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BitLogger/docs/api/library-async-logger-shutdown.md
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2026-06-14 00:08:24 +08:00

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---
name: library-async-logger-shutdown
group: api
category: facade
update-time: 20260614
description: Gracefully stop a LibraryAsyncLogger by draining or clearing queued work, with worker-wait behavior depending on the active async runtime.
key-word:
- async
- library
- lifecycle
- public
---
## Library-async-logger-shutdown
Gracefully stop a library-facing async logger. This is the high-level shutdown API for `LibraryAsyncLogger[S]` because it coordinates drain behavior, closure, and worker completion while preserving the narrower facade surface.
### Interface
```moonbit
pub async fn[S] LibraryAsyncLogger::shutdown(
self : LibraryAsyncLogger[S],
clear? : Bool = false,
) -> Unit {
```
#### input
- `self : LibraryAsyncLogger[S]` - Library-facing async logger that should be shut down.
- `clear : Bool` - Whether pending records should be abandoned immediately instead of waiting for idle first.
#### output
- `Unit` - No return value. The method completes after shutdown coordination finishes.
### Explanation
Detailed rules explaining key parameters and behaviors
- This method delegates directly to the wrapped async logger's `shutdown(...)` behavior.
- `clear=false` first waits for idle, then closes the logger.
- If the active async runtime uses shutdown clearing after idle and backlog still remains, the wrapped logger falls back to `close(clear=true)`.
- `clear=true` immediately closes and abandons pending records.
- In runtimes where shutdown waits for workers, the method then waits until the worker is no longer running before returning.
### How to Use
Here are some specific examples provided.
#### When Need Graceful Async Library Shutdown
When a service should stop logging only after queued records are drained:
```moonbit
await logger.shutdown()
```
In this example, the facade waits for normal drain behavior before final closure.
#### When Need Fast Shutdown Under Pressure
When teardown should prefer speed over preserving backlog:
```moonbit
await logger.shutdown(clear=true)
```
In this example, pending work is abandoned intentionally so shutdown can complete sooner.
### Error Case
e.g.:
- If `clear=true`, pending records are intentionally dropped rather than drained.
- In compatibility-style runtimes without background-worker waiting, shutdown still closes the logger but may not perform the extra wait-for-worker phase described for native-worker runtimes.
- If callers skip `shutdown()` and only inspect flags manually, it is easier to leave the worker lifecycle in an unclear state.
### Notes
1. Prefer this API over low-level closure control in normal library shutdown paths.
2. Exact post-close waiting behavior depends on the active async runtime mode.
3. Choose `clear=true` only when loss of queued records is acceptable.