core-extra/daemon/core/configservice/manager.py

81 lines
2.6 KiB
Python

import logging
import pathlib
from typing import Dict, List, Type
from core import utils
from core.configservice.base import ConfigService
from core.errors import CoreError
class ConfigServiceManager:
"""
Manager for configurable services.
"""
def __init__(self):
"""
Create a ConfigServiceManager instance.
"""
self.services: Dict[str, Type[ConfigService]] = {}
def get_service(self, name: str) -> Type[ConfigService]:
"""
Retrieve a service by name.
:param name: name of service
:return: service class
:raises CoreError: when service is not found
"""
service_class = self.services.get(name)
if service_class is None:
raise CoreError(f"service does not exit {name}")
return service_class
def add(self, service: Type[ConfigService]) -> None:
"""
Add service to manager, checking service requirements have been met.
:param service: service to add to manager
:return: nothing
:raises CoreError: when service is a duplicate or has unmet executables
"""
name = service.name
logging.debug(
"loading service: class(%s) name(%s)", service.__class__.__name__, name
)
# avoid duplicate services
if name in self.services:
raise CoreError(f"duplicate service being added: {name}")
# validate dependent executables are present
for executable in service.executables:
try:
utils.which(executable, required=True)
except CoreError as e:
raise CoreError(f"config service({service.name}): {e}")
# make service available
self.services[name] = service
def load(self, path: str) -> List[str]:
"""
Search path provided for configurable services and add them for being managed.
:param path: path to search configurable services
:return: list errors when loading and adding services
"""
path = pathlib.Path(path)
subdirs = [x for x in path.iterdir() if x.is_dir()]
subdirs.append(path)
service_errors = []
for subdir in subdirs:
logging.debug("loading config services from: %s", subdir)
services = utils.load_classes(str(subdir), ConfigService)
for service in services:
try:
self.add(service)
except CoreError as e:
service_errors.append(service.name)
logging.debug("not loading service(%s): %s", service.name, e)
return service_errors