duron.log module
Bases: TypedDict
Bases: Protocol
Protocol for persistent storage of operation logs.
The lease mechanism ensures exclusive access for appending entries, preventing concurrent writes from multiple processes.
async
Acquire an exclusive lease for appending to the log.
Returns:
-
bytes–Opaque lease token to be used in append() and release_lease() calls.
Raises:
-
Exception–if lease cannot be acquired (e.g., already held by another process).
Note
Leases provide concurrency control to ensure only one invoke can append to a log at a time, preventing interleaved writes from multiple processes.
async
Append a new entry to the log.
Parameters:
-
lease(bytes) –Valid lease token from acquire_lease().
-
entry(Entry) –Log entry to append (promise/create, promise/complete, stream/emit, etc).
Returns:
-
int–Log index of the appended entry.
Raises:
-
Exception–if lease is invalid or expired.
Note
Appends must be atomic and durable. The returned index must be monotonically increasing and consistent with stream() output.
async
Release a previously acquired lease.
Parameters:
-
lease(bytes) –Lease token returned by acquire_lease().
Note
Should be called when invoke completes or encounters an error. Implementations should be idempotent.
Stream log entries from storage.
Yields:
-
AsyncGenerator[tuple[int, BaseEntry], None]–Tuple of (log_index, entry) for each log entry in order.
Note
Log indices are monotonically increasing but may have gaps.