✨ Add file sink state snapshots

bitlogger/BitLogger_test.mbt

@@ -206,8 +206,13 @@ test "configured logger exposes file sink observability helpers" {
       ),
     ),
   )
+  let state = logger.file_state()
   inspect(logger.file_available() == native_files_supported(), content="true")
   inspect(logger.file_path(), content="config-file.log")
+  inspect(state.path, content="config-file.log")
+  inspect(state.available == logger.file_available(), content="true")
+  inspect(state.append == logger.file_append_mode(), content="true")
+  inspect(state.auto_flush == logger.file_auto_flush(), content="true")
   inspect(logger.file_append_mode(), content="true")
   inspect(logger.file_auto_flush(), content="false")
   inspect(logger.file_rotation_enabled(), content="true")
@@ -264,6 +269,10 @@ test "configured logger file setters update file sink policy state" {
   inspect(logger.file_rotation_config() is None, content="true")
   inspect(logger.file_reopen(), content=if logger.file_available() { "true" } else { "false" })
   inspect(logger.file_append_mode(), content="false")
+  let state = logger.file_state()
+  inspect(state.append, content="false")
+  inspect(state.auto_flush, content="false")
+  inspect(state.rotation is None, content="true")
   ignore(logger.close())
 }
 

bitlogger/BitLogger_wbtest.mbt

@@ -89,8 +89,14 @@ test "native file support flag is queryable" {
 
 test "file sink availability reflects backend support" {
   let sink = file_sink("bitlogger-test.log")
+  let state = sink.state()
   inspect(sink.path(), content="bitlogger-test.log")
   inspect(sink.is_available() == native_files_supported(), content="true")
+  inspect(state.path, content="bitlogger-test.log")
+  inspect(state.available == sink.is_available(), content="true")
+  inspect(state.append == sink.append_mode(), content="true")
+  inspect(state.auto_flush == sink.auto_flush_enabled(), content="true")
+  inspect((state.rotation is None) == (sink.rotation_config() is None), content="true")
   inspect(sink.append_mode(), content="true")
   inspect(sink.auto_flush_enabled(), content="true")
   inspect(sink.rotation_enabled(), content="false")
@@ -145,6 +151,10 @@ test "file sink setters update auto flush and rotation state" {
   inspect(sink.rotation_config() is None, content="true")
   inspect(sink.reopen(), content=if sink.is_available() { "true" } else { "false" })
   inspect(sink.append_mode(), content="false")
+  let state = sink.state()
+  inspect(state.append, content="false")
+  inspect(state.auto_flush, content="false")
+  inspect(state.rotation is None, content="true")
 }
 
 test "file sink tracks rotation failures on unavailable backend" {

bitlogger/README.mbt.md

@@ -225,7 +225,8 @@ test {
 - `set_append_mode(...)` updates the stored append policy without forcing an immediate reopen / `set_append_mode(...)` 可直接更新保存的 append 策略，但不会强制立即 reopen
 - `path()` and `auto_flush_enabled()` expose core file sink policy state / `path()` 与 `auto_flush_enabled()` 可读取 file sink 的基础策略状态
 - `rotation_enabled()` and `rotation_config()` expose whether rotation is active and which settings are currently applied / `rotation_enabled()` 与 `rotation_config()` 可读取 rotation 是否启用及当前配置参数
+- `state()` exposes a single file-sink snapshot including path, availability, append policy, auto-flush, rotation config, and failure counters / `state()` 可一次性读取包含 path、availability、append、auto-flush、rotation 配置与失败计数的 file sink 快照
 - `set_auto_flush(...)`, `set_rotation(...)`, and `clear_rotation()` allow runtime tuning of core file sink policies / `set_auto_flush(...)`、`set_rotation(...)`、`clear_rotation()` 可在运行期调整 file sink 的基础策略
 - `open_failures()`、`write_failures()`、`flush_failures()`、`rotation_failures()` expose basic sink health counters / `open_failures()`、`write_failures()`、`flush_failures()`、`rotation_failures()` 可用于观察基础 sink 健康状态
-- `ConfiguredLogger` also forwards file reopen, flush, close, append-mode, path, auto-flush, rotation-config, append setter, policy setter, and failure-counter helpers for config-built file sinks / `ConfiguredLogger` 也会为配置生成的 file sink 转发 reopen、flush、close、append-mode、path、auto-flush、rotation 配置、append setter、策略 setter 与失败计数访问器
+- `ConfiguredLogger` also forwards file reopen, flush, close, append-mode, path, auto-flush, rotation-config, state snapshot, append setter, policy setter, and failure-counter helpers for config-built file sinks / `ConfiguredLogger` 也会为配置生成的 file sink 转发 reopen、flush、close、append-mode、path、auto-flush、rotation 配置、state 快照、append setter、策略 setter 与失败计数访问器
 - current scope is observability-first, not a full self-healing sink runtime / 当前定位仍以可观测性优先，不是完整自愈型 sink runtime

bitlogger/config.mbt

@@ -405,6 +405,24 @@ pub fn RuntimeSink::file_rotation_failures(self : RuntimeSink) -> Int {
   }
 }
 
+pub fn RuntimeSink::file_state(self : RuntimeSink) -> FileSinkState {
+  match self {
+    File(sink) => sink.state()
+    QueuedFile(sink) => sink.sink.state()
+    _ => {
+      path: "",
+      available: false,
+      append: false,
+      auto_flush: false,
+      rotation: None,
+      open_failures: 0,
+      write_failures: 0,
+      flush_failures: 0,
+      rotation_failures: 0,
+    }
+  }
+}
+
 pub type ConfiguredLogger = Logger[RuntimeSink]
 
 pub fn ConfiguredLogger::flush(self : ConfiguredLogger) -> Int {
@@ -510,6 +528,10 @@ pub fn ConfiguredLogger::file_rotation_failures(self : ConfiguredLogger) -> Int
   self.sink.file_rotation_failures()
 }
 
+pub fn ConfiguredLogger::file_state(self : ConfiguredLogger) -> FileSinkState {
+  self.sink.file_state()
+}
+
 fn expect_object(
   value : @json_parser.JsonValue,
   context : String,

bitlogger/sinks.mbt

@@ -62,6 +62,18 @@ pub struct FileRotation {
   max_backups : Int
 }
 
+pub struct FileSinkState {
+  path : String
+  available : Bool
+  append : Bool
+  auto_flush : Bool
+  rotation : FileRotation?
+  open_failures : Int
+  write_failures : Int
+  flush_failures : Int
+  rotation_failures : Int
+}
+
 pub fn file_rotation(max_bytes : Int, max_backups~ : Int = 1) -> FileRotation {
   {
     max_bytes: if max_bytes <= 0 { 1 } else { max_bytes },
@@ -177,6 +189,20 @@ pub fn FileSink::flush_failures(self : FileSink) -> Int {
   self.flush_failures.val
 }
 
+pub fn FileSink::state(self : FileSink) -> FileSinkState {
+  {
+    path: self.path,
+    available: self.is_available(),
+    append: self.append.val,
+    auto_flush: self.auto_flush.val,
+    rotation: self.rotation.val,
+    open_failures: self.open_failures.val,
+    write_failures: self.write_failures.val,
+    flush_failures: self.flush_failures.val,
+    rotation_failures: self.rotation_failures.val,
+  }
+}
+
 pub fn FileSink::reopen(self : FileSink, append~ : Bool? = None) -> Bool {
   let append_mode = append.unwrap_or(self.append.val)
   self.append.val = append_mode