Struct MessageEnvelope 

pub struct MessageEnvelope {
    pub header: MessageHeader,
    pub payload: Vec<u8>,
    pub provenance: Option<ProvenanceHeader>,
    pub tenant_id: TenantId,
    pub audit_tag: AuditTag,
}

Envelope containing header and serialized payload.

The optional provenance slot carries PROV-O attribution metadata for NSAI reasoning chains (see crate::provenance). When None, the field is a single discriminant byte - zero cost for the common case. When populated, it adds a fixed-size ProvenanceHeader (see that type for size details).

The tenant_id field is the primary multi-tenant isolation key — it defaults to 0 (the unspecified tenant) which preserves single-tenant fast-path behavior and is free of HashMap lookups in the K2K broker.

The audit_tag field carries billable-unit attribution (org_id + engagement_id) and defaults to AuditTag::default (both fields zero). The K2K broker stamps the sender’s tag into outgoing envelopes when the caller leaves this as the default.

Neither the provenance, tenant_id, nor audit_tag fields are included in the legacy MessageEnvelope::to_bytes / MessageEnvelope::from_bytes wire format, which is defined by MessageHeader + raw payload for backwards compatibility. These travel separately (e.g. as part of rkyv-encoded envelope transfer on GPU) or are reattached by the router.

Fields

header: MessageHeader

Message header.

payload: Vec<u8>

Serialized payload.

provenance: Option<ProvenanceHeader>

Optional PROV-O attribution metadata. Defaults to None; only populated when the message participates in an audited reasoning chain (e.g. VynGraph NSAI pipelines).

tenant_id: TenantId

Multi-tenant isolation key. Defaults to 0 (unspecified tenant), matching single-tenant deployments that never opt in to isolation.

audit_tag: AuditTag

Billable-unit attribution: {org_id, engagement_id}. Defaults to AuditTag::default() (both fields zero). The K2K broker stamps the sending kernel’s tag into envelopes whose tag is still the default.

Implementations

impl MessageEnvelope

pub fn new<M: RingMessage>( message: &M, source_kernel: u64, dest_kernel: u64, timestamp: HlcTimestamp, ) -> Self

Create a new envelope from a message.

pub fn total_size(&self) -> usize

Get total size (header + payload).

pub fn to_bytes(&self) -> Vec<u8>

Serialize to contiguous bytes.

NOTE: the provenance metadata is intentionally not serialised here. This method keeps the historical wire format unchanged; provenance is transported out-of-band or via rkyv-encoded transfer.

pub fn from_bytes(bytes: &[u8]) -> Result<Self>

Deserialize from bytes.

Reconstructs an envelope with provenance: None and default tenant/audit fields. Callers that need provenance must reattach it via MessageEnvelope::with_provenance; callers that need tenant attribution must stamp it via MessageEnvelope::with_tenant_id / MessageEnvelope::with_audit_tag.

pub fn empty( source_kernel: u64, dest_kernel: u64, timestamp: HlcTimestamp, ) -> Self

Create an empty envelope (for testing).

pub fn with_provenance(self, provenance: ProvenanceHeader) -> Self

Attach a PROV-O provenance header (builder-style).

pub fn without_provenance(self) -> Self

Strip provenance (builder-style). Useful when routing a message into an untrusted tenant boundary where attribution must not leak.

pub fn with_tenant_id(self, tenant_id: TenantId) -> Self

Stamp the envelope with a tenant ID (builder-style).

In the two-tier tenancy model the tenant ID is the primary isolation key; the K2K broker uses it to route the message into the correct per-tenant sub-broker. Defaults to 0 (unspecified tenant).

pub fn with_audit_tag(self, audit_tag: AuditTag) -> Self

Attach an audit tag (builder-style).

The audit tag carries billable-unit attribution (org_id + engagement_id). The K2K broker preserves this tag across delivery so downstream cost accounting can attribute GPU-seconds back to the specific engagement.

Trait Implementations

impl Clone for MessageEnvelope

fn clone(&self) -> MessageEnvelope

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MessageEnvelope

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

Formats the value using the given formatter.

impl Default for MessageEnvelope

fn default() -> Self

Returns the “default value” for a type.