18 lines
755 B
Python
18 lines
755 B
Python
|
"""Two pre-built engines so pool_starvation (phase-0-base-project-spec.md §7)
|
||
|
|
can be toggled live, with no restart: the flag picks which already-initialised
|
||
|
|
pool a request borrows a connection from, rather than resizing a pool in
|
||
|
|
place (SQLAlchemy pools aren't resizable live)."""
|
||
|
|
from sqlalchemy.ext.asyncio import async_sessionmaker
|
||
|
|
|
||
|
|
from common.db import make_engine
|
||
|
|
|
||
|
|
normal_engine = make_engine(pool_size=20, max_overflow=10)
|
||
|
|
starved_engine = make_engine(pool_size=2, max_overflow=0, pool_timeout=10)
|
||
|
|
|
||
|
|
NormalSession = async_sessionmaker(normal_engine, expire_on_commit=False)
|
||
|
|
StarvedSession = async_sessionmaker(starved_engine, expire_on_commit=False)
|
||
|
|
|
||
|
|
|
||
|
|
def session_factory(starved: bool):
|
||
|
|
return StarvedSession() if starved else NormalSession()
|