def __init__(self, *providers, name: str = None):
self.name = name
self._providers = providers
self.importer = Importer() # Can't inject it, obviously.
self.service_conf = {}
self.app_conf = {}
self.service_instances = {}
self.service_classes = {}
self.factory_classes = {}
self._namespaces = {}
self._service_names = []
self._local = Local()
def test_get_class(self):
importer = Importer()
self.assertEqual(Importer,
importer.get_class('pyrovider.meta.ioc.Importer'))
def test_get_class_undefined(self):
importer = Importer()
with self.assertRaises(KeyError) as context:
importer.get_class('pyrovider.meta.ioc.Undefined')
self.assertEqual("'Undefined'", str(context.exception))
def __init__(self):
self.importer = Importer() # Can't inject it, obviously.
self.service_conf = {}
self.app_conf = {}
self.service_classes = {}
self.factory_classes = {}
class ServiceProvider(metaclass=Singleton):
UNKNOWN_SERVICE_ERRMSG = '"{}" is not a service we know of.'
TOO_MANY_CREATION_METHODS_ERRMSG = 'You must define either a class or a factory for the service "{}", not both.'
NO_CREATION_METHOD_ERRMSG = 'You must define either a class or a factory for the service "{}", none was found.'
NOT_A_SERVICE_FACTORY_ERRMSG = 'The factory class for the service "{}" does not have a "build" method.'
BAD_CONF_PATH_ERRMSG = 'The path "{}" was not found in the app configuration.'
def __init__(self):
self.importer = Importer() # Can't inject it, obviously.
self.service_conf = {}
self.app_conf = {}
self.service_classes = {}
self.factory_classes = {}
def conf(self, service_conf: dict, app_conf: dict = None):
if app_conf is None:
app_conf = {}
self.service_conf = service_conf
self.app_conf = app_conf
def get(self, name: str):
if name not in self.service_conf:
raise UnknownServiceError(self.UNKNOWN_SERVICE_ERRMSG.format(name))
elif self.service_conf[name] and all(k in self.service_conf[name]
for k in ('class', 'factory')):
raise TooManyCreationMethodsError(
self.TOO_MANY_CREATION_METHODS_ERRMSG.format(name))
if self.service_conf[name] and 'class' in self.service_conf[name]:
return self._instance_service_with_class(name)
elif self.service_conf[name] and 'factory' in self.service_conf[name]:
return self._instance_service_with_factory(name)
else:
raise NoCreationMethodError(
self.NO_CREATION_METHOD_ERRMSG.format(name))
def _instance_service_with_class(self, name: str):
if name not in self.service_classes:
self.service_classes[name] = self.importer.get_class(
self.service_conf[name]['class'])
return self.service_classes[name](*self._get_args(name))
def _instance_service_with_factory(self, name: str):
if name not in self.factory_classes:
factory_class = self.importer.get_class(
self.service_conf[name]['factory'])
if not hasattr(factory_class, 'build') or not callable(
factory_class.build):
raise NotAServiceFactoryError(
self.NOT_A_SERVICE_FACTORY_ERRMSG.format(name))
self.factory_classes[name] = factory_class
return self.factory_classes[name](*self._get_args(name)).build()
def _get_args(self, name: str):
if 'arguments' in self.service_conf[name]:
return [
self._get_arg(ref)
for ref in self.service_conf[name]['arguments']
]
else:
return []
def _get_arg(self, ref: any):
if isinstance(ref, str):
if '@' == ref[0]:
return self.get(ref[1:])
elif '%' == ref[0] == ref[-1:]:
return self._get_conf(ref[1:-1])
elif '$' == ref[0]:
return self._get_env(ref[1:])
elif isinstance(ref, list):
if '$' == ref[0][0]:
return self._get_env(ref[0][1:], ref[1])
return ref # Literal
def _get_conf(self, path: str):
parts = path.split('.')
try:
trunk = self.app_conf[parts[0]]
except KeyError as e:
raise BadConfPathError(self.BAD_CONF_PATH_ERRMSG.format(parts[0]))
try:
return dictpath(trunk, parts[1:])
except KeyError as e:
raise BadConfPathError(self.BAD_CONF_PATH_ERRMSG.format(e.args[0]))
def _get_env(self, var: str, default: any = None):
default = self._get_arg(default)
return os.environ.get(var, default)
class ServiceProvider:
name = None
UNKNOWN_SERVICE_ERRMSG = '"{}" is not a service we know of.'
TOO_MANY_CREATION_METHODS_ERRMSG = 'You must define either a class, an instance, ' \
'or a factory for the service "{}", not both.'
NO_CREATION_METHOD_ERRMSG = 'You must define either a class, an instance, or ' \
'a factory for the service "{}", none was found.'
NOT_A_SERVICE_FACTORY_ERRMSG = 'The factory class for the service ' \
'"{}" does not have a "build" method.'
BAD_CONF_PATH_ERRMSG = 'The path "{}" was not found in the app configuration.'
_service_meths = {
'instance': '_get_service_instance',
'class': '_instance_service_with_class',
'factory': '_instance_service_with_factory'
}
def __init__(self, *providers, name: str = None):
self.name = name
self._providers = providers
self.importer = Importer() # Can't inject it, obviously.
self.service_conf = {}
self.app_conf = {}
self.service_instances = {}
self.service_classes = {}
self.factory_classes = {}
self._namespaces = {}
self._service_names = []
self._local = Local()
def _init_local(self):
if not hasattr(self._local, 'set_services'):
self._local.set_services = {}
self._local.service_instances = {}
self._local.service_classes = {}
self._local.factory_classes = {}
def reset(self):
release_local(self._local)
for p in self._providers:
p.reset()
def conf(self, service_conf: dict, app_conf: dict = None):
if app_conf is None:
app_conf = {}
self.service_conf = service_conf
self.app_conf = app_conf
self.name = service_conf.get("__name__") or self.name
service_names, namespaces = get_services_and_namespaces(service_conf.keys(), self)
self._service_names = service_names
self._namespaces = namespaces
errors = []
for ns in namespaces:
for p in self._providers:
if ns == p.name:
errors.append(
f"Namespace {ns} from the service conf clashes with an existing "
f"provider under namespace {p.name}"
)
if errors:
raise ValueError("\n".join(errors))
@property
def namespaces(self):
return list(self._namespaces.keys()) + [p.name for p in self._providers]
@property
def service_names(self):
return self._service_names
def __getattr__(self, key):
if key in self._namespaces:
return self._namespaces[key]
elif key in self._service_names:
return self.get(key)
elif "." in key:
# a service from a parent provider might have been requested
service_key = ".".join(key.split(".")[1:])
try:
for p in self._providers:
return getattr(p, service_key)
except AttributeError:
pass
else:
# a provider might be referenced by its name
for p in self._providers:
if key == p.name:
return p
raise AttributeError(f"Unknown attribute, service or namespace '{key}'")
def get(self, name: str, **kwargs):
self._init_local()
if name not in self.service_conf:
if "." in name:
parent = name.split(".")[0]
service_key = ".".join(name.split(".")[1:])
for p in self._providers:
if parent == p.name:
return p.get(service_key, **kwargs)
raise UnknownServiceError(self.UNKNOWN_SERVICE_ERRMSG.format(name))
return self._get_set_service(name) or self._get_built_service(name, **kwargs)
def _get_set_service(self, name: str):
if name in self._local.set_services:
return self._local.set_services[name]
def _get_built_service(self, name: str, **kwargs):
if self.service_conf[name] and self._has_multiple_creation_methods(name):
raise TooManyCreationMethodsError(self.TOO_MANY_CREATION_METHODS_ERRMSG.format(name))
for service_type, method in self._service_meths.items():
if self.service_conf[name] and service_type in self.service_conf[name]:
return getattr(self, method)(name, **kwargs)
else:
raise NoCreationMethodError(self.NO_CREATION_METHOD_ERRMSG.format(name))
def set(self, name: str, service: any):
self._init_local()
if name not in self.service_conf:
raise UnknownServiceError(self.UNKNOWN_SERVICE_ERRMSG.format(name))
self._local.set_services[name] = service
def _has_multiple_creation_methods(self, name: str):
if not self.service_conf[name]:
raise NoCreationMethodError(self.NO_CREATION_METHOD_ERRMSG.format(name))
return 1 < len([k for k in self._service_meths.keys() if k in self.service_conf[name]])
def _get_service_instance(self, name: str):
if name not in self._local.service_instances:
self._local.service_instances[name] = self.importer.get_obj(self.service_conf[name]['instance'])
return self._local.service_instances[name]
def _instance_service_with_class(self, name: str, **kwargs):
if name not in self._local.service_classes:
self._local.service_classes[name] = self.importer.get_obj(self.service_conf[name]['class'])
return self._local.service_classes[name](*self._get_args(name), **self._get_kwargs(name, **kwargs))
def _instance_service_with_factory(self, name: str, **kwargs):
if name not in self._local.factory_classes:
factory_class = self.importer.get_obj(self.service_conf[name]['factory'])
if not hasattr(factory_class, 'build') or not callable(factory_class.build):
raise NotAServiceFactoryError(self.NOT_A_SERVICE_FACTORY_ERRMSG.format(name))
self._local.factory_classes[name] = factory_class
return self._local.factory_classes[name](*self._get_args(name), **self._get_kwargs(name, **kwargs)).build()
def _get_args(self, name: str):
if 'arguments' in self.service_conf[name]:
return [self._get_arg(ref) for ref in self.service_conf[name]['arguments']]
else:
return []
def _get_kwargs(self, name: str, **kwargs):
named_arguments = {}
for k, v in self.service_conf[name].get('named_arguments', {}).items():
named_arguments[k] = kwargs.get(k, None) or self._get_arg(v)
return named_arguments
def _get_arg(self, ref: any):
if isinstance(ref, str):
if '@' == ref[0]:
return self.get(ref[1:])
elif '%' == ref[0] == ref[-1:]:
return self._get_conf(ref[1:-1])
elif '$' == ref[0]:
return self._get_env(ref[1:])
elif '^' == ref[0]:
return self.importer.get_obj(ref[1:])
elif isinstance(ref, list):
if '$' == ref[0][0]:
return self._get_env(ref[0][1:], ref[1])
else:
return [self._get_arg(i) for i in ref]
return ref # Literal
def _get_conf(self, path: str):
parts = path.split('.')
try:
trunk = self.app_conf[parts[0]]
except KeyError as e:
raise BadConfPathError(self.BAD_CONF_PATH_ERRMSG.format(parts[0]))
try:
return dictpath(trunk, parts[1:])
except KeyError as e:
raise BadConfPathError(self.BAD_CONF_PATH_ERRMSG.format(e.args[0]))
def _get_env(self, var: str, default: any = None):
default = self._get_arg(default)
string = os.environ.get(var, default)
try:
if string:
return literal_eval(string)
except Exception:
pass
return string