x/sqlalchemy-migrate
Code Issues Proposed changes

Fix and test issue 118. Clarify genmodel transformations.

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This commit is contained in:
Gabriel 2011-07-05 00:44:57 +02:00
parent 5cfc74959f
commit 3fe1b4a3be
6 changed files with 159 additions and 99 deletions
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38
migrate/tests/versioning/test_genmodel.py
View File

@ -35,7 +35,7 @@ class TestSchemaDiff(fixture.DB):
def _applyLatestModel(self):
diff = schemadiff.getDiffOfModelAgainstDatabase(self.meta, self.engine, excludeTables=['migrate_version'])
genmodel.ModelGenerator(diff,self.engine).applyModel()
genmodel.ModelGenerator(diff,self.engine).runB2A()
@fixture.usedb()
def test_functional(self):
@ -57,16 +57,30 @@ class TestSchemaDiff(fixture.DB):
# Check Python upgrade and downgrade of database from updated model.
diff = schemadiff.getDiffOfModelAgainstDatabase(self.meta, self.engine, excludeTables=['migrate_version'])
decls, upgradeCommands, downgradeCommands = genmodel.ModelGenerator(diff,self.engine).toUpgradeDowngradePython()
self.assertEqualsIgnoreWhitespace(decls, '''
from migrate.changeset import schema
meta = MetaData()
tmp_schemadiff = Table('tmp_schemadiff', meta,
Column('id', Integer(), primary_key=True, nullable=False),
Column('name', UnicodeText(length=None)),
Column('data', UnicodeText(length=None)),
)
''')
decls, upgradeCommands, downgradeCommands = genmodel.ModelGenerator(diff,self.engine).genB2AMigration()
# Feature test for a recent SQLa feature;
# expect different output in that case.
if repr(String()) == 'String()':
self.assertEqualsIgnoreWhitespace(decls, '''
from migrate.changeset import schema
meta = MetaData()
tmp_schemadiff = Table('tmp_schemadiff', meta,
Column('id', Integer, primary_key=True, nullable=False),
Column('name', UnicodeText),
Column('data', UnicodeText),
)
''')
else:
self.assertEqualsIgnoreWhitespace(decls, '''
from migrate.changeset import schema
meta = MetaData()
tmp_schemadiff = Table('tmp_schemadiff', meta,
Column('id', Integer(), primary_key=True, nullable=False),
Column('name', UnicodeText(length=None)),
Column('data', UnicodeText(length=None)),
)
''')
self.assertEqualsIgnoreWhitespace(upgradeCommands,
'''meta.bind = migrate_engine
tmp_schemadiff.create()''')
@ -80,7 +94,7 @@ class TestSchemaDiff(fixture.DB):
# Check Python code gen from database.
diff = schemadiff.getDiffOfModelAgainstDatabase(MetaData(), self.engine, excludeTables=['migrate_version'])
src = genmodel.ModelGenerator(diff,self.engine).toPython()
src = genmodel.ModelGenerator(diff,self.engine).genBDefinition()
exec src in locals()

51
migrate/tests/versioning/test_script.py
View File

@ -161,23 +161,44 @@ def upgrade(migrate_engine):
self.assertTrue('User.create()' in source_script)
self.assertTrue('User.drop()' in source_script)
#@fixture.usedb()
#def test_make_update_script_for_model_equals(self):
# """Try to make update script from two identical models"""
@fixture.usedb()
def test_make_update_script_for_equal_models(self):
"""Try to make update script from two identical models"""
# self.setup_model_params()
# self.write_file(self.first_model_path, self.base_source + self.model_source)
# self.write_file(self.second_model_path, self.base_source + self.model_source)
self.setup_model_params()
self.write_file(self.first_model_path, self.base_source + self.model_source)
self.write_file(self.second_model_path, self.base_source + self.model_source)
# source_script = self.pyscript.make_update_script_for_model(
# engine=self.engine,
# oldmodel=load_model('testmodel_first:meta'),
# model=load_model('testmodel_second:meta'),
# repository=self.repo_path,
# )
source_script = self.pyscript.make_update_script_for_model(
engine=self.engine,
oldmodel=load_model('testmodel_first:meta'),
model=load_model('testmodel_second:meta'),
repository=self.repo_path,
)
# self.assertFalse('User.create()' in source_script)
# self.assertFalse('User.drop()' in source_script)
self.assertFalse('User.create()' in source_script)
self.assertFalse('User.drop()' in source_script)
@fixture.usedb()
def test_make_update_script_direction(self):
"""Check update scripts go in the right direction"""
self.setup_model_params()
self.write_file(self.first_model_path, self.base_source)
self.write_file(self.second_model_path, self.base_source + self.model_source)
source_script = self.pyscript.make_update_script_for_model(
engine=self.engine,
oldmodel=load_model('testmodel_first:meta'),
model=load_model('testmodel_second:meta'),
repository=self.repo_path,
)
self.assertTrue(0
< source_script.find('upgrade')
< source_script.find('User.create()')
< source_script.find('downgrade')
< source_script.find('User.drop()'))
def setup_model_params(self):
self.script_path = self.tmp_py()
@ -195,6 +216,8 @@ User = Table('User', meta,
self.repo = repository.Repository.create(self.repo_path, 'repo')
self.pyscript = PythonScript.create(self.script_path)
sys.modules.pop('testmodel_first', None)
sys.modules.pop('testmodel_second', None)
def write_file(self, path, contents):
f = open(path, 'w')

51
migrate/versioning/genmodel.py
View File

@ -1,9 +1,9 @@
"""
Code to generate a Python model from a database or differences
between a model and database.
Code to generate a Python model from a database or differences
between a model and database.
Some of this is borrowed heavily from the AutoCode project at:
http://code.google.com/p/sqlautocode/
Some of this is borrowed heavily from the AutoCode project at:
http://code.google.com/p/sqlautocode/
"""
import sys
@ -34,6 +34,13 @@ Base = declarative.declarative_base()
class ModelGenerator(object):
"""Various transformations from an A, B diff.
In the implementation, A tends to be called the model and B
the database (although this is not true of all diffs).
The diff is directionless, but transformations apply the diff
in a particular direction, described in the method name.
"""
def __init__(self, diff, engine, declarative=False):
self.diff = diff
@ -89,7 +96,7 @@ class ModelGenerator(object):
else:
return """Column(%(name)r, %(commonStuff)s)""" % data
def getTableDefn(self, table):
def _getTableDefn(self, table):
out = []
tableName = table.name
if self.declarative:
@ -118,8 +125,14 @@ class ModelGenerator(object):
for name in names:
yield metadata.tables.get(name)
def toPython(self):
"""Assume database is current and model is empty."""
def genBDefinition(self):
"""Generates the source code for a definition of B.
Assumes a diff where A is empty.
Was: toPython. Assume database (B) is current and model (A) is empty.
"""
out = []
if self.declarative:
out.append(DECLARATIVE_HEADER)
@ -127,17 +140,22 @@ class ModelGenerator(object):
out.append(HEADER)
out.append("")
for table in self._get_tables(missingA=True):
out.extend(self.getTableDefn(table))
out.extend(self._getTableDefn(table))
return '\n'.join(out)
def toUpgradeDowngradePython(self, indent=' '):
''' Assume model is most current and database is out-of-date. '''
def genB2AMigration(self, indent=' '):
'''Generate a migration from B to A.
Was: toUpgradeDowngradePython
Assume model (A) is most current and database (B) is out-of-date.
'''
decls = ['from migrate.changeset import schema',
'meta = MetaData()']
for table in self._get_tables(
missingA=True,missingB=True,modified=True
):
decls.extend(self.getTableDefn(table))
decls.extend(self._getTableDefn(table))
upgradeCommands, downgradeCommands = [], []
for tableName in self.diff.tables_missing_from_A:
@ -175,16 +193,21 @@ class ModelGenerator(object):
'\n'.join([pre_command] + ['%s%s' % (indent, line) for line in downgradeCommands]))
def _db_can_handle_this_change(self,td):
"""Check if the database can handle going from B to A."""
if (td.columns_missing_from_B
and not td.columns_missing_from_A
and not td.columns_different):
# Even sqlite can handle this.
# Even sqlite can handle column additions.
return True
else:
return not self.engine.url.drivername.startswith('sqlite')
def applyModel(self):
"""Apply model to current database."""
def runB2A(self):
"""Goes from B to A.
Was: applyModel. Apply model (A) to current database (B).
"""
meta = sqlalchemy.MetaData(self.engine)

4
migrate/versioning/schema.py
View File

@ -117,7 +117,7 @@ class ControlledSchema(object):
diff = schemadiff.getDiffOfModelAgainstDatabase(
model, self.engine, excludeTables=[self.repository.version_table]
)
genmodel.ModelGenerator(diff,self.engine).applyModel()
genmodel.ModelGenerator(diff,self.engine).runB2A()
self.update_repository_table(self.version, int(self.repository.latest))
@ -217,4 +217,4 @@ class ControlledSchema(object):
diff = schemadiff.getDiffOfModelAgainstDatabase(
MetaData(), engine, excludeTables=[repository.version_table]
)
return genmodel.ModelGenerator(diff, engine, declarative).toPython()
return genmodel.ModelGenerator(diff, engine, declarative).genBDefinition()

4
migrate/versioning/script/py.py
View File

@ -61,12 +61,12 @@ class PythonScript(base.BaseScript):
# Compute differences.
diff = schemadiff.getDiffOfModelAgainstModel(
oldmodel,
model,
oldmodel,
excludeTables=[repository.version_table])
# TODO: diff can be False (there is no difference?)
decls, upgradeCommands, downgradeCommands = \
genmodel.ModelGenerator(diff,engine).toUpgradeDowngradePython()
genmodel.ModelGenerator(diff,engine).genB2AMigration()
# Store differences into file.
src = Template(opts.pop('templates_path', None)).get_script(opts.pop('templates_theme', None))