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BitLogger/docs/api/async-logger-shutdown.md
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2026-07-17 15:53:21 +08:00

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name, group, category, update-time, description, key-word
name group category update-time description key-word
async-logger-shutdown api async 20260707 Gracefully stop an async logger by waiting for idle or clearing queued work, then waiting for any active worker to finish.
async
logger
lifecycle
public

Async-logger-shutdown

Gracefully stop an async logger. This is the main high-level shutdown API for async logging because it coordinates drain behavior, closure, and worker completion.

Interface

pub async fn[S] AsyncLogger::shutdown(self : AsyncLogger[S], clear? : Bool = false) -> Unit {}

input

  • self : AsyncLogger[S] - 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

  • clear=false first waits for idle, then closes the logger.
  • If wait_idle() returned early because a worker failure left backlog behind, shutdown now converts that retained pending backlog into dropped records with close(clear=true) before returning.
  • clear=true immediately closes and abandons pending records, even if no worker was ever started for that logger.
  • After either shutdown branch starts closing, the helper waits until is_running() becomes false before returning.
  • In lifecycle-phase terms, shutdown drives the logger into closing while a worker is still active, then settles into closed or closed_failed once that worker has exited.
  • Shutdown itself does not clear retained worker failure state. If a previous run() already recorded has_failed=true and a non-empty last_error(), those diagnostics can remain visible after shutdown completes.
  • Because clear=false delegates to wait_idle() first, shutdown can also wait indefinitely when pending records exist but no worker is making progress and no failure flag is raised.

How to Use

Here are some specific examples provided.

When Need Graceful Service Shutdown

When a service should stop logging only after queued records are drained:

logger.shutdown()

In this example, the logger waits for normal drain behavior before final closure.

When Need Fast Shutdown Under Pressure

When teardown should prefer speed over preserving backlog:

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.

  • If wait_idle() returns early because the worker failed, shutdown still finishes by converting retained pending backlog into dropped records before it returns.

  • Even after shutdown finishes with is_closed=true, callers can still observe retained has_failed() and last_error() from an earlier worker failure.

  • If pending work exists but no worker was started, shutdown(clear=false) may never reach its later close step because it is still waiting inside wait_idle().

  • 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 raw close() in normal application shutdown paths.

  2. shutdown() now always waits for an already-running worker to leave is_running=true before returning.

  3. Choose clear=true only when loss of queued records is acceptable.

  4. Pair it with state() or focused counters when tests need to assert whether shutdown drained backlog or converted it into dropped records.

  5. Prefer shutdown(clear=true) when teardown must not depend on a still-running drain worker.