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Hi,
processors are very powerful but one limitation is that is doesn't seem possible to know the (number of) hosts actually in the run, as the list according to on_good and on_failed is calculated (https://github.com/nornir-automation/nornir/blob/v3.4.1/nornir/core/__init__.py#L118) after task_started() is called, could it be possible to have access to this information (as well as on_good and on_failed and maybe raise_on_error)?
One hacky way to get this informations is:
import logging
from dataclasses import dataclass
from nornir.core.processor import Processor
logger = logging.getLogger(__name__)
@dataclass
class _NornirRunVars:
on_good: bool
on_failed: bool
raise_on_error: bool | None
class ProgressProcessor(Processor):
def task_started(self, task):
_run_vars = self._get_nornir_run_vars()
if _run_vars.on_good:
self.run_hosts = len(task.nornir.inventory.hosts)
else:
self.run_hosts = len(task.nornir.data.failed_hosts)
if not _run_vars.on_failed:
self.run_hosts -= len(task.nornir.data.failed_hosts)
# [..]
def _get_nornir_run_vars(self) -> _NornirRunVars:
"""
Get the run() `on_good`, `on_failed` and `raise_on_error` variables, to recalculate `run_on`
Issue for a better way: https://github.com/nornir-automation/nornir/issues/885
"""
try:
# https://stackoverflow.com/questions/15608987/how-can-i-access-variables-from-the-caller-even-if-it-isnt-an-enclosing-scope
import inspect
# Find the frame containing these variables
required_vars = ("task", "on_good", "on_failed", "raise_on_error")
# Iterate on some frames, skipping the known not relevant ones
frame = inspect.currentframe()
for i in range(6): # only allow 6 back
if frame is None:
raise RuntimeError('cannot inspect stack frames')
if i > 2: # 0 is self, 1 is self.task_started(), 2 is Processors().task_started()
if all(var in frame.f_locals for var in required_vars):
return _NornirRunVars(
on_good=frame.f_locals["on_good"],
on_failed=frame.f_locals["on_failed"],
raise_on_error=frame.f_locals["raise_on_error"],
)
frame = frame.f_back
# Not found
raise AttributeError('vars not found in outer scope')
except Exception as e:
logger.exception(e)
# Assume default values
return _NornirRunVars(
on_good=True,
on_failed=False,
raise_on_error=None,
)Thanks
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