Files
BitLogger/docs/api/library-logger-error.md
T
2026-06-13 20:42:12 +08:00

81 lines
2.3 KiB
Markdown

---
name: library-logger-error
group: api
category: facade
update-time: 20260613
description: Emit an error-level record through a LibraryLogger facade using the highest built-in severity shortcut.
key-word:
- library
- facade
- error
- public
---
## Library-logger-error
Emit an error-level record through the library-facing sync logger. This is the convenience wrapper for `log(Level::Error, ...)` on `LibraryLogger[S]`.
### Interface
```moonbit
pub fn[S : Sink] LibraryLogger::error(
self : LibraryLogger[S],
message : String,
fields~ : Array[Field] = [],
) -> Unit {
```
#### input
- `self : LibraryLogger[S]` - Library-facing logger that should emit the error record.
- `message : String` - Error message text.
- `fields : Array[Field]` - Optional structured fields attached to the record.
#### output
- `Unit` - No return value. The record is handled according to the current threshold and wrapped sink pipeline.
### Explanation
Detailed rules explaining key parameters and behaviors
- This helper delegates to `log(Level::Error, ...)` on the wrapped logger.
- `Error` is the highest built-in severity in this sync facade API.
- Per-call target override is not exposed here; use `log(...)` when explicit target control is required.
- Sink composition, filtering, patching, and queue wrappers still apply normally.
### How to Use
Here are some specific examples provided.
#### When Report A Failing Library Operation
When an operation should emit a high-severity failure event:
```moonbit
logger.error("worker execution failed")
```
In this example, the call site clearly communicates failure severity.
#### When Attach Structured Error Context
When an error event should include diagnostic fields:
```moonbit
logger.error("dispatch failed", fields=[field("job_id", "42")])
```
In this example, the record carries machine-readable context without dropping to the generic `log(...)` form.
### Error Case
e.g.:
- If the logger minimum level is above `Error`, the call still returns without writing, though this configuration is unusual.
- If a target override is required, use `log(...)` instead of this severity shortcut.
### Notes
1. Use this helper for high-severity library failures.
2. Emitting an error record is separate from throwing or handling program exceptions.