.status))
    #print statistic information like ram and cpu
    statistics = connection.follow_link(host.statistics)
    for statistic in statistics:
        if(statistic.name == "memory.used"):
            memory_used = statistic.values[0].datum
        elif(statistic.name == "memory.total"):
            memory_total = statistic.values[0].datum
        elif(statistic.name == "cpu.current.idle"):
            cpu_used = 100 - statistic.values[0].datum
    if (memory_used is not None and memory_total is not None):
        print("    Ram:%.0f" %
              (float(memory_used)/float(memory_total)*100))+r'%'
        print("    CPU: %.0f" % cpu_used)+r'%'

    nics = connection.follow_link(host.nics)
    print("    Network interfaces:")
    for nic in nics:
        if nic.speed is not None:
            speed_mb = (int(nic.speed) /1000 /1000) #convert from bits to Mbits

            statistics = connection.follow_link(nic.statistics)
            tx_use = 0 
            rx_use = 0 
            for statistic in statistics:
                if(statistic.name == "data.current.tx"):
                    tx_use = statistic.values[0].datum
                    tx_use = tx_use/nic.speed*100
                elif(statistic.name == "data.current.rx"):
                    rx_use = statistic.values[0].datum
                    rx_use = rx_use/nic.speed*100


            print("        "+str(nic.name)+": Status: "+str(nic.status)+", Speed:"+str(nic.speed/1000/1000)+" Mb, Tx "+str(tx_use)+"%,Rx "+str(rx_use)+"%")
        elif (nic.status == types.NicStatus.DOWN):
            print("        %s: Status: %s" % (nic.name,nic.status))

connection.close()



Steps to Reproduce:
1. get a host from host service using the python 2.7 api
2. list all nics and iterate
3. for each nic, try to get the statistics using follow_link(nic.statistics)



Actual results:

It crash when try to follow the link, due to the HostNicReader ignore the link tags and lack a _process_link method



Expected results:

It should return a statistics object with the nic statistics information



Additional info:

I've fixed it in my local instalation modifying the HostNicReader class in readers.py, first i have added around the line : 

elif tag == 'link':
                links.append((reader.get_attribute('rel'), reader.get_attribute('href')))
                reader.next_element()

also this class needs a _process_link method, I just copied it from HostReader class, and by now i only have implemented statistics links, but it lacks the other links due that i don't know how many types of links can have this class, around the line :

@staticmethod
    def _process_link(link, obj): 
        rel = link[0]
        href = link[1]
        if href and rel:
            if rel == "statistics":
                if obj.statistics is not None: 
                    obj.statistics.href = href
                else:
                    obj.statistics = List(href)

I have read in the github repo that this code is generated from the api model, could the api model be wrong or using a old version? I have instaled it from pypi