milvus/shards/mishards/routings.py

97 lines
3.0 KiB
Python

import logging
from sqlalchemy import exc as sqlalchemy_exc
from sqlalchemy import and_
from mishards import exceptions, db
from mishards.hash_ring import HashRing
from mishards.models import Tables
logger = logging.getLogger(__name__)
class RouteManager:
ROUTER_CLASSES = {}
@classmethod
def register_router_class(cls, target):
name = target.__dict__.get('NAME', None)
name = name if name else target.__class__.__name__
cls.ROUTER_CLASSES[name] = target
return target
@classmethod
def get_router_class(cls, name):
return cls.ROUTER_CLASSES.get(name, None)
class RouterFactory:
@classmethod
def new_router(cls, name, conn_mgr, **kwargs):
router_class = RouteManager.get_router_class(name)
assert router_class
return router_class(conn_mgr, **kwargs)
class RouterMixin:
def __init__(self, conn_mgr):
self.conn_mgr = conn_mgr
def routing(self, table_name, metadata=None, **kwargs):
raise NotImplemented()
def connection(self, metadata=None):
conn = self.conn_mgr.conn('WOSERVER', metadata=metadata)
if conn:
conn.on_connect(metadata=metadata)
return conn.conn
def query_conn(self, name, metadata=None):
conn = self.conn_mgr.conn(name, metadata=metadata)
if not conn:
raise exceptions.ConnectionNotFoundError(name, metadata=metadata)
conn.on_connect(metadata=metadata)
return conn.conn
@RouteManager.register_router_class
class FileBasedHashRingRouter(RouterMixin):
NAME = 'FileBasedHashRingRouter'
def __init__(self, conn_mgr, **kwargs):
super(FileBasedHashRingRouter, self).__init__(conn_mgr)
def routing(self, table_name, metadata=None, **kwargs):
range_array = kwargs.pop('range_array', None)
return self._route(table_name, range_array, metadata, **kwargs)
def _route(self, table_name, range_array, metadata=None, **kwargs):
# PXU TODO: Implement Thread-local Context
# PXU TODO: Session life mgt
try:
table = db.Session.query(Tables).filter(
and_(Tables.table_id == table_name,
Tables.state != Tables.TO_DELETE)).first()
except sqlalchemy_exc.SQLAlchemyError as e:
raise exceptions.DBError(message=str(e), metadata=metadata)
if not table:
raise exceptions.TableNotFoundError(table_name, metadata=metadata)
files = table.files_to_search(range_array)
db.remove_session()
servers = self.conn_mgr.conn_names
logger.info('Available servers: {}'.format(servers))
ring = HashRing(servers)
routing = {}
for f in files:
target_host = ring.get_node(str(f.id))
sub = routing.get(target_host, None)
if not sub:
routing[target_host] = {'table_id': table_name, 'file_ids': []}
routing[target_host]['file_ids'].append(str(f.id))
return routing