Crate fusee_core 

The deterministic core of Fusee.

Nothing in this crate performs I/O, reads a clock, spawns a thread or takes a lock. Each piece is a state machine driven by its host:

• record: journal records and their encodings.
• segment: the log segment format, the in-memory segment::LogWriter and the recovery scanner that tells torn tails from lost records.
• run: the per-run run::RunMachine that assigns journal positions, replays recorded results in journal order and detects nondeterminism.
• shard: shard::ShardCore, the state derived from a shard’s log: runs, timers, signals, and outputs held until their records are durable.
• wheel: the hierarchical timing wheel.
• store: run store and checkpoint formats.
• table: the compact table of every run a shard knows.
• vsr: the replication protocol as a pure state machine.
• frame: the framed binary protocol shared by replication and server mode.

Because the core is pure, the same code runs in production and inside the deterministic simulator (fusee-sim), where disks tear writes and networks drop messages under a seeded scheduler.

Re-exports

pub use record::Lsn;

pub use record::Name;

pub use record::Payload;

pub use record::Record;

pub use record::RecordBuf;

pub use record::RecordRef;

pub use record::RunId;

pub use record::Seq;

pub use record::Status;

Modules

frame

Framing for Fusee’s binary protocols (replication and server mode).

record

Journal records.

run

The per-run journal machine.

segment

Log segment format, the in-memory log writer and the recovery scanner.

shard

Shard state.

store

Formats for the run store and checkpoints.

table

The run table: one 32-byte entry for every run a shard knows, loaded or parked, found by run ID or by workflow ID hash.

vsr

Replication: a primary-backup protocol in the style of Viewstamped Replication Revisited, as a pure state machine.

wal

Log format 3: one write-ahead log per device, shared by every shard.

wheel

Hierarchical timing wheel with millisecond resolution.

wire

Little-endian integers, LEB128 varints and length-prefixed bytes.