syntax = "proto3";

package envoy.service.metrics.v2;

option java_outer_classname = "MetricsServiceProto";
option java_multiple_files = true;
option java_package = "io.envoyproxy.envoy.service.metrics.v2";
option go_package = "v2";
option java_generic_services = true;

import "envoy/api/v2/core/base.proto";

// This line is different from the definition in https://github.com/envoyproxy/data-plane-api to let
// the dependency structure clearer.
import "prometheus/client_model/metrics.proto";

import "validate/validate.proto";

// Service for streaming metrics to server that consumes the metrics data. It uses Prometheus metric
// data model as a standard to represent metrics information.
service MetricsService {
  // Envoy will connect and send StreamMetricsMessage messages forever. It does not expect any
  // response to be sent as nothing would be done in the case of failure.
  rpc StreamMetrics(stream StreamMetricsMessage) returns (StreamMetricsResponse) {
  }
}

message StreamMetricsResponse {
}

message StreamMetricsMessage {
  message Identifier {
    // The node sending metrics over the stream.
    envoy.api.v2.core.Node node = 1 [(validate.rules).message.required = true];
  }

  // Identifier data effectively is a structured metadata. As a performance optimization this will
  // only be sent in the first message on the stream.
  Identifier identifier = 1;

  // A list of metric entries
  repeated io.prometheus.client.MetricFamily envoy_metrics = 2;
}