Data sources¶

The process-wide data source, used when nothing more specific was given.

sources ¶

The process-level data source: what answers when nothing was bound.

import beacon
beacon.use(fetcher)          # point the process somewhere, once
p.asset("AAA").prices(...)   # every unbound portfolio reads it

A source bound to the object wins: a backtest result's views always read the data its run used. This module is the fallback for objects that have none, resolved in this order:

a source set explicitly with :func:use;
otherwise the default store on disk (the one python -m beacon.synthetic writes and the server auto-loads), loaded lazily on first need and cached;
if neither exists, a :class:DataSourceError that names both fixes.

The source is process-global, so results that read it depend on process state. Objects that must be reproducible, such as backtest results, carry their own binding, which always wins.

use ¶

use(fetcher: DataFetcher | None) -> None

Set the process's data source, or clear it with None.

Parameters:

Name	Type	Description	Default
`fetcher`	`DataFetcher \| None`	What unbound reads should resolve against, or None to fall back to the default store again.	required

resolve ¶

resolve() -> DataFetcher

The data source an unbound read should use.

Returns:

Name	Type	Description
`DataFetcher`	`DataFetcher`	The explicit source when one was set, else the default
	`DataFetcher`	store, loaded lazily on first call and cached for the process.

Raises:

Type	Description
`DataSourceError`	When neither exists. The message names both fixes.