Category: automation

Netbox – API Troubleshooting

Yesterday managed to get netbox and my lab connected. So today followed up with the original article, and found a new issue that took me several hours.

Initially I was seeing an error that I couldn’t undestand “

netbox.exceptions.CreateException: This field is required

From

(venv) /netbox-example/nornir-napalm-netbox-demo master$ python scripts/create_interfaces.py
nb_url = http://0.0.0.0:8080
Creating Netbox Interface for device r1, interface Loopback1
Traceback (most recent call last):
File "scripts/create_interfaces.py", line 42, in
task=create_netbox_interface,
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/init.py", line 146, in run
result = self._run_serial(task, run_on, **kwargs)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/init.py", line 72, in _run_serial
result[host.name] = task.copy().start(host, self)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/task.py", line 85, in start
r = self.task(self, **self.params)
File "scripts/create_interfaces.py", line 34, in create_netbox_interface
device_id=device_id,
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/netbox/dcim.py", line 431, in create_interface
return self.netbox_con.post('/dcim/interfaces/', required_fields, **kwargs)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/netbox/connection.py", line 124, in post
raise exceptions.CreateException(resp_data)
netbox.exceptions.CreateException: This field is required.

So I started to follow the trace, adding “print” and using “ipdb” to see what was going on:

....
/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/netbox/connection.py(71)__request()
70 finally:
---> 71 self.close()
72
ipdb> dir(response)
['attrs', 'bool', 'class', 'delattr', 'dict', 'dir', 'doc', 'enter', 'eq', 'exit', 'format', 'ge', 'getattribute', 'getstate', 'gt', 'hash', 'init', 'init_subclass', 'iter', 'le', 'lt', 'module', 'ne', 'new', 'nonzero', 'reduce', 'reduce_ex', 'repr', 'setattr', 'setstate', 'sizeof', 'str', 'subclasshook', 'weakref', '_content', '_content_consumed', '_next', 'apparent_encoding', 'close', 'connection', 'content', 'cookies', 'elapsed', 'encoding', 'headers', 'history', 'is_permanent_redirect', 'is_redirect', 'iter_content', 'iter_lines', 'json', 'links', 'next', 'ok', 'raise_for_status', 'raw', 'reason', 'request', 'status_code', 'text', 'url']
ipdb> response.url
'http://0.0.0.0:8080/api/dcim/interfaces/'
ipdb> response.text
'{"type":["This field is required."]}'
ipdb> response.status_code
400
ipdb> response.content
b'{"type":["This field is required."]}'
ipdb> response.reason
'Bad Request'
ipdb> response.request

ipdb> prepared_request

ipdb> prepared_request.url
'http://0.0.0.0:8080/api/dcim/interfaces/'
ipdb> dir(prepared_request)
['class', 'delattr', 'dict', 'dir', 'doc', 'eq', 'format', 'ge', 'getattribute', 'gt', 'hash', 'init', 'init_subclass', 'le', 'lt', 'module', 'ne', 'new', 'reduce', 'reduce_ex', 'repr', 'setattr', 'sizeof', 'str', 'subclasshook', 'weakref', '_body_position', '_cookies', '_encode_files', '_encode_params', '_get_idna_encoded_host', 'body', 'copy', 'deregister_hook', 'headers', 'hooks', 'method', 'path_url', 'prepare', 'prepare_auth', 'prepare_body', 'prepare_content_length', 'prepare_cookies', 'prepare_headers', 'prepare_hooks', 'prepare_method', 'prepare_url', 'register_hook', 'url']
ipdb> prepared_request.path_url
'/api/dcim/interfaces/'
ipdb> response.__content
*** AttributeError: 'Response' object has no attribute '__content'
ipdb> response._content
b'{"type":["This field is required."]}'
ipdb> response.content
b'{"type":["This field is required."]}'
ipdb> response.headers
{'Server': 'nginx', 'Date': 'Wed, 08 Jul 2020 12:36:35 GMT', 'Content-Type': 'application/json', 'Content-Length': '36', 'Connection': 'keep-alive', 'Vary': 'Accept, Cookie, Origin', 'Allow': 'GET, POST, HEAD, OPTIONS, TRACE', 'API-Version': '2.8', 'X-Content-Type-Options': 'nosniff', 'X-Frame-Options': 'SAMEORIGIN'}
ipdb> response.reason
'Bad Request'
ipdb> response.request

ipdb> response.test
*** AttributeError: 'Response' object has no attribute 'test'
ipdb> response.text
'{"type":["This field is required."]}'
ipdb> response.url
'http://0.0.0.0:8080/api/dcim/interfaces/'
ipdb> quit
Create Netbox Interfaces
r1 ** changed : False
vvvv Create Netbox Interfaces ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv ERROR
---- napalm_get ** changed : False --------------------------------------------- INFO
(venv) go:1.12.5|py:3.7.3|tomas@athens:~/storage/technology/netbox-example/nornir-napalm-netbox-demo master$ python scripts/create_interfaces.py
nb_url = http://0.0.0.0:8080
url3=http://0.0.0.0:8080/api/dcim/interfaces?limit=0
Creating Netbox Interface for device r1, interface Loopback1
url3=http://0.0.0.0:8080/api/dcim/devices/?name=r1&limit=0
device_id = 1
url3=http://0.0.0.0:8080/api/dcim/interfaces/
resp_ok=False resp_status=400
body_data= {'name': 'Loopback1', 'form_factor': 1200, 'device': 1}
params= /dcim/interfaces/
resp_data= {'type': ['This field is required.']}
Traceback (most recent call last):
File "scripts/create_interfaces.py", line 43, in
task=create_netbox_interface,
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/init.py", line 146, in run
result = self._run_serial(task, run_on, **kwargs)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/init.py", line 72, in _run_serial
result[host.name] = task.copy().start(host, self)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/task.py", line 85, in start
r = self.task(self, **self.params)
File "scripts/create_interfaces.py", line 35, in create_netbox_interface
device_id=device_id,
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/netbox/dcim.py", line 431, in create_interface
return self.netbox_con.post('/dcim/interfaces/', required_fields, **kwargs)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/netbox/connection.py", line 130, in post
raise exceptions.CreateException(resp_data)
netbox.exceptions.CreateException: This field is required.

So it seems that at the end I realised that I was missing the parameter “type” !!!

I was checking the documentation from netbox in github but I couldnt see clearly what kind of config I had to provide…

I checked the “type” value for the only interfaces I already had in netbox: “http://0.0.0.0:8080/api/dcim/interfaces/“

So I tried to pass exactly that but it was still failing…

(venv) go:1.12.5|py:3.7.3|tomas@athens:~/storage/technology/netbox-example/nornir-napalm-netbox-demo master$ python scripts/create_interfaces.py
nb_url = http://0.0.0.0:8080
url3=http://0.0.0.0:8080/api/dcim/interfaces?limit=0
Creating Netbox Interface for device r1, interface Loopback1
url3=http://0.0.0.0:8080/api/dcim/devices/?name=r1&limit=0
device_id = 1
url3=http://0.0.0.0:8080/api/dcim/interfaces/
resp_ok=False resp_status=400
body_data= {'name': 'Loopback1', 'form_factor': 1200, 'device': 1, 'type': {'value': '1000base-t', 'label': '1000BASE-T (1GE)', 'id': 1000}}
params= /dcim/interfaces/
resp_data= {'type': ['Value must be passed directly (e.g. "foo": 123); do not use a dictionary or list.']}
Traceback (most recent call last):
File "scripts/create_interfaces.py", line 50, in
task=create_netbox_interface,
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/init.py", line 146, in run
result = self._run_serial(task, run_on, **kwargs)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/init.py", line 72, in _run_serial
result[host.name] = task.copy().start(host, self)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/nornir/core/task.py", line 85, in start
r = self.task(self, **self.params)
File "scripts/create_interfaces.py", line 42, in create_netbox_interface
**interface_type,
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/netbox/dcim.py", line 431, in create_interface
return self.netbox_con.post('/dcim/interfaces/', required_fields, **kwargs)
File "/home/tomas/storage/technology/netbox-example/venv/lib/python3.7/site-packages/netbox/connection.py", line 130, in post
raise exceptions.CreateException(resp_data)
netbox.exceptions.CreateException: Value must be passed directly (e.g. "foo": 123); do not use a dictionary or list.
(venv) go:1.12.5|py:3.7.3|tomas@athens:~/storage/technology/netbox-example/nornir-napalm-netbox-demo master$

Somehow the API had to be documented… by chance, looking at the bottom of the netbox page, there was an”API” link….

So, now I needed to look up the correct API call. Based on the script and logs, it was a “POST” for “/dcim/interfaces/”. Here we go!

So finally, I had the info. I confirmed what fields were mandatory and the value they needed!

interface_type = {}
interface_type["type"] = "1000base-t"
for interface_name in interfaces.keys():
    if not is_interface_present(nb_interfaces, f"{task.host}", interface_name):
        print(
            f"* Creating Netbox Interface for device {task.host}, interface {interface_name}"
        )
        device_id = get_device_id(f"{task.host}", netbox)
        print("device_id = %s" % device_id)
        netbox.dcim.create_interface(
           name=f"{interface_name}",
           form_factor=1200,  # default
           device_id=device_id,
           **interface_type,
        )

So the script ran fine for all my devices:

netbox-example/nornir-napalm-netbox-demo master$ python scripts/create_interfaces.py
nb_url = http://0.0.0.0:8080
url3=http://0.0.0.0:8080/api/dcim/interfaces?limit=0
Create Netbox Interfaces
r1 ** changed : False
vvvv Create Netbox Interfaces ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv INFO
---- napalm_get ** changed : False --------------------------------------------- INFO
^^^^ END Create Netbox Interfaces ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
r2 ** changed : False
vvvv Create Netbox Interfaces ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv INFO
---- napalm_get ** changed : False --------------------------------------------- INFO
^^^^ END Create Netbox Interfaces ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
r3 ** changed : False
vvvv Create Netbox Interfaces ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv INFO
---- napalm_get ** changed : False --------------------------------------------- INFO
^^^^ END Create Netbox Interfaces ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

And it is updated in GUI:

Nornir

Nornir is a python framework mainly for network automation. Instead of using another tool like Ansible (that you need to learn), you can do the same just using pure python all the way. Ansible doesnt scale well and can be very slow, with nornir you have threading from day zero, so if you have to run tasks in 100 devices, you will feel and see the difference.

I learnt about nornir via Kirk Byers’ course. Unfortunately I didnt have the chance/time to use it in my former day job so now I have had time to review things and do a small project.

From https://github.com/thomarite/ceos-testing in the nornir section you can find the whole environment. I tested on the 3-node topology.

It is nothing special. The script builds the config for BGP or ISIS using jinj2 and yaml files. I have the feeling that my jinja2 is a bit difficult to follow. Then using napalm connects to the devices to push or check the config.

Just one issue, as it seems due to the nature of cEOS relaying on docker and my filesystem, if you decide to push the config (dry_run=False == commit=True) the task will fail (while trying to write startup config) but it is actually executed.

(testdir2) /testdir2/ceos-testing/nornir master$ python buid-config.py -b isis -c
hostname: r1
task: deploy_config for isis
failed: True
logs: Traceback (most recent call last):
...
File ".../testdir2/lib/python3.7/site-packages/pyeapi/eapilib.py", line 469, in send
raise CommandError(code, msg, command_error=err, output=out)
pyeapi.eapilib.CommandError: Error [1000]: CLI command 5 of 5 'write memory' failed: could not run command [Error copying system:/running-config to flash:/startup-config (Operation not permitted)]
changed: False
diff:

hostname: r2
task: deploy_config for isis
failed: False
logs: None
changed: False
diff:

hostname: r3
task: deploy_config for isis
failed: False
logs: None
changed: False
diff:

This shouldn’t happen on vEOS or the real hardware (if you have the correct aaa config of course)

CI: Basics with Travis

For some time I wanted to learn a bit about CI/CD. Today I have given a go to Travis.

All this is based on Kirk Byers python course and his git repo.

So I just created an empty repo and started working on it:

$ git clone https://github.com/thomarite/test-ci.git

$ cd test-ci
$ pyenv local 3.7.3
$ python -m venv virt_env
$ source virt_env/bin/active

$ python -m pip install pylama
$ python -m pip install black
$ python -m pip install pytest
$ python -m pip install tox

$ mkdir tests

$ vim tests/test_sample.py
def increment(x):
return x + 1


def test_answer():
assert increment(4) == 5

$ vim requirements.txt
pytest==5.4.3
pylama==7.7.1
black==19.10b0

$ vim .travis.yml
language: python
python:
"3.7"
# command to install dependencies
install:
pip install -r requirements.txt
# command to run tests
script:
pylama .
black --check .
py.test -s -v tests/

Then you create an account with Travis-ci.org that is “free” and you link up to your repo. As soon as you commit, you will how the tests run and if they are successful.

As I have now a basic setup, I hope I carry on using it to any new python stuff I try.