tlbmc/hft_capabilities.proto

edition = "2023";

package milotic_hft;

import "identifier.proto";
import "subscription_params.proto";

message GetCapabilitiesRequest {
  // ETag-style revalidation. If the service's current generation matches,
  // the response carries unchanged=TRISTATE_TRUE and an empty body.
  string known_generation = 1;
}

// One per hft service.
message CapabilitiesResponse {
  // Opaque per-boot identifier. Generated once on HFT service startup (e.g.
  // UUID4) and held constant until the next service restart. Used by collectors
  // as an ETag.
  //
  // The contract is "capabilities cannot change without a service restart," so
  // a matching `generation` is sufficient evidence that the cache is valid.
  string generation = 1;

  // TRISTATE_TRUE if the request's known_generation matched and the rest of
  // this response was elided. Collector keeps its cache.
  Tristate unchanged = 2;

  // Service features.
  ServiceFeatures features = 3;

  // ---- Identifier-level capabilities (static) ----
  // Per-identifier dynamic state (present/missing/stale) flows in-band on
  // the data stream via sensor_payload.State and is NOT included here.
  repeated IdentifierDescriptor identifier_descriptors = 4;
}

enum Tristate {
  TRISTATE_UNSPECIFIED = 0;
  TRISTATE_TRUE = 1;
  TRISTATE_FALSE = 2;
}

message ServiceFeatures {
  // Whether the service supports edge filtering at the source. If
  // TRISTATE_FALSE, edge_filtering_detail will not be populated.
  Tristate edge_filtering_supported = 1;

  // Detail capabilities for specific edge filtering types.
  message EdgeFilteringDetail {
    // Whether the service supports the ON-CHANGE filter.
    Tristate on_change_supported = 1;
    // Whether the service supports the SDT (Swinging Door Trending) filter.
    Tristate sdt_supported = 2;
  }
  EdgeFilteringDetail edge_filtering_detail = 2;
}

message SubscriptionShape {
  SubscriptionPolicy.ConfigurationType configuration_type = 1;
  SubscriptionPolicy.ResourceType resource_type = 2;
}

message IdentifierDescriptor {
  Identifier identifier = 1;

  // Best-effort upstream cadence. Absent (zero) means unknown to hft service.
  uint32 source_sampling_interval_ms = 2;

  // Reading type. Mirrors HighFrequencySensorReading.oneof.
  enum ReadingType {
    READING_TYPE_UNSPECIFIED = 0;
    FLOAT = 1;
    COUNT = 2;
    FRU = 3;
  }
  ReadingType reading_type = 3;
}