Crate sim_lib_stream_fabric

Expand description

Content-addressed distributed evaluation for remote stream realization.

This crate is the EvalFabric / realize transport layer for SIM streams: the location-transparent eval surface that server and agent code target to place work and exchange streams, rather than reaching for transport-specific APIs. It turns StreamValue packet spines into kernel chunk events or existing server stream frames, and turns event or frame buffers back into lazy stream spines. It stays in library space: it does not add server frame kinds or kernel object hooks.

Content-addressed evaluation treats a fleet as a store of immutable eval replies. ContentServeFabric answers a request only if this node already holds its ContentKey. ContentAddressedFabric presents local and peer cassettes as one EvalFabric: it checks the local EvalCassette, asks peers that hold the content id, computes on a home site when no holder has the reply, and records every successful reply so this node becomes a holder too. There is no routing table; the lookup question is simply “who holds content id X.” HoldingIndex is a grow-only gossip index of holders. Because content never mutates, a holder fact is never invalidated and the index needs no consensus. Recovery is EvalCassette::from_ledger replay. The FleetRelayFabric design names the explicit-routing alternative for small, statically known fleets.

The surface has four families:

Control plane: StreamControl and its frame round-trip carry open, next, push, close, cancel, stats, metadata, and fault actions between peers.
Frame codec: stream_to_frames and the stream_frames_to_* family encode a stream into bounded server frames and decode them back, applying StreamFrameLimits.
Placement: ServerPlacementRequest and server_placement_stream_frames place a fragment on a site under PlacementResourceLimits, with sensitive inputs redacted by redact_placement_expr.
Realize requests: stream_realize_request and realize_stream_events bridge a stream to the realize event surface.
Relay surfaces: RelayFabric carries a surface session as a remote EvalFabric node. ContentKey gives each stable EvalRequest a deterministic identity, EvalCassette stores successful replies in an effect-ledger-backed cache, LedgeredRelayFabric adds cache-first cassette replay and write-through around any inner fabric, and ContentAddressedFabric resolves work from any holder by content id. Capability policy stays with the inner fabric and is not weakened by caching.

Structs§

ContentAddressedFabric: Content-addressed lookup fabric over local and peer cassettes.
ContentKey: Content-addressed identity for an EvalRequest.
ContentPeer: A peer that may hold content in its local cassette.
ContentServeFabric: Read side of the content-addressed store for one node.
EffectLedgerCassette: A kernel EffectLedger adapter for EvalCassette.
EvalCassette: An EffectLedger-backed cache of content-addressed eval replies.
HeldContent: A claim that one node holds one content id in its cassette.
HoldingIndex: A grow-only index of which nodes hold which content ids.
LedgeredRelayFabric: A cache-first EvalFabric that records successful replies in a cassette.
PlacementResourceLimits: Resource bounds enforced on a server placement before and during execution.
RelayFabric: A remote or relayed EvalFabric node carrying a surface session.
ServerPlacementRequest: Server placement request carried through stream-fabric server frames.
StreamFrameLimits: Resource bounds applied while encoding a stream into server frames.

Enums§

PlacementCapability: Capability a peer must hold to place work across the stream fabric.
RelayStatus: The connection state of a RelayFabric link.
StreamControl: Control-plane operation exchanged over remote stream-fabric frames.

Traits§

EvalCassetteLedger: Append and replay surface used by EvalCassette.

Functions§

cassette_to_stream_frames: Re-encodes a recorded StreamCassette back into server frames.
event_buffer_to_stream: Folds a buffer of run events into a pull-based StreamValue.
expr_chunk_event: Builds a chunk event whose payload is the interned data packet (kind expr).
expr_to_stream_chunk_frame: Compatibility helper. New code should call sim_lib_server::stream_chunk_frame_from_expr directly.
ledgered_relay_fabric_value: Wraps inner and cassette as an opaque runtime value.
placement_capability_names: Returns the kernel capability names for every PlacementCapability.
placement_host_device_capability: Returns the capability required to reach a host device during placement.
placement_remote_render_capability: Returns the capability required to render a fragment remotely.
placement_run_node_on_lan_peer_capability: Returns the capability required to run a placed node on a LAN peer site.
placement_run_node_on_server_capability: Returns the capability required to run a placed node on the server site.
realize_placed_stream_events: Realizes a placed fragment on site and returns its output envelopes.
realize_stream_events: Drains a stream into the events of one realized run.
redact_placement_expr: Returns a copy of expr with sensitive placement data redacted.
refused_profile_diagnostic_kind: Returns the diagnostic kind marking a transport profile refused over frames.
remote_error_diagnostic_kind: Returns the diagnostic kind marking a remote-side error surfaced locally.
remote_frame_to_event: Converts a single remote server frame into a run event, if it carries one.
server_buffered_preview_profile: Returns the server buffered-preview output profile.
server_placement_frame_operation_symbols: Returns the request, result, and refusal placement operation symbols.
server_placement_refusal_diagnostic_kind: Returns the diagnostic kind emitted when server placement is refused.
server_placement_refusal_symbol: Returns the operation symbol for a server placement refusal data frame.
server_placement_request_symbol: Returns the operation symbol for a server placement request data frame.
server_placement_result_symbol: Returns the operation symbol for a server placement result data frame.
server_placement_stream_frames: Places a fragment on the server site and encodes the exchange as frames.
server_render_return_profile: Returns the server render-return output profile.
server_site_symbol: Returns the site symbol naming the server placement target.
stream_chunk_frame_to_expr: Compatibility helper. New code should call sim_lib_server::stream_frame_to_expr directly.
stream_control_cancel_symbol: Returns the operation symbol for the cancel control action.
stream_control_close_symbol: Returns the operation symbol for the close control action.
stream_control_fault_symbol: Returns the operation symbol for the fault control action.
stream_control_frame_from_control: Encodes a StreamControl into a server stream-chunk frame.
stream_control_from_frame: Decodes a server stream-chunk frame back into a StreamControl.
stream_control_metadata_symbol: Returns the operation symbol for the metadata control action.
stream_control_next_symbol: Returns the operation symbol for the next control action.
stream_control_open_symbol: Returns the operation symbol for the open control action.
stream_control_operation_symbols: Returns every stream-fabric control operation symbol, one per variant.
stream_control_push_symbol: Returns the operation symbol for the push control action.
stream_control_required_capability: Returns the capability required to perform control.
stream_control_stats_symbol: Returns the operation symbol for the stats control action.
stream_frames_to_cassette: Decodes server frames into a replayable StreamCassette.
stream_frames_to_events: Decodes server frames into stream metadata plus a buffer of run events.
stream_frames_to_stream: Decodes a buffer of server frames back into a lazy StreamValue.
stream_limit_diagnostic_kind: Returns the diagnostic kind marking a stream truncated by a fabric limit.
stream_realize_request: Builds a realize request that observes a term as an event stream.
stream_to_frames: Encodes a stream into server frames with default envelope, profile, limits.
stream_to_frames_with_envelope: Encodes a stream into server frames under a caller-supplied frame envelope.
stream_to_frames_with_limits: Encodes a stream into server frames, enforcing every fabric resource bound.
stream_to_frames_with_profile: Encodes a stream into server frames under a caller-chosen transport profile.