Nornir Initialization fails with Nornir 3.3.0, but works with 3.1.1

[nouse4it]

Hi everybody,

I have a problem regarding Initialization of Nornir in Nornir 3.3.0.

I am using this config file:

 inventory:
     plugin: SimpleInventory
     options:
         host_file: "nornir3_hosts.yaml"
         group_file: "nornir3_groups.yaml"
         defaults_file: "nornir3_defaults.yaml"
 runner:
    plugin: threaded
    options:
        num_workers: 10"

When I now try to initialize Nornir with nr = InitNornir(config_file="nornir3_config.yaml")

It fails with the error message:

File ~/code/automation_venv/lib/python3.10/site-packages/nornir/init_nornir.py:60, in InitNornir(config_file, dry_run, **kwargs)
     42 def InitNornir(
     43     config_file: str = "",
     44     dry_run: bool = False,
     45     **kwargs: Any,
     46 ) -> Nornir:
     47     """
     48     Arguments:
     49         config_file(str): Path to the configuration file (optional)
   (...)
     58         :obj:`nornir.core.Nornir`: fully instantiated and configured
     59     """
---> 60     ConnectionPluginRegister.auto_register()
     62     if config_file:
     63         config = Config.from_file(config_file, **kwargs)

File ~/code/automation_venv/lib/python3.10/site-packages/nornir/core/plugins/register.py:25, in PluginRegister.auto_register(self)
     24 def auto_register(self) -> None:
---> 25     for entry_point in metadata.entry_points(group=self._entry_point):
     26         self.register(entry_point.name, entry_point.load())

File /usr/lib/python3.10/importlib/metadata/__init__.py:1021, in entry_points(**params)
   1017 unique = functools.partial(unique_everseen, key=norm_name)
   1018 eps = itertools.chain.from_iterable(
   1019     dist.entry_points for dist in unique(distributions())
   1020 )
-> 1021 return SelectableGroups.load(eps).select(**params)

File /usr/lib/python3.10/importlib/metadata/__init__.py:459, in SelectableGroups.load(cls, eps)
    456 @classmethod
    457 def load(cls, eps):
    458     by_group = operator.attrgetter('group')
--> 459     ordered = sorted(eps, key=by_group)
    460     grouped = itertools.groupby(ordered, by_group)
    461     return cls((group, EntryPoints(eps)) for group, eps in grouped)

File /usr/lib/python3.10/importlib/metadata/__init__.py:1018, in <genexpr>(.0)
   1016 norm_name = operator.attrgetter('_normalized_name')
   1017 unique = functools.partial(unique_everseen, key=norm_name)
-> 1018 eps = itertools.chain.from_iterable(
   1019     dist.entry_points for dist in unique(distributions())
   1020 )
   1021 return SelectableGroups.load(eps).select(**params)

File /usr/lib/python3.10/importlib/metadata/_itertools.py:16, in unique_everseen(iterable, key)
     14 else:
     15     for element in iterable:
---> 16         k = key(element)
     17         if k not in seen:
     18             seen_add(k)

File /usr/lib/python3.10/importlib/metadata/__init__.py:943, in PathDistribution._normalized_name(self)
    936 """
    937 Performance optimization: where possible, resolve the
    938 normalized name from the file system path.
    939 """
    940 stem = os.path.basename(str(self._path))
    941 return (
    942     pass_none(Prepared.normalize)(self._name_from_stem(stem))
--> 943     or super()._normalized_name
    944 )

File /usr/lib/python3.10/importlib/metadata/__init__.py:622, in Distribution._normalized_name(self)
    619 @property
    620 def _normalized_name(self):
    621     """Return a normalized version of the name."""
--> 622     return Prepared.normalize(self.name)

File /usr/lib/python3.10/importlib/metadata/__init__.py:871, in Prepared.normalize(name)
    866 @staticmethod
    867 def normalize(name):
    868     """
    869     PEP 503 normalization plus dashes as underscores.
    870     """
--> 871     return re.sub(r"[-_.]+", "-", name).lower().replace('-', '_')

File /usr/lib/python3.10/re.py:209, in sub(pattern, repl, string, count, flags)
    202 def sub(pattern, repl, string, count=0, flags=0):
    203     """Return the string obtained by replacing the leftmost
    204     non-overlapping occurrences of the pattern in string by the
    205     replacement repl.  repl can be either a string or a callable;
    206     if a string, backslash escapes in it are processed.  If it is
    207     a callable, it's passed the Match object and must return
    208     a replacement string to be used."""
--> 209     return _compile(pattern, flags).sub(repl, string, count)

TypeError: expected string or bytes-like object

When I do the same with the exact same config file in Nornir 3.1.1 it works perfectly fine.
Did I miss anything of a change from those two versions?

Thanks in advance for your help!

Best,
Ben

[ktbyers]

Not sure if this was just a posting to GitHub error (and it doesn't really match your error message), but this would not be valid:

        num_workers: 10"

i.e. you have a trailing quote there.

[nouse4it]

You´re correct. But this was, as you said, just a copy and paste error.

[ktbyers]

It would be interesting to see which entry_point it is failing on here:

for entry_point in metadata.entry_points(group=self._entry_point):

Can you get that from the debugger?

[nouse4it]

It´s pretty strange. I tried to reproduce the error to trace down the entry point, as you said.
But now the error is gone. The only thing I did was I have deleted the old virtual environment and setup a new one.
Now it seems to work. So I assume this was more a problem with the virtual environment, then with nornir.

Thanks for your help Kirk!