Script Directory

The ScriptDirectory object provides programmatic accessto the Alembic version files present in the filesystem.

• class alembic.script. Script (module: module, rev_id: str, path: str)

  Represent a single revision file in a directory.

  The Script instance is returned by methodssuch as ScriptDirectory.iterate_revisions() .

  • propertydoc**:str*

    Return the docstring given in the script.

  • property longdoc : str

    Return the docstring given in the script.

  • module : module = None

    The Python module representing the actual script itself.

  • path : str = None

    Filesystem path of the script.

• class alembic.script. ScriptDirectory (dir: str, file_template: str = '%(rev)s_%(slug)s', truncate_slug_length: Optional[int] = 40, version_locations: Optional[List[str]] = None, sourceless: bool = False, output_encoding: str = 'utf-8', timezone: Optional[str] = None, hook_config: Optional[Dict[str, str]] = None)

  Provides operations upon an Alembic script directory.

  This object is useful to get information as to current revisions, most notably being able to get at the “head” revision, for schemes that want to test if the current revision in the database is the most recent:

  from alembic.script import ScriptDirectory
  from alembic.config import Config
  config = Config()
  config.set_main_option("script_location", "myapp:migrations")
  script = ScriptDirectory.from_config(config)
  
  head_revision = script.get_current_head()
  

  • classmethod from_config (config: Config) → ScriptDirectory

    Produce a new ScriptDirectory given a Config instance.

    The Config need only have the script_location key present.

  • generate_revision (revid: str, message: Optional[str], head: Optional[str] = None, refresh: bool = False, splice: Optional[bool] = False, branch_labels: Optional[str] = None, version_path: Optional[str] = None, depends_on: Optional[Union[str, Sequence[str]]] = None, **kw: Any) → Optional[alembic.script.base.Script]

    Generate a new revision file.

    This runs the template, giventemplate arguments, and creates a new file.

    Parameters

    • [revid] - String revision id. Typically thiscomes from alembic.util.rev_id() .
    • [message] - the revision message, the one passedby the -m argument to the revision command.
    • [head] - the head revision to generate against. Defaultsto the current âheadâ if True, allow the âheadâ deprecated.

  • get_base () → Optional[str]

    Return the âbaseâbaseâversioned headâll get nothing back.

    The iterator yields Script objects.

  • run_env () → None

    Run the script environment.

    This basically runs the env.py script presentin the migration environment. It is called exclusivelyby the command functions in alembic.command .

  • walk_revisions (base: str = 'base', head: str = 'heads') → Iterator[alembic.script.base.Script]

    Iterate through all revisions.

    Parameters

    • [base] - the base revision, or âbaseâ the head revision; defaults to âheadsâheadâs branch
    • [head] – the head revision; defaults to “heads” to indicateall head revisions. May also be “heads” to indicate a singlehead revision.