Prediction Proto Buffer Spec

Seldon Core uses REST and gRPC APIs exposed externally for business applications to connect to and also internally for microservices to implement models, routers, combiners and transformers.

• External Prediction API

  • Read this if you want to connect external business applications

• Internal Prediction API

  • Read this if you want to build a microservice to wrap a model or build another type of component such as a router, combiner or transformer

Proto Buffer and gRPC Definition

The proto file can be found here and is reproduced below:

syntax = "proto3";

import "google/protobuf/any.proto";
import "google/protobuf/struct.proto";
import "google/protobuf/empty.proto";
import "tensorflow/core/framework/tensor.proto";

package seldon.protos;

option java_package = "io.seldon.protos";
option java_outer_classname = "PredictionProtos";
option go_package = "github.com/seldonio/seldon-core/incubating/wrappers/s2i/go/pkg/api";

// [START Messages]

message SeldonMessage {

  Status status = 1;
  Meta meta = 2;
  oneof data_oneof {
    DefaultData data = 3;
    bytes binData = 4;
    string strData = 5;
    google.protobuf.Value jsonData = 6;
    google.protobuf.Any customData = 7;
  }
}

message DefaultData {
  repeated string names = 1;
  oneof data_oneof {
    Tensor tensor = 2;
    google.protobuf.ListValue ndarray = 3;
    tensorflow.TensorProto tftensor = 4;
  }
}

message Tensor {
  repeated int32 shape = 1 [packed=true];
  repeated double values = 2 [packed=true];
}

message Meta {
  string puid = 1;
  map<string,google.protobuf.Value> tags = 2;
  map<string,int32> routing = 3;
  map<string,string> requestPath = 4;
  repeated Metric metrics = 5;
}

message Metric {
 enum MetricType {
     COUNTER = 0;
     GAUGE = 1;
     TIMER = 2;
 }
 string key = 1;
 MetricType type = 2;
 float value = 3;
 map<string,string> tags = 4;
}

message SeldonMessageList {
  repeated SeldonMessage seldonMessages = 1;
}

message Status {

    enum StatusFlag {
        SUCCESS = 0;
        FAILURE = 1;
    }

    int32 code = 1;
    string info = 2;
    string reason = 3;
    StatusFlag status = 4;
}

message Feedback {
  SeldonMessage request = 1;
  SeldonMessage response = 2;
  float reward = 3;
  SeldonMessage truth = 4;
}

message RequestResponse {
  SeldonMessage request = 1;
  SeldonMessage response = 2;
}


message SeldonModelMetadataRequest
{
  string name = 1;
}


message SeldonMessageMetadata
{
  // SeldonMessage Metadata fields
  string messagetype = 1;
  google.protobuf.Value schema = 2;

  // v2 tensor metadata fields
  string name = 3;
  string datatype = 4;
  repeated int64 shape = 5;
}


message SeldonModelMetadata
{
  string name = 1;
  repeated string versions = 2;
  string platform = 3;
  repeated SeldonMessageMetadata inputs = 4;
  repeated SeldonMessageMetadata outputs = 5;
}


message SeldonGraphMetadata
{
  string name = 1;
  map<string, SeldonModelMetadata> models = 2;

  repeated SeldonMessageMetadata inputs = 3;
  repeated SeldonMessageMetadata outputs = 4;
}

// [END Messages]


// [START Services]

service Generic {
  rpc TransformInput(SeldonMessage) returns (SeldonMessage) {};
  rpc TransformOutput(SeldonMessage) returns (SeldonMessage) {};
  rpc Route(SeldonMessage) returns (SeldonMessage) {};
  rpc Aggregate(SeldonMessageList) returns (SeldonMessage) {};
  rpc SendFeedback(Feedback) returns (SeldonMessage) {};
}

service Model {
  rpc Predict(SeldonMessage) returns (SeldonMessage) {};
  rpc SendFeedback(Feedback) returns (SeldonMessage) {};
  rpc Metadata(google.protobuf.Empty) returns (SeldonModelMetadata) {};
}

service Router {
  rpc Route(SeldonMessage) returns (SeldonMessage) {};
  rpc SendFeedback(Feedback) returns (SeldonMessage) {};
}

service Transformer {
  rpc TransformInput(SeldonMessage) returns (SeldonMessage) {};
}

service OutputTransformer {
  rpc TransformOutput(SeldonMessage) returns (SeldonMessage) {};
}

service Combiner {
  rpc Aggregate(SeldonMessageList) returns (SeldonMessage) {};
}


service Seldon {
  rpc Predict(SeldonMessage) returns (SeldonMessage) {};
  rpc SendFeedback(Feedback) returns (SeldonMessage) {};
  rpc ModelMetadata(SeldonModelMetadataRequest) returns (SeldonModelMetadata) {};
  rpc GraphMetadata(google.protobuf.Empty) returns (SeldonGraphMetadata) {};
}

// [END Services]