rattail.trainwreck.handler

Trainwreck Handler

class rattail.trainwreck.handler.TrainwreckHandler(*args, **kwargs)

Handler for Trainwreck data and databases.

current_years()

Returns the number of years which should be kept in the “current” Trainwreck DB.

Note that this refers to the “max” number of years. Rotation is done on a yearly basis, so for instance if the number of years to keep current is 2 (the default), then the actual amount of data in the current DB will vary between 1 years (immediately after Jan 1 pruning) and 2 years (immediately before Jan 1).

In other words if today is Jan 2, and pruning has already occurred, then current DB would have all of last year plus only a day or two from this year. But by the end of this year it will (still) have all of last year, plus all of this year.

engine_is_hidden(key)

Returns a boolean indicating if the given Trainwreck database engine is configured to be hidden from the user interface.

get_hidden_engine_keys()

Return a list of database engine keys which are configured to be hidden from the user interface.

get_model(**kwargs)

Return the data model for Trainwreck.

get_newest_transaction_date(session)

Query a Trainwreck database to determine the date of the “newest” transaction it contains.

Parameters:

session – SQLAlchemy session for a Trainwreck database.

Returns:

A datetime.date instance representing the newest transaction date contained by the database.

get_oldest_transaction_date(session)

Query a Trainwreck database to determine the date of the “oldest” transaction it contains.

Parameters:

session – SQLAlchemy session for a Trainwreck database.

Returns:

A datetime.date instance representing the oldest transaction date contained by the database.

get_trainwreck_engines(include_hidden=True)

Return an “ordered” dict with configured trainwreck DB engines. Keys of the dict will correspond to the config keys for each DB, values will be the engines.

Parameters:

include_hidden – Flag indicating whether the result should include engines which are marked as hidden. Note that hidden engines are included by default.

Returns:

An OrderedDict instance.

make_session(dbkey='default', **kwargs)

Make a session for a Trainwreck DB.

prune_date(session, date, start_time, end_time)

Your custom handler must implement the logic for this method. It is responsible for fully pruning data from the given session’s database, for the given date. The start time and end times given may be used for your queries; they are in localtime and are zone-aware.

use_rotation()

Returns boolean indicating whether rotation should be used, for the Trainwreck DB(s).