valarpy.connection

Module Contents

class valarpy.connection.Valar(config: Union[None, str, pathlib.Path, List[Union[str, pathlib.Path, None]], Mapping[str, Union[str, int]]] = None)

Global valarpy connection.

Constructor.

Parameters

config – The connection info, which must contain “database” and optionally parameters passed to peewee If a dict, used as-is. If a path or str, attempts to read JSON from that path. If a list of paths, strs, and Nones, reads from the first extant file found in the list. If None, attempts to read JSON from the VALARPY_CONFIG environment variable, if set.

Raises

• FileNotFoundError – If a path was supplied but does not point to a file

• TypeError – If the type was not recognized

• InterfaceError – On some connection issues

classmethod find_extant_path(*paths: Union[pathlib.Path, str, None]) → pathlib.Path

Finds the first extant path in the list. It is rare to need to call this directly.

Parameters

*paths – A list of file paths; values of None are skipped

Returns

The first Path that exists

Raises

FileNotFoundError – If the path found is not a file

classmethod get_preferred_paths() → List[pathlib.Path]

Gets a list of preferred paths to look for config files, in order from highest-priority to least-priority. Starts with the VALARPY_CONFIG environment variable, if it is set.

Returns: A list of Path instances

rolling_back() → Generator[peewee._transaction, None, None]

Starts a transaction or savepoint that will be rolled back whether it fails or succeeds. Useful for testing.

Yields

A peewee Transaction type; this should generally not be used

atomic() → Generator[peewee._transaction, None, None]

Starts a transaction or savepoint that will be rolled back only on failure.

Yields

A peewee Transaction type; this should generally not be used

Examples

Here, both testing1 and testing2 are created atomically in a single transaction, or neither are created on failure because the transaction is automatically rolled back.

@valar.atomic def create_stuff():

Refs(name=”testing1”).save() Refs(name=”testing2”).save()

reconnect(hard: bool = False) → None

Closes and then opens the connection. This may be useful for fixing connection issues.

Parameters

hard – Forcibly close and re-open connection

open() → None

Opens the database connection. This is already called by __enter__.

close() → None

Closes the connection. This is already called by __exit__.