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feat: add alembic config/utility functions, for migrations admin

wuttaweb will have some admin tools exposed soon hopefully
This commit is contained in:
Lance Edgar 2025-12-21 14:29:54 -06:00
parent 5a2748c775
commit 189a53c82a
3 changed files with 216 additions and 8 deletions

View file

@ -2,7 +2,7 @@
################################################################################
#
# WuttJamaican -- Base package for Wutta Framework
# Copyright © 2023-2024 Lance Edgar
# Copyright © 2023-2025 Lance Edgar
#
# This file is part of Wutta Framework.
#
@ -27,6 +27,9 @@ WuttJamaican - database configuration
from collections import OrderedDict
import sqlalchemy as sa
from alembic.config import Config as AlembicConfig
from alembic.script import ScriptDirectory
from alembic.migration import MigrationContext
from wuttjamaican.util import load_object, parse_bool, parse_list
@ -150,3 +153,93 @@ def make_engine_from_config(config_dict, prefix="sqlalchemy.", **kwargs):
engine = sa.engine_from_config(config_dict, prefix, **kwargs)
return engine
##############################
# alembic functions
##############################
def make_alembic_config(config):
"""
Make and return a new Alembic config object, based on current app
config.
This tries to set the following on the Alembic config:
* :attr:`~alembic:alembic.config.Config.config_file_name` - set to
app's primary config file
* main option ``script_location``
* main option ``version_locations``
The latter 2 are read normally from app config, then set on the
Alembic config via
:meth:`~alembic:alembic.config.Config.set_main_option()`.
.. note::
IIUC, Alembic should not need to attempt to read config values
from file, as long as we're able to set the above explicitly.
However we set the ``config_file_name`` "just in case" Alembic
needs it, but also to ensure it is discoverable from within the
``env.py`` script...
When a migration script runs, code within ``env.py`` will call
:func:`make_config()` using the filename which it inspects from
the Alembic config.
(Confused yet?!)
:returns: :class:`alembic:alembic.config.Config` instance
"""
alembic_config = AlembicConfig()
# TODO: not sure what we can do here besides assume the "primary"
# config file should be used?
if config.files_read:
alembic_config.config_file_name = config.get_prioritized_files()[0]
if script_location := config.get("alembic.script_location", usedb=False):
alembic_config.set_main_option("script_location", script_location)
if version_locations := config.get("alembic.version_locations", usedb=False):
alembic_config.set_main_option("version_locations", version_locations)
return alembic_config
def get_alembic_scriptdir(config, alembic_config=None):
"""
Get a "Script Directory" object for Alembic.
This allows for inspection of the migration scripts.
:param config: App config object.
:param alembic_config: Alembic config object, if you have one.
Otherwise :func:`make_alembic_config()` will be called.
:returns: :class:`~alembic:alembic.script.ScriptDirectory` instance
"""
if not alembic_config:
alembic_config = make_alembic_config(config)
return ScriptDirectory.from_config(alembic_config)
def check_alembic_current(config, alembic_config=None):
"""
Compare the current revisions in the :term:`app database` to those
found in the migration scripts.
:param config: App config object.
:param alembic_config: Alembic config object, if you have one.
Otherwise :func:`make_alembic_config()` will be called.
:returns: ``True`` if the DB already has all migrations applied;
``False`` if not.
"""
script = get_alembic_scriptdir(config, alembic_config)
with config.appdb_engine.begin() as conn:
context = MigrationContext.configure(conn)
return set(context.get_current_heads()) == set(script.get_heads())

View file

@ -176,9 +176,10 @@ class ConfigTestCase(FileTestCase):
"""
self.teardown_files()
def make_config(self, **kwargs): # pylint: disable=empty-docstring
""" """
return WuttaConfig(**kwargs)
def make_config( # pylint: disable=missing-function-docstring
self, files=None, **kwargs
):
return WuttaConfig(files, **kwargs)
class DataTestCase(ConfigTestCase):
@ -213,6 +214,8 @@ class DataTestCase(ConfigTestCase):
teardown methods, as this class handles that automatically.
"""
sqlite_engine_url = "sqlite://"
def setUp(self): # pylint: disable=empty-docstring
""" """
self.setup_db()
@ -237,8 +240,7 @@ class DataTestCase(ConfigTestCase):
"""
self.teardown_config()
def make_config(self, **kwargs): # pylint: disable=empty-docstring
""" """
def make_config(self, files=None, **kwargs):
defaults = kwargs.setdefault("defaults", {})
defaults.setdefault("wutta.db.default.url", "sqlite://")
return super().make_config(**kwargs)
defaults.setdefault("wutta.db.default.url", self.sqlite_engine_url)
return super().make_config(files, **kwargs)

View file

@ -6,13 +6,18 @@ import tempfile
from unittest import TestCase
from wuttjamaican.conf import WuttaConfig
from wuttjamaican.testing import ConfigTestCase, DataTestCase
try:
import sqlalchemy as sa
from sqlalchemy import orm
from sqlalchemy.engine import Engine
from sqlalchemy.pool import NullPool
from alembic import command as alembic_command
from alembic.config import Config as AlembicConfig
from alembic.script import ScriptDirectory
from wuttjamaican.db import conf
from wuttjamaican.db import conf as mod
except ImportError:
pass
else:
@ -154,3 +159,111 @@ else:
}
)
self.assertTrue(engine.pool._pre_ping)
class TestMakeAlembicConfig(ConfigTestCase):
def test_defaults(self):
# without config file
self.assertFalse(self.config.files_read)
alembic = mod.make_alembic_config(self.config)
self.assertIsInstance(alembic, AlembicConfig)
self.assertIsNone(alembic.config_file_name)
self.assertIsNone(alembic.get_main_option("script_location"))
self.assertIsNone(alembic.get_main_option("version_locations"))
# with config file
path = self.write_file("test.ini", "[alembic]")
self.config.files_read = [path]
alembic = mod.make_alembic_config(self.config)
self.assertIsInstance(alembic, AlembicConfig)
self.assertEqual(alembic.config_file_name, path)
self.assertIsNone(alembic.get_main_option("script_location"))
self.assertIsNone(alembic.get_main_option("version_locations"))
def test_configured(self):
self.config.setdefault("alembic.script_location", "wuttjamaican.db:alembic")
self.config.setdefault(
"alembic.version_locations", "wuttjamaican.db:alembic/versions"
)
alembic = mod.make_alembic_config(self.config)
self.assertIsInstance(alembic, AlembicConfig)
self.assertEqual(
alembic.get_main_option("script_location"), "wuttjamaican.db:alembic"
)
self.assertEqual(
alembic.get_main_option("version_locations"),
"wuttjamaican.db:alembic/versions",
)
class TestGetAlembicScriptdir(ConfigTestCase):
def test_basic(self):
self.config.setdefault("alembic.script_location", "wuttjamaican.db:alembic")
self.config.setdefault(
"alembic.version_locations", "wuttjamaican.db:alembic/versions"
)
# can provide alembic config
alembic = mod.make_alembic_config(self.config)
script = mod.get_alembic_scriptdir(self.config, alembic)
self.assertIsInstance(script, ScriptDirectory)
# but also can omit it
script = mod.get_alembic_scriptdir(self.config)
self.assertIsInstance(script, ScriptDirectory)
class TestCheckAlembicCurrent(DataTestCase):
def make_config(self, **kwargs):
sqlite_path = self.write_file("test.sqlite", "")
self.sqlite_engine_url = f"sqlite:///{sqlite_path}"
config_path = self.write_file(
"test.ini",
f"""
[wutta.db]
default.url = {self.sqlite_engine_url}
[alembic]
script_location = wuttjamaican.db:alembic
version_locations = wuttjamaican.db:alembic/versions
""",
)
return super().make_config([config_path], **kwargs)
def test_basic(self):
alembic = mod.make_alembic_config(self.config)
self.assertIsNotNone(alembic.get_main_option("script_location"))
self.assertIsNotNone(alembic.get_main_option("version_locations"))
# false by default, since tests use MetaData.create_all()
# instead of migrations for setup
self.assertFalse(mod.check_alembic_current(self.config, alembic))
# and to further prove the point, alembic_version table is missing
self.assertEqual(
self.session.execute(sa.text("select count(*) from person")).scalar(),
0,
)
self.assertRaises(
sa.exc.OperationalError,
self.session.execute,
sa.text("select count(*) from alembic_version"),
)
# but we can 'stamp' the DB to declare its current revision
alembic_command.stamp(alembic, "heads")
# now the alembic_version table exists
self.assertEqual(
self.session.execute(
sa.text("select count(*) from alembic_version")
).scalar(),
1,
)
# and now Alembic knows we are current
self.assertTrue(mod.check_alembic_current(self.config, alembic))