milvus/shards/mishards/router/plugins/file_based_hash_ring_router.py
2019-11-06 16:47:38 +08:00

65 lines
2.1 KiB
Python

import logging
from sqlalchemy import exc as sqlalchemy_exc
from sqlalchemy import and_
from mishards.models import Tables
from mishards.router import RouterMixin
from mishards import exceptions, db
from mishards.hash_ring import HashRing
logger = logging.getLogger(__name__)
class Factory(RouterMixin):
name = 'FileBasedHashRingRouter'
def __init__(self, conn_mgr, **kwargs):
super(Factory, 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
@classmethod
def Create(cls, **kwargs):
conn_mgr = kwargs.pop('conn_mgr', None)
if not conn_mgr:
raise RuntimeError('Cannot find \'conn_mgr\' to initialize \'{}\''.format(self.name))
router = cls(conn_mgr, **kwargs)
return router
def setup(app):
logger.info('Plugin \'{}\' Installed In Package: {}'.format(__file__, app.plugin_package_name))
app.on_plugin_setup(Factory)