mirror of
https://github.com/Foundry376/Mailspring.git
synced 2024-11-12 12:40:08 +08:00
78 lines
2.3 KiB
Python
78 lines
2.3 KiB
Python
|
|
from contextlib import contextmanager
|
|
|
|
from sqlalchemy.orm.session import Session
|
|
from sqlalchemy import create_engine
|
|
import os
|
|
|
|
|
|
cached_engine = None
|
|
|
|
|
|
def new_engine(database="quickschedule"):
|
|
db_url = os.environ['CLEARDB_DATABASE_URL']
|
|
if db_url:
|
|
uri = 'mysql+pymysql'+db_url[5:].split('?')[0]
|
|
else:
|
|
uri_template = ("mysql+pymysql://{username}:{password}@{host}:"
|
|
"{port}/{database}")
|
|
uri = uri_template.format(username="root",
|
|
password="root",
|
|
host="localhost",
|
|
port=3307,
|
|
database=database if database else '')
|
|
return create_engine(uri,
|
|
isolation_level='READ COMMITTED',
|
|
echo=False,
|
|
connect_args={'charset': 'utf8mb4'})
|
|
|
|
|
|
def new_session(engine, versioned=True):
|
|
"""Returns a session bound to the given engine."""
|
|
session = Session(bind=engine, autoflush=True, autocommit=False)
|
|
return session
|
|
|
|
|
|
@contextmanager
|
|
def session_scope(debug=False):
|
|
"""
|
|
Provide a transactional scope around a series of operations.
|
|
|
|
Takes care of rolling back failed transactions and closing the session
|
|
when it goes out of scope.
|
|
|
|
Note that sqlalchemy automatically starts a new database transaction when
|
|
the session is created, and restarts a new transaction after every commit()
|
|
on the session. Your database backend's transaction semantics are important
|
|
here when reasoning about concurrency.
|
|
|
|
Parameters
|
|
----------
|
|
versioned : bool
|
|
Do you want to enable the transaction log?
|
|
debug : bool
|
|
Do you want to turn on SQL echoing? Use with caution. Engine is not
|
|
cached in this case!
|
|
|
|
Yields
|
|
------
|
|
Session
|
|
The created session.
|
|
|
|
"""
|
|
global cached_engine
|
|
if cached_engine is None:
|
|
cached_engine = new_engine()
|
|
# log.info("Don't yet have engine... creating default from ignition",
|
|
# engine=id(cached_engine))
|
|
|
|
session = new_session(cached_engine)
|
|
try:
|
|
yield session
|
|
session.commit()
|
|
except BaseException as exc:
|
|
session.rollback()
|
|
print exc
|
|
raise
|
|
finally:
|
|
session.close()
|