Hare
d5fcbc2125
- Type/Function/Variantを Segment* 系へ統一 - SessionId/SessionStart/SessionOrigin/SessionStartState/SessionState/SessionLogSink/SessionLockInfo - new_session_id / session_id / create_session* / list_sessions / lookup_session / update_session / find_by_session - protocol Event::SessionRotated → SegmentRotated、CompactDone.new_session_id → new_segment_id - Module: session_log → segment_log / session → segment (file mv 含む) pod 側の session_log_sink → segment_log_sink も同様 - crate 名 (session-store)、CLI flag (--session)、ResumeWithSession (CLI tied) は据え置き - session-tests/session_metrics_test 等の Store impl も追従
66 lines
2.6 KiB
Rust
66 lines
2.6 KiB
Rust
//! Persistence backend abstraction.
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//!
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//! [`Store`] defines the sync interface for reading and writing segment logs.
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//! Implementations handle the physical storage (filesystem, database, etc.).
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//!
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//! Sync (rather than async) is intentional: a segment log append is a single
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//! `< 1 KiB` line on local fs and completes well below a millisecond. Going
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//! through `tokio::fs` would force every caller — including `Worker`'s sync
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//! `on_history_append` callback — to bridge sync → async via a channel +
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//! drain task. Keeping the store sync lets the worker callback, Pod commit
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//! paths, and `PodInterceptor` all share one direct `append_entry` call.
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use crate::SegmentId;
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use crate::event_trace::TraceEntry;
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use crate::segment_log::LogEntry;
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/// Errors from the persistence store.
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#[derive(Debug, thiserror::Error)]
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pub enum StoreError {
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#[error("I/O error: {0}")]
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Io(#[from] std::io::Error),
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#[error("serialization error: {0}")]
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Serde(#[from] serde_json::Error),
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#[error("segment not found: {0}")]
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NotFound(SegmentId),
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#[error("log corrupted at line {line}: {message}")]
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Corrupt { line: usize, message: String },
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}
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/// Sync persistence backend for segment logs.
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///
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/// All methods take `&self` — implementations should use interior mutability
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/// (e.g., append-mode file handles) when needed.
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pub trait Store: Send + Sync {
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/// Append a single log entry to the segment log.
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///
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/// One line per call. The kernel orders concurrent `O_APPEND` writes
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/// for lines < `PIPE_BUF`, so user-space serialization is unnecessary.
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fn append(&self, id: SegmentId, entry: &LogEntry) -> Result<(), StoreError>;
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/// Read all log entries for a segment, in order.
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fn read_all(&self, id: SegmentId) -> Result<Vec<LogEntry>, StoreError>;
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/// List all segment IDs, most recent first.
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fn list_segments(&self) -> Result<Vec<SegmentId>, StoreError>;
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/// Create a new segment with initial entries.
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fn create_segment(&self, id: SegmentId, entries: &[LogEntry]) -> Result<(), StoreError>;
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/// Check if a segment exists.
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fn exists(&self, id: SegmentId) -> Result<bool, StoreError>;
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/// Count entries currently stored for a segment.
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///
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/// Used by `ensure_head_or_fork` to detect concurrent writers:
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/// if the on-disk count exceeds the writer's own append tally,
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/// another process has extended the log.
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fn read_entry_count(&self, id: SegmentId) -> Result<usize, StoreError>;
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/// Append a trace entry to the debug event trace file.
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fn append_trace(&self, id: SegmentId, entry: &TraceEntry) -> Result<(), StoreError>;
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}
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