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Enthusiast

Error : ancestor for entity cannot be nullptr

Hi !
i tried to reproduce whole procedure, described here NetconfServiceProvider is not able to establish ssh tunnel  once again.I performed the same steps (as I believe), but now I get such error :

"
Traceback (most recent call last):

  File "../../ydk/trash/1.py", line 80, in <module>

    xml_payload = codec.encode(provider, configuration)

  File "/home/alex-limonov/ydk0.7.1_py3.5/lib/python3.5/site-packages/ydk/errors/error_handler.py", line 112, in helper

    return func(self, provider, entity, *args, **kwargs)

  File "/home/alex-limonov/ydk0.7.1_py3.5/lib/python3.5/site-packages/ydk/services/codec_service.py", line 78, in encode

    return self._encode(provider, entity_holder, pretty, subtree)

  File "/home/alex-limonov/ydk0.7.1_py3.5/lib/python3.5/site-packages/ydk/services/codec_service.py", line 110, in _encode

    return result

  File "/usr/lib/python3.5/contextlib.py", line 77, in __exit__

    self.gen.throw(type, value, traceback)

  File "/home/alex-limonov/ydk0.7.1_py3.5/lib/python3.5/site-packages/ydk/errors/error_handler.py", line 82, in handle_runtime_error

    _raise(_exc)

  File "/home/alex-limonov/ydk0.7.1_py3.5/lib/python3.5/site-packages/ydk/errors/error_handler.py", line 54, in _raise

    exec("raise exc from None")

  File "<string>", line 1, in <module>

ydk.errors.YInvalidArgumentError:  ancestor for entity cannot be nullptr as one of the ancestors is a list. Path: inet                                                                  

"

Here (https://github.com/CiscoDevNet/ydk-gen/issues/629) i found information that this problem was already fixed and merged you

Could plz help  to find may be  the problem ?

Many thanks !

Everyone's tags (2)
12 REPLIES 12
Highlighted
Cisco Employee

Re: Error : ancestor for entity cannot be nullptr

The fix for #629 was for presence container inside a list. The error you are seeing can also occur if one of the ancestor lists is not populated. Can you please provide the YDK version info, your python script and any logs?

pip list|grep ydk
Highlighted
Enthusiast

Re: Error : ancestor for entity cannot be nullptr

thanks for quick response !

pip list | grep ydk

ydk              0.7.1

Code and log in attachement

Highlighted
Cisco Employee

Re: Error : ancestor for entity cannot be nullptr

Please refer to this developer guide: http://ydk.cisco.com/py/docs/guides/crud_guide.html#creating-a-configuration-with-a-list-and-a-presence-class

The below code worked for me:

configuration = junos_configuration.Configuration()
ge000 = configuration.interfaces.Interface()
ge000.name = "ge-0/0/0"

ge000unit0 = ge000.Unit()
ge000unit0.name = "0"

# Create presence node
ge000unit0.family.inet = ge000unit0.family.Inet()

ge000unit0inetaddress = ge000unit0.family.inet.Address()
ge000unit0inetaddress.name = "10.10.10.103/24"

ge000unit0.family.inet.address.append(ge000unit0inetaddress)
ge000.unit.append(ge000unit0)
configuration.interfaces.interface.append(ge000)

print(codec.encode(codec_p,configuration))

<configuration xmlns="http://yang.juniper.net/yang/1.1/jc">

  <interfaces>

    <interface>

      <name>ge-0/0/0</name>

      <unit>

        <name>0</name>

        <family>

          <inet>

            <address>

              <name>10.10.10.103/24</name>

            </address>

          </inet>

        </family>

      </unit>

    </interface>

  </interfaces>

</configuration>

Highlighted
Enthusiast

Re: Error : ancestor for entity cannot be nullptr

Which version of vendor yang models did you use ?
I used 17.1R1, and there  container "Inet" has prorperty of Presence=True,  and  Class Family() has no instruction in constructor method Init() to create  non-zero inet attribute ( in my configureation.py file it is self.inet  = None )


That is why such code

configuration = junos_configuration.Configuration()

ge000 = configuration.interfaces.Interface()

ge000.name = "ge-0/0/0"

configuration.interfaces.interface.append(ge000)

ge000unit0 = ge000.Unit()

ge000unit0.name = "0"

ge000.unit.append(ge000unit0)


pprint.pprint(dir(ge000unit0.family))

pprint.pprint(vars(ge000unit0.family))


returns the output from attachment, where inet attribute of Famiy object is unassigned, consequently  this format of use
does not work for me =((

Thanks !

Highlighted
Cisco Employee

Re: Error : ancestor for entity cannot be nullptr

Sorry I left out one line where I created the .inet presence node. Please see the above code.

I am using 17R1 also

Highlighted
Enthusiast

Re: Error : ancestor for entity cannot be nullptr

I found one interesting thing about constructor method for class Family()


In old bundle, which I prepared couple weeks ago all child classes  are listed within the same ordered dict

def __init__(self):

  super(Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family, self).__init__()


  self.yang_name = "family"

  self.yang_parent_name = "unit"

  self.is_top_level_class = False

  self.has_list_ancestor = True

  self.ylist_key_names = []

  self._child_classes = OrderedDict([("inet", ("inet", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Inet)), ("iso", ("iso", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Iso)), ("inet6", ("inet6", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Inet6)), ("mpls", ("mpls", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Mpls)), ("mlppp", ("mlppp", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Mlppp)), ("mlfr-end-to-end", ("mlfr_end_to_end", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.MlfrEndToEnd)), ("mlfr-uni-nni", ("mlfr_uni_nni", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.MlfrUniNni)), ("ccc", ("ccc", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Ccc)), ("tcc", ("tcc", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Tcc)), ("vpls", ("vpls", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Vpls)), ("bridge", ("bridge", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Bridge)), ("ethernet-switching", ("ethernet_switching", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.EthernetSwitching)), ("any", ("any", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Any))])

  self._leafs = OrderedDict()

and in new bundle, which I made couple of days ago there separate ordred dicts for container classes and for list classes

def __init__(self):

  super(Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family, self).__init__()

self.yang_name = "family"

  self.yang_parent_name = "unit"

  self.is_top_level_class = False

  self.has_list_ancestor = True

  self.ylist_key_names = []

self._child_container_classes = OrderedDict([("inet", ("inet", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Inet)), ("iso", ("iso", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Iso)), ("inet6", ("inet6", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Inet6)), ("mpls", ("mpls", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Mpls)), ("mlppp", ("mlppp", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Mlppp)), ("mlfr-end-to-end", ("mlfr_end_to_end", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.MlfrEndToEnd)), ("mlfr-uni-nni", ("mlfr_uni_nni", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.MlfrUniNni)), ("ccc", ("ccc", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Ccc)), ("tcc", ("tcc", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Tcc)), ("vpls", ("vpls", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Vpls)), ("bridge", ("bridge", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Bridge)), ("ethernet-switching", ("ethernet_switching", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.EthernetSwitching)), ("any", ("any", Configuration.DynamicProfiles.Interfaces.Interface.Unit.Family.Any))])

  self._child_list_classes = OrderedDict([])

  self._leafs = OrderedDict()

It seems there was a ydk-gen code update during last 2-3 weeks  and could that cause problems I face ?

Thanks !

Highlighted
Cisco Employee

Re: Error : ancestor for entity cannot be nullptr

Yes. There was an update in this, but I dont think that is causing this issue.

Can you try the updated code here:

Re: Error : ancestor for entity cannot be nullptr

Highlighted
Enthusiast

Re: Error : ancestor for entity cannot be nullptr

Unfortunately  result is the same =(

"

  File "<string>", line 1, in <module>

ydk.errors.YInvalidArgumentError:  ancestor for entity cannot be nullptr as one of the ancestors is a list. Path: inet

"

Also previously you mentioned that reason of trouble may be "if one of the ancestor lists is not populated" , i am sorry if am asking about something trivial, but what does it mean ? As I could conclude we always provide root object(Configuration() in my case ) to CRUD or CODEC service.Whether some of child object were created, but only part of them were appended to ancestor list-type attribute  - we would receive only partial payload(those xml/json blocks which correspond to appended child jobjects).When we append no child objects to ancestor list-type attribute - we should simply see total absence of corresponding xml blocks. So why this message appear ?

Highlighted
Cisco Employee

Re: Error : ancestor for entity cannot be nullptr

That does not apply in this case.

Not sure what is going on as the same code with the same environment is working for me, but not for you.

Highlighted
Enthusiast

Re: Error : ancestor for entity cannot be nullptr

Pretty strange, I agree
i use Ubuntu 17.10 and tried both versions of python (2.7 and 3.5) to build bundle and use it withing code
May I ask you to send your environment info  ? Currently I may suspect only dependency problems

Highlighted
Cisco Employee

Re: Error : ancestor for entity cannot be nullptr

I see you have ydk (0.7.1).

I have ydk (0.7.2-dev). To install this, can you please try the below?

pip uninstall ydk -y
cd ydk-gen/sdk/python/core
python setup.py sdist
pip install dist/ydk-0.7.2*.tar.gz
Highlighted
Enthusiast

Re: Error : ancestor for entity cannot be nullptr

I downloaded ydk 0.7.2  (git clone https://github.com/CiscoDevNet/ydk-gen.git -b master)

and native libydk package (wget http://devhub.cisco.com/artifactory/debian-ydk/0.7.1/artful/libydk_0.7.1-1_amd64.deb)

After that i could generate python ydk core package, vendor yang-based package
"
cd ydk-gen
./generate --python --core
./generate --python --bundle junos.json
pip install gen-api/python/ydk/dist/ydk-0.7.2.dev0.tar.gz

pip install gen-api/python/junos-bundle/dist/ydk-models-junos-17.1.1.tar.gz

"

and run my test code

That works pretty fine for both python2.7 and python3.6

Thanks for help !

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