Struct ChainEvent 

pub struct ChainEvent {
    pub sequence: u64,
    pub chain_id: u32,
    pub timestamp: DateTime<Utc>,
    pub prev_hash: [u8; 32],
    pub hash: [u8; 32],
    pub payload_hash: [u8; 32],
    pub source: String,
    pub kind: String,
    pub payload: Option<Value>,
    pub idempotency_key: Option<[u8; 32]>,
    pub rule_hash: Option<[u8; 32]>,
}

A chain event – one entry in the append-only log.

Fields

sequence: u64

Sequence number (0 = genesis).

chain_id: u32

Chain ID (0 = local).

timestamp: DateTime<Utc>

Event timestamp.

prev_hash: [u8; 32]

SHAKE-256 hash of the previous event (zeroed for genesis).

hash: [u8; 32]

SHAKE-256 hash of this event (covers all fields incl. payload).

payload_hash: [u8; 32]

SHAKE-256 hash of the canonical payload bytes (zeroed when payload is None). Enables independent content verification.

source: String

Event source (e.g. “kernel”, “service.cron”, “cluster”).

kind: String

Event kind (e.g. “boot”, “service.start”, “peer.join”).

payload: Option<Value>

Optional payload (JSON).

idempotency_key: Option<[u8; 32]>

Optional idempotency key for replay protection (WEFT-103).

When provided to ChainManager::append_idempotent, the chain rejects (returns the prior event without appending a duplicate) any new event whose key matches an entry within the last IDEMPOTENCY_LOOKBACK events. This shields the append path from replayed writes at retry boundaries (mesh peers, HTTP reties, sync-sweep loops).

Not covered by the event hash. Idempotency keys are an out-of-band deduplication hint, not part of the immutable chain commitment. This keeps existing chains hash-stable as the field rolls out and allows different writers to retry the same logical operation without invalidating the ledger.

rule_hash: Option<[u8; 32]>

Hash of the kind-registry rules in force when this event was appended (ADR-103 A7). None for every pre-P2 event.

Covered by the event hash only when Some, so events without it hash byte-identically to before the field existed. A binary that predates the field ignores it on read, recomputes a different hash and fails integrity verification loudly.

Trait Implementations

impl Clone for ChainEvent

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ChainEvent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ChainEvent

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for ChainEvent

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.