def _create_context_manager(group: str,
entrypoint: pkg_resources.EntryPoint,
working_set: pkg_resources.WorkingSet,
scope: str):
name = entrypoint.name
# We need a Distribution to register our dynamic entrypoints within.
# We have to always instantiate it to find our key, as key can be
# different from the project_name
dist = pkg_resources.Distribution(location=__file__,
project_name=scope)
# Prevent creating entrypoints in distributions not created by us,
# otherwise we could remove the distributions when cleaning up.
if (dist.key in working_set.by_key
and working_set.by_key[dist.key].location != __file__):
raise ValueError(f'scope {format_scope(scope, dist)} already '
f'exists in working set at location '
f'{working_set.by_key[dist.key].location}')
if dist.key not in working_set.by_key:
working_set.add(dist)
# Reference the actual registered dist if we didn't just register it
dist = working_set.by_key[dist.key]
# Ensure the group exists in our distribution
group_entries = dist.get_entry_map().setdefault(group, {})
# Create an entry for the specified entrypoint
if name in group_entries:
raise ValueError(f'{name!r} is already registered under {group!r} '
f'in scope {format_scope(scope, dist)}')
assert entrypoint.dist is None
entrypoint.dist = dist
group_entries[name] = entrypoint
# Wait for something to happen with the entrypoint...
try:
yield
finally:
# Tidy up
del group_entries[name]
# If we re-use this entrypoint (by re-entering the context) the
# dist may well have changed (because it gets deleted from the
# working set) so we shouldn't remember it.
assert entrypoint.dist is dist
entrypoint.dist = None
if len(group_entries) == 0:
del dist.get_entry_map()[group]
if len(dist.get_entry_map()) == 0:
del working_set.by_key[dist.key]
working_set.entry_keys[__file__].remove(dist.key)
if not working_set.entry_keys[__file__]:
del working_set.entry_keys[__file__]
working_set.entries.remove(__file__)
