BitLogger/docs/api/library-logger-with-target.md

name, group, category, update-time, description, key-word

name	group	category	update-time	description	key-word
library-logger-with-target	api	facade	20260613	Replace the default target carried by a LibraryLogger facade while rewrapping the same underlying logger state.	library facade target public

Library-logger-with-target

Replace the default target on a LibraryLogger[S]. This is the library-facing counterpart to Logger::with_target(...) when a package wants to retarget a logger without exposing the full sync logger API.

Interface

pub fn[S] LibraryLogger::with_target(self : LibraryLogger[S], target : String) -> LibraryLogger[S] {

input

• self : LibraryLogger[S] - Base facade whose default target should be replaced.
• target : String - New default target namespace.

output

• LibraryLogger[S] - New library-facing logger facade carrying the updated target.

Explanation

Detailed rules explaining key parameters and behaviors

• This API delegates to the wrapped logger's with_target(...) behavior and then re-wraps the result.
• The returned value keeps the same sink type, minimum level, timestamp behavior, and any existing sink wrappers because only the default target field changes.
• This replaces the default target instead of composing it.
• Broader composition helpers remain hidden behind the narrower facade after rewrapping; use to_logger() if later code needs them.
• The original facade value is not mutated.

How to Use

Here are some specific examples provided.

When Need A New Fixed Namespace Inside Library Code

When one facade should emit under a different target namespace:

let logger = default_library_logger().with_target("sdk.http")
logger.info("request prepared")

In this example, later writes inherit sdk.http unless a call overrides the target directly.

When Reuse The Same Sink Across Several Library Subsystems

When multiple library-facing loggers should share one base pipeline:

let base = LibraryLogger::new(console_sink())
let cache = base.with_target("cache")
let io = base.with_target("io")

In this example, one base facade becomes several target-specific facades.

And each derived facade still wraps the same logger pipeline, differing only in the default target it carries.

Error Case

e.g.:

• If target is empty, the returned logger remains valid and later records simply use an empty default target.

• If callers need hierarchical target composition rather than replacement, child(...) is the better API.

Notes

1. Use this API for replacement, not target-path composition.

2. It keeps the narrower LibraryLogger boundary intact.

3. Use child(...) when the new target should be combined with the current one instead of replacing it.