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BitLogger/docs/api/runtime-file-state.md
2026-07-17 15:53:21 +08:00

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---
name: runtime-file-state
group: api
category: runtime
update-time: 20260707
description: Public combined file-and-queue runtime state re-exported from file_model for runtime diagnostics.
key-word:
- runtime
- file
- state
- public
---
## Runtime-file-state
`RuntimeFileState` is the public snapshot object that combines file state with queue runtime context for file-backed runtime diagnostics. On the root `src` facade, it is re-exported from `src/file_model`, which is the real owner of the concrete runtime file state model.
### Interface
```moonbit
pub using @file_model { type RuntimeFileState }
```
#### output
- `RuntimeFileState` - Public combined runtime snapshot containing a `file` snapshot plus queue metadata such as `queued`, `pending_count`, and `dropped_count`.
### Explanation
Detailed rules explaining key parameters and behaviors
- This root surface is a re-export, not the concrete owner definition.
- The concrete type lives in `@file_model.RuntimeFileState`, not in `@utils`.
- The current fields are `file : FileSinkState`, `queued : Bool`, `pending_count : Int`, and `dropped_count : Int`.
- This type is returned by `RuntimeSink::file_runtime_state()` and by `ConfiguredLogger::file_runtime_state()` when file runtime context is available.
- It is broader than `FileSinkState` because it also reports whether queue wrapping is involved and how the queue is behaving.
### How to Use
Here are some specific examples provided.
#### When Need Combined File And Queue Diagnostics
When a direct runtime sink may wrap a file sink in a queue:
```moonbit
match sink.file_runtime_state() {
Some(snapshot) => println(snapshot.pending_count)
None => ()
}
```
In this example, queue backlog can be inspected alongside the embedded file state.
#### When Need A Single Exportable Runtime Snapshot
When runtime support output should include both file and queue context:
```moonbit
match sink.file_runtime_state() {
Some(snapshot) => println(stringify_runtime_file_state(snapshot, pretty=true))
None => ()
}
```
In this example, one typed object covers both the file snapshot and queue counters.
### Error Case
e.g.:
- `RuntimeFileState` itself does not have a runtime failure mode.
- If the runtime sink is not file-backed, `file_runtime_state()` may return `None` instead of producing this snapshot.
### Notes
1. Use this type when queued-file diagnostics matter, not just raw file status.
2. Use `runtime_file_state_to_json(...)` or `stringify_runtime_file_state(...)` when the snapshot should be exported.