385 lines
13 KiB
Python
385 lines
13 KiB
Python
"""
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This module provides an external API to the versioning system.
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.. versionchanged:: 0.6.0
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:func:`migrate.versioning.api.test` and schema diff functions
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changed order of positional arguments so all accept `url` and `repository`
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as first arguments.
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.. versionchanged:: 0.5.4
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``--preview_sql`` displays source file when using SQL scripts.
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If Python script is used, it runs the action with mocked engine and
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returns captured SQL statements.
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.. versionchanged:: 0.5.4
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Deprecated ``--echo`` parameter in favour of new
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:func:`migrate.versioning.util.construct_engine` behavior.
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"""
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# Dear migrate developers,
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#
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# please do not comment this module using sphinx syntax because its
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# docstrings are presented as user help and most users cannot
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# interpret sphinx annotated ReStructuredText.
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#
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# Thanks,
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# Jan Dittberner
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import sys
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import inspect
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import logging
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from migrate import exceptions
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from migrate.versioning import (repository, schema, version,
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script as script_) # command name conflict
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from migrate.versioning.util import catch_known_errors, with_engine
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log = logging.getLogger(__name__)
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command_desc = {
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'help': 'displays help on a given command',
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'create': 'create an empty repository at the specified path',
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'script': 'create an empty change Python script',
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'script_sql': 'create empty change SQL scripts for given database',
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'version': 'display the latest version available in a repository',
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'db_version': 'show the current version of the repository under version control',
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'source': 'display the Python code for a particular version in this repository',
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'version_control': 'mark a database as under this repository\'s version control',
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'upgrade': 'upgrade a database to a later version',
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'downgrade': 'downgrade a database to an earlier version',
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'drop_version_control': 'removes version control from a database',
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'manage': 'creates a Python script that runs Migrate with a set of default values',
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'test': 'performs the upgrade and downgrade command on the given database',
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'compare_model_to_db': 'compare MetaData against the current database state',
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'create_model': 'dump the current database as a Python model to stdout',
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'make_update_script_for_model': 'create a script changing the old MetaData to the new (current) MetaData',
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'update_db_from_model': 'modify the database to match the structure of the current MetaData',
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}
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__all__ = command_desc.keys()
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Repository = repository.Repository
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ControlledSchema = schema.ControlledSchema
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VerNum = version.VerNum
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PythonScript = script_.PythonScript
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SqlScript = script_.SqlScript
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# deprecated
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def help(cmd=None, **opts):
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"""%prog help COMMAND
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Displays help on a given command.
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"""
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if cmd is None:
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raise exceptions.UsageError(None)
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try:
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func = globals()[cmd]
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except:
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raise exceptions.UsageError(
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"'%s' isn't a valid command. Try 'help COMMAND'" % cmd)
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ret = func.__doc__
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if sys.argv[0]:
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ret = ret.replace('%prog', sys.argv[0])
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return ret
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@catch_known_errors
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def create(repository, name, **opts):
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"""%prog create REPOSITORY_PATH NAME [--table=TABLE]
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Create an empty repository at the specified path.
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You can specify the version_table to be used; by default, it is
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'migrate_version'. This table is created in all version-controlled
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databases.
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"""
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repo_path = Repository.create(repository, name, **opts)
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@catch_known_errors
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def script(description, repository, **opts):
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"""%prog script DESCRIPTION REPOSITORY_PATH
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Create an empty change script using the next unused version number
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appended with the given description.
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For instance, manage.py script "Add initial tables" creates:
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repository/versions/001_Add_initial_tables.py
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"""
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repo = Repository(repository)
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repo.create_script(description, **opts)
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@catch_known_errors
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def script_sql(database, description, repository, **opts):
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"""%prog script_sql DATABASE DESCRIPTION REPOSITORY_PATH
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Create empty change SQL scripts for given DATABASE, where DATABASE
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is either specific ('postgresql', 'mysql', 'oracle', 'sqlite', etc.)
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or generic ('default').
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For instance, manage.py script_sql postgresql description creates:
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repository/versions/001_description_postgresql_upgrade.sql and
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repository/versions/001_description_postgresql_downgrade.sql
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"""
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repo = Repository(repository)
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repo.create_script_sql(database, description, **opts)
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def version(repository, **opts):
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"""%prog version REPOSITORY_PATH
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Display the latest version available in a repository.
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"""
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repo = Repository(repository)
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return repo.latest
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@with_engine
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def db_version(url, repository, **opts):
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"""%prog db_version URL REPOSITORY_PATH
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Show the current version of the repository with the given
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connection string, under version control of the specified
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repository.
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The url should be any valid SQLAlchemy connection string.
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"""
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engine = opts.pop('engine')
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schema = ControlledSchema(engine, repository)
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return schema.version
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def source(version, dest=None, repository=None, **opts):
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"""%prog source VERSION [DESTINATION] --repository=REPOSITORY_PATH
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Display the Python code for a particular version in this
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repository. Save it to the file at DESTINATION or, if omitted,
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send to stdout.
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"""
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if repository is None:
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raise exceptions.UsageError("A repository must be specified")
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repo = Repository(repository)
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ret = repo.version(version).script().source()
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if dest is not None:
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dest = open(dest, 'w')
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dest.write(ret)
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dest.close()
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ret = None
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return ret
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def upgrade(url, repository, version=None, **opts):
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"""%prog upgrade URL REPOSITORY_PATH [VERSION] [--preview_py|--preview_sql]
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Upgrade a database to a later version.
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This runs the upgrade() function defined in your change scripts.
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By default, the database is updated to the latest available
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version. You may specify a version instead, if you wish.
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You may preview the Python or SQL code to be executed, rather than
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actually executing it, using the appropriate 'preview' option.
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"""
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err = "Cannot upgrade a database of version %s to version %s. "\
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"Try 'downgrade' instead."
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return _migrate(url, repository, version, upgrade=True, err=err, **opts)
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def downgrade(url, repository, version, **opts):
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"""%prog downgrade URL REPOSITORY_PATH VERSION [--preview_py|--preview_sql]
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Downgrade a database to an earlier version.
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This is the reverse of upgrade; this runs the downgrade() function
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defined in your change scripts.
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You may preview the Python or SQL code to be executed, rather than
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actually executing it, using the appropriate 'preview' option.
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"""
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err = "Cannot downgrade a database of version %s to version %s. "\
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"Try 'upgrade' instead."
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return _migrate(url, repository, version, upgrade=False, err=err, **opts)
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@with_engine
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def test(url, repository, **opts):
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"""%prog test URL REPOSITORY_PATH [VERSION]
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Performs the upgrade and downgrade option on the given
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database. This is not a real test and may leave the database in a
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bad state. You should therefore better run the test on a copy of
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your database.
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"""
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engine = opts.pop('engine')
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repos = Repository(repository)
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# Upgrade
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log.info("Upgrading...")
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script = repos.version(None).script(engine.name, 'upgrade')
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script.run(engine, 1)
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log.info("done")
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log.info("Downgrading...")
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script = repos.version(None).script(engine.name, 'downgrade')
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script.run(engine, -1)
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log.info("done")
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log.info("Success")
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@with_engine
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def version_control(url, repository, version=None, **opts):
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"""%prog version_control URL REPOSITORY_PATH [VERSION]
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Mark a database as under this repository's version control.
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Once a database is under version control, schema changes should
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only be done via change scripts in this repository.
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This creates the table version_table in the database.
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The url should be any valid SQLAlchemy connection string.
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By default, the database begins at version 0 and is assumed to be
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empty. If the database is not empty, you may specify a version at
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which to begin instead. No attempt is made to verify this
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version's correctness - the database schema is expected to be
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identical to what it would be if the database were created from
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scratch.
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"""
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engine = opts.pop('engine')
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ControlledSchema.create(engine, repository, version)
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@with_engine
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def drop_version_control(url, repository, **opts):
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"""%prog drop_version_control URL REPOSITORY_PATH
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Removes version control from a database.
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"""
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engine = opts.pop('engine')
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schema = ControlledSchema(engine, repository)
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schema.drop()
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def manage(file, **opts):
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"""%prog manage FILENAME [VARIABLES...]
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Creates a script that runs Migrate with a set of default values.
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For example::
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%prog manage manage.py --repository=/path/to/repository \
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--url=sqlite:///project.db
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would create the script manage.py. The following two commands
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would then have exactly the same results::
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python manage.py version
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%prog version --repository=/path/to/repository
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"""
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Repository.create_manage_file(file, **opts)
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@with_engine
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def compare_model_to_db(url, repository, model, **opts):
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"""%prog compare_model_to_db URL REPOSITORY_PATH MODEL
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Compare the current model (assumed to be a module level variable
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of type sqlalchemy.MetaData) against the current database.
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NOTE: This is EXPERIMENTAL.
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""" # TODO: get rid of EXPERIMENTAL label
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engine = opts.pop('engine')
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return ControlledSchema.compare_model_to_db(engine, model, repository)
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@with_engine
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def create_model(url, repository, **opts):
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"""%prog create_model URL REPOSITORY_PATH [DECLERATIVE=True]
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Dump the current database as a Python model to stdout.
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NOTE: This is EXPERIMENTAL.
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""" # TODO: get rid of EXPERIMENTAL label
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engine = opts.pop('engine')
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declarative = opts.get('declarative', False)
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return ControlledSchema.create_model(engine, repository, declarative)
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@catch_known_errors
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@with_engine
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def make_update_script_for_model(url, repository, oldmodel, model, **opts):
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"""%prog make_update_script_for_model URL OLDMODEL MODEL REPOSITORY_PATH
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Create a script changing the old Python model to the new (current)
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Python model, sending to stdout.
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NOTE: This is EXPERIMENTAL.
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""" # TODO: get rid of EXPERIMENTAL label
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engine = opts.pop('engine')
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return PythonScript.make_update_script_for_model(
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engine, oldmodel, model, repository, **opts)
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@with_engine
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def update_db_from_model(url, repository, model, **opts):
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"""%prog update_db_from_model URL REPOSITORY_PATH MODEL
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Modify the database to match the structure of the current Python
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model. This also sets the db_version number to the latest in the
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repository.
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NOTE: This is EXPERIMENTAL.
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""" # TODO: get rid of EXPERIMENTAL label
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engine = opts.pop('engine')
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schema = ControlledSchema(engine, repository)
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schema.update_db_from_model(model)
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@with_engine
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def _migrate(url, repository, version, upgrade, err, **opts):
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engine = opts.pop('engine')
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url = str(engine.url)
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schema = ControlledSchema(engine, repository)
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version = _migrate_version(schema, version, upgrade, err)
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changeset = schema.changeset(version)
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for ver, change in changeset:
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nextver = ver + changeset.step
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log.info('%s -> %s... ', ver, nextver)
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if opts.get('preview_sql'):
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if isinstance(change, PythonScript):
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log.info(change.preview_sql(url, changeset.step, **opts))
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elif isinstance(change, SqlScript):
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log.info(change.source())
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elif opts.get('preview_py'):
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if not isinstance(change, PythonScript):
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raise exceptions.UsageError("Python source can be only displayed"
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" for python migration files")
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source_ver = max(ver, nextver)
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module = schema.repository.version(source_ver).script().module
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funcname = upgrade and "upgrade" or "downgrade"
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func = getattr(module, funcname)
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log.info(inspect.getsource(func))
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else:
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schema.runchange(ver, change, changeset.step)
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log.info('done')
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def _migrate_version(schema, version, upgrade, err):
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if version is None:
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return version
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# Version is specified: ensure we're upgrading in the right direction
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# (current version < target version for upgrading; reverse for down)
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version = VerNum(version)
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cur = schema.version
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if upgrade is not None:
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if upgrade:
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direction = cur <= version
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else:
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direction = cur >= version
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if not direction:
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raise exceptions.KnownError(err % (cur, version))
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return version
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