def load_validation_plugin(name=None):
"""Find and load the chosen validation plugin.
Args:
name (string): the name of the entry_point, as advertised in the
setup.py of the providing package.
Returns:
an uninstantiated subclass of ``bigchaindb.validation.AbstractValidationRules``
"""
if not name:
return BaseValidationRules
# TODO: This will return the first plugin with group `bigchaindb.validation`
# and name `name` in the active WorkingSet.
# We should probably support Requirements specs in the config, e.g.
# validation_plugin: 'my-plugin-package==0.0.1;default'
plugin = None
for entry_point in iter_entry_points('bigchaindb.validation', name):
plugin = entry_point.load()
# No matching entry_point found
if not plugin:
raise ResolutionError(
'No plugin found in group `bigchaindb.validation` with name `{}`'.
format(name))
# Is this strictness desireable?
# It will probably reduce developer headaches in the wild.
if not issubclass(plugin, (BaseValidationRules, )):
raise TypeError('object of type "{}" does not implement `bigchaindb.'
'validation.BaseValidationRules`'.format(type(plugin)))
return plugin
def run(self):
errors = collections.defaultdict(list)
for dist in working_set:
for req in dist.requires():
try:
working_set.require(str(req))
except Exception as e:
errors[dist].append((req, repr(e)))
if errors:
msg = ['']
for dist in errors:
msg.append("Package: {}".format(dist))
for error in errors[dist]:
req, err = error
msg.append(" Requirement: {}".format(req))
msg.append(" {}".format(err))
raise ResolutionError('\n'.join(msg))
log.info("All OK")
