87 lines
2.8 KiB
Python
87 lines
2.8 KiB
Python
from __future__ import with_statement
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from alembic import context
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from sqlalchemy import engine_from_config, pool
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from logging.config import fileConfig
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import logging
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# this is the Alembic Config object, which provides
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# access to the values within the .ini file in use.
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config = context.config
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# Interpret the config file for Python logging.
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# This line sets up loggers basically.
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fileConfig(config.config_file_name)
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logger = logging.getLogger('alembic.env')
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# add your model's MetaData object here
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# for 'autogenerate' support
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# from myapp import mymodel
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# target_metadata = mymodel.Base.metadata
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from flask import current_app
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config.set_main_option('sqlalchemy.url',
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current_app.config.get('SQLALCHEMY_DATABASE_URI'))
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target_metadata = current_app.extensions['migrate'].db.metadata
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# other values from the config, defined by the needs of env.py,
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# can be acquired:
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# my_important_option = config.get_main_option("my_important_option")
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# ... etc.
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def run_migrations_offline():
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"""Run migrations in 'offline' mode.
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This configures the context with just a URL
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and not an Engine, though an Engine is acceptable
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here as well. By skipping the Engine creation
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we don't even need a DBAPI to be available.
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Calls to context.execute() here emit the given string to the
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script output.
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"""
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url = config.get_main_option("sqlalchemy.url")
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context.configure(url=url)
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with context.begin_transaction():
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context.run_migrations()
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def run_migrations_online():
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"""Run migrations in 'online' mode.
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In this scenario we need to create an Engine
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and associate a connection with the context.
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"""
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# this callback is used to prevent an auto-migration from being generated
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# when there are no changes to the schema
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# reference: http://alembic.readthedocs.org/en/latest/cookbook.html
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def process_revision_directives(context, revision, directives):
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if getattr(config.cmd_opts, 'autogenerate', False):
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script = directives[0]
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if script.upgrade_ops.is_empty():
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directives[:] = []
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logger.info('No changes in schema detected.')
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engine = engine_from_config(config.get_section(config.config_ini_section),
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prefix='sqlalchemy.',
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poolclass=pool.NullPool)
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connection = engine.connect()
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context.configure(connection=connection,
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target_metadata=target_metadata,
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process_revision_directives=process_revision_directives,
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**current_app.extensions['migrate'].configure_args)
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try:
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with context.begin_transaction():
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context.run_migrations()
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finally:
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connection.close()
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if context.is_offline_mode():
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run_migrations_offline()
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else:
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run_migrations_online()
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