Struct EventEnvelope 

pub struct EventEnvelope {
    pub seq: u64,
    pub timestamp_us: i64,
    pub realm: String,
    pub namespace: String,
    pub agent_id: String,
    pub event: MemoryEvent,
    pub hmac: Option<String>,
}

A durable event wrapper with monotonic sequence number and metadata.

Envelopes are stored in the events LanceDB dataset for replay, audit, and streaming.

When a realm secret is configured, each envelope carries an HMAC-SHA256 tag computed over the bincode-serialized payload. This enables tamper detection on audit events.

Fields

seq: u64

Monotonically increasing sequence number (gap-free per writer).

timestamp_us: i64

Wall-clock microsecond timestamp.

realm: String

Realm (tenant) isolation.

namespace: String

Namespace within the realm.

agent_id: String

Agent that triggered the mutation.

event: MemoryEvent

The actual event payload.

hmac: Option<String>

HMAC-SHA256 tag for tamper detection (hex-encoded). None when no realm secret is configured.

Implementations

impl EventEnvelope

pub fn new( seq: u64, realm: impl Into<String>, namespace: impl Into<String>, agent_id: impl Into<String>, event: MemoryEvent, ) -> Self

Create a new envelope with the given metadata.

pub fn sign(&mut self, secret: &[u8])

Compute and attach an HMAC-SHA256 tag using the given secret.

The HMAC is computed over the bincode-serialized event payload concatenated with the envelope metadata (seq, timestamp, realm, namespace, agent_id). This ensures any tampering with the envelope is detectable.

pub fn verify_hmac(&self, secret: &[u8]) -> bool

Verify the HMAC tag against the given secret.

Returns true if the HMAC matches, false if tampered or missing.

pub fn event_type(&self) -> &'static str

Event type string (delegates to inner event).

pub fn bincode_size(&self) -> usize

Byte size of the bincode-serialized envelope (for size budgeting).

Trait Implementations

impl Clone for EventEnvelope

fn clone(&self) -> EventEnvelope

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EventEnvelope

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for EventEnvelope

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for EventEnvelope

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

where __S: Serializer,

Serialize this value into the given Serde serializer.