NoteApi

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from __future__ import with_statement
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import logging
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from logging.config import fileConfig
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from flask import current_app
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from alembic import context
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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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config.set_main_option(
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    'sqlalchemy.url',
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    str(current_app.extensions['migrate'].db.engine.url).replace('%', '%%'))
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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(
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        url=url, target_metadata=target_metadata, literal_binds=True
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    )
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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.zzzcomputing.com/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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    connectable = current_app.extensions['migrate'].db.engine
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    with connectable.connect() as connection:
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        context.configure(
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            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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        )
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        with context.begin_transaction():
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            context.run_migrations()
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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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