mediagoblin/db/migrations/env.py

   1 from __future__ import with_statement
   2 from alembic import context
   3 from sqlalchemy import engine_from_config, pool
   4 from logging.config import fileConfig
   5
   6 # this is the Alembic Config object, which provides
   7 # access to the values within the .ini file in use.
   8 config = context.config
   9
  10 # Interpret the config file for Python logging.
  11 # This line sets up loggers basically.
  12 fileConfig(config.config_file_name)
  13
  14 # add your model's MetaData object here
  15 # for 'autogenerate' support
  16 # from myapp import mymodel
  17 # target_metadata = mymodel.Base.metadata
  18 target_metadata = None
  19
  20 # other values from the config, defined by the needs of env.py,
  21 # can be acquired:
  22 # my_important_option = config.get_main_option("my_important_option")
  23 # ... etc.
  24
  25 def run_migrations_offline():
  26     """Run migrations in 'offline' mode.
  27
  28     This configures the context with just a URL
  29     and not an Engine, though an Engine is acceptable
  30     here as well.  By skipping the Engine creation
  31     we don't even need a DBAPI to be available.
  32
  33     Calls to context.execute() here emit the given string to the
  34     script output.
  35
  36     """
  37     url = config.get_main_option("sqlalchemy.url")
  38     context.configure(url=url, target_metadata=target_metadata)
  39
  40     with context.begin_transaction():
  41         context.run_migrations()
  42
  43 def run_migrations_online():
  44     """Run migrations in 'online' mode.
  45
  46     In this scenario we need to create an Engine
  47     and associate a connection with the context.
  48
  49     """
  50     engine = engine_from_config(
  51                 config.get_section(config.config_ini_section),
  52                 prefix='sqlalchemy.',
  53                 poolclass=pool.NullPool)
  54
  55     connection = engine.connect()
  56     context.configure(
  57                 connection=connection,
  58                 target_metadata=target_metadata
  59                 )
  60
  61     try:
  62         with context.begin_transaction():
  63             context.run_migrations()
  64     finally:
  65         connection.close()
  66
  67 if context.is_offline_mode():
  68     run_migrations_offline()
  69 else:
  70     run_migrations_online()
  71