mirror of
https://github.com/Nanaloveyuki/BitLogger.git
synced 2026-07-24 00:42:18 +00:00
Nanaloveyuki
95 lines
3.6 KiB
Markdown
95 lines
3.6 KiB
Markdown
---
|
|
name: library-async-logger-with-context-fields
|
|
group: api
|
|
category: facade
|
|
update-time: 20260613
|
|
description: Attach reusable structured fields to a LibraryAsyncLogger facade while rewrapping the same underlying async logger state.
|
|
key-word:
|
|
- async
|
|
- library
|
|
- fields
|
|
- public
|
|
---
|
|
|
|
## Library-async-logger-with-context-fields
|
|
|
|
Bind shared structured fields to a `LibraryAsyncLogger[S]`. This is the library-facing API for attaching stable metadata such as component name, plugin id, or request scope without repeating those fields on every async log call.
|
|
|
|
### Interface
|
|
|
|
```moonbit
|
|
pub fn[S] LibraryAsyncLogger::with_context_fields(
|
|
self : LibraryAsyncLogger[S],
|
|
fields : Array[@bitlogger.Field],
|
|
) -> LibraryAsyncLogger[S] {
|
|
```
|
|
|
|
#### input
|
|
|
|
- `self : LibraryAsyncLogger[S]` - Base facade that should gain shared fields.
|
|
- `fields : Array[@bitlogger.Field]` - Structured fields stored on the facade and prepended to each emitted record.
|
|
|
|
#### output
|
|
|
|
- `LibraryAsyncLogger[S]` - New library-facing async facade carrying the shared field set.
|
|
|
|
### Explanation
|
|
|
|
Detailed rules explaining key parameters and behaviors
|
|
|
|
- This API delegates to the wrapped async logger's `with_context_fields(...)` behavior and then narrows the result back to `LibraryAsyncLogger`.
|
|
- The provided `fields` array replaces the previously stored shared context field set on the wrapped async logger.
|
|
- During later `log(...)` calls, those stored shared fields are prepended ahead of per-call fields before enqueue.
|
|
- Sink type, queue state, async config, and failure/lifecycle state remain the same because only the stored shared field set changes.
|
|
- Unlike synchronous `LibraryLogger::with_context_fields(...)`, this async variant preserves the visible `LibraryAsyncLogger[S]` type instead of changing the visible sink type.
|
|
- Async state helpers remain hidden behind the narrower facade after rewrapping; use `to_async_logger()` if later code needs them.
|
|
- `bind(...)` is an ergonomic alias for this same behavior.
|
|
|
|
### How to Use
|
|
|
|
Here are some specific examples provided.
|
|
|
|
#### When Need Stable Library Metadata On Every Async Record
|
|
|
|
When a package should attach fixed metadata to all queued records:
|
|
```moonbit
|
|
let logger = LibraryAsyncLogger::new(@bitlogger.console_sink())
|
|
.with_target("plugin")
|
|
.with_context_fields([
|
|
@bitlogger.field("plugin", "alpha"),
|
|
@bitlogger.field("region", "cn"),
|
|
])
|
|
```
|
|
|
|
In this example, both fields are automatically attached before every record enters the queue.
|
|
|
|
#### When Combine Async Target Scoping And Shared Fields
|
|
|
|
When a subsystem facade should carry both a target and stable context:
|
|
```moonbit
|
|
let worker = LibraryAsyncLogger::new(@bitlogger.console_sink(), target="sdk")
|
|
.child("worker")
|
|
.with_context_fields([@bitlogger.field("component", "worker")])
|
|
```
|
|
|
|
In this example, target composition and field binding stay separate but compose cleanly.
|
|
|
|
And the returned facade keeps the same underlying async runtime state while carrying a different shared field set.
|
|
|
|
### Error Case
|
|
|
|
e.g.:
|
|
- If `fields` is empty, the returned facade remains valid and simply stores an empty shared field set.
|
|
|
|
- If duplicate field keys are provided, all fields are still emitted for downstream formatting or inspection.
|
|
|
|
- If callers want to add event-specific fields without replacing the shared set, they should pass those through `log(..., fields=...)` on the returned facade.
|
|
|
|
### Notes
|
|
|
|
1. Use this for stable shared metadata, not highly dynamic event-specific values.
|
|
|
|
2. The narrower `LibraryAsyncLogger` surface is preserved after field binding.
|
|
|
|
3. Use `bind(...)` when the shorter alias reads better in chained library code.
|