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Async-logger-has-failed

Read whether the async logger worker has encountered a failure. This helper is a compact health signal for async delivery problems.

Interface

moonbit
pub fn[S] AsyncLogger::has_failed(self : AsyncLogger[S]) -> Bool {}

input

  • self : AsyncLogger[S] - Async logger whose failure flag should be inspected.

output

  • Bool - Whether the worker has failed.

Explanation

Detailed rules explaining key parameters and behaviors

  • run() clears previous failure state at startup.
  • run() also clears the stored last_error() string at startup before drain work begins.
  • If the worker loop raises an error, the logger records that failure and exposes it through this flag.
  • Once set by a failed run, the flag stays true until a later run() invocation actually starts and resets it.
  • Failure-driven shutdown does not clear this flag by itself, so has_failed() can remain true even after the logger is already closed.
  • This helper is intentionally compact and should usually be paired with last_error() for details.
  • Failure state is about runtime drain execution, not whether records were dropped due to overflow policy.

How to Use

Here are some specific examples provided.

When Need A Fast Failure Signal

When runtime diagnostics should branch on worker health:

moonbit
if logger.has_failed() {
  println(logger.last_error())
}

In this example, the code checks failure state first, then reads the error detail.

When Inspect Async Runtime State In Tests

When a test needs to confirm that drain execution stayed healthy:

moonbit
ignore(logger.has_failed())

In this example, the helper exposes a simple pass-fail runtime indicator.

Error Case

e.g.:

  • If has_failed() is false, queue pressure or dropped records may still exist for non-failure reasons.

  • If has_failed() becomes true, wait_idle() may stop early while pending records still remain until a later close or clear path handles them.

  • In the current regression coverage, that later handling can be an explicit close(clear=true) that resets pending backlog immediately or a runtime-dependent shutdown(...) path that either clears pending into dropped records or leaves the closed-queue remainder visible.

  • If has_failed() is still true after shutdown, that does not by itself mean cleanup failed; the logger may already be is_closed=true while the remaining pending-versus-dropped outcome still reflects the active runtime's shutdown path.

  • If has_failed() is true, callers should inspect last_error() or state() for more context.

  • close() or shutdown() do not clear this flag by themselves; only a later run() that has already started resets it.

Notes

  1. This helper reports worker failure, not general queue stress.

  2. Pair it with last_error() when you need actionable detail.

  3. Pair it with is_running() or state() when you also need to know whether the worker has already exited and whether backlog remains.

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