Files
jupyterhub/jupyterhub/dbutil.py
2017-08-11 16:46:19 -07:00

97 lines
2.9 KiB
Python

"""Database utilities for JupyterHub"""
# Copyright (c) Jupyter Development Team.
# Distributed under the terms of the Modified BSD License.
# Based on pgcontents.utils.migrate, used under the Apache license.
from contextlib import contextmanager
import os
from subprocess import check_call
import sys
from tempfile import TemporaryDirectory
_here = os.path.abspath(os.path.dirname(__file__))
ALEMBIC_INI_TEMPLATE_PATH = os.path.join(_here, 'alembic.ini')
ALEMBIC_DIR = os.path.join(_here, 'alembic')
def write_alembic_ini(alembic_ini='alembic.ini', db_url='sqlite:///jupyterhub.sqlite'):
"""Write a complete alembic.ini from our template.
Parameters
----------
alembic_ini: str
path to the alembic.ini file that should be written.
db_url: str
The SQLAlchemy database url, e.g. `sqlite:///jupyterhub.sqlite`.
"""
with open(ALEMBIC_INI_TEMPLATE_PATH) as f:
alembic_ini_tpl = f.read()
with open(alembic_ini, 'w') as f:
f.write(
alembic_ini_tpl.format(
alembic_dir=ALEMBIC_DIR,
# If there are any %s in the URL, they should be replaced with %%, since ConfigParser
# by default uses %() for substitution. You'll get %s in your URL when you have usernames
# with special chars (such as '@') that need to be URL encoded. URL Encoding is done with %s.
# YAY for nested templates?
db_url=str(db_url).replace('%', '%%'),
)
)
@contextmanager
def _temp_alembic_ini(db_url):
"""Context manager for temporary JupyterHub alembic directory
Temporarily write an alembic.ini file for use with alembic migration scripts.
Context manager yields alembic.ini path.
Parameters
----------
db_url: str
The SQLAlchemy database url, e.g. `sqlite:///jupyterhub.sqlite`.
Returns
-------
alembic_ini: str
The path to the temporary alembic.ini that we have created.
This file will be cleaned up on exit from the context manager.
"""
with TemporaryDirectory() as td:
alembic_ini = os.path.join(td, 'alembic.ini')
write_alembic_ini(alembic_ini, db_url)
yield alembic_ini
def upgrade(db_url, revision='head'):
"""Upgrade the given database to revision.
db_url: str
The SQLAlchemy database url, e.g. `sqlite:///jupyterhub.sqlite`.
revision: str [default: head]
The alembic revision to upgrade to.
"""
with _temp_alembic_ini(db_url) as alembic_ini:
check_call(
['alembic', '-c', alembic_ini, 'upgrade', revision]
)
def _alembic(*args):
"""Run an alembic command with a temporary alembic.ini"""
with _temp_alembic_ini('sqlite:///jupyterhub.sqlite') as alembic_ini:
check_call(
['alembic', '-c', alembic_ini] + list(args)
)
if __name__ == '__main__':
_alembic(*sys.argv[1:])