Add gRPC query service with OTLP model

proto/api_v3/query_service.proto

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+// Copyright (c) 2021 The Jaeger Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax="proto3";
+
+package jaeger.api_v3;
+
+import "opentelemetry/proto/trace/v1/trace.proto";
+import "google/protobuf/timestamp.proto";
+import "google/protobuf/duration.proto";
+
+option go_package = "api_v3";
+option java_package = "io.jaegertracing.api_v3";
+
+// Request object to get a trace.
+message GetTraceRequest {
+  // Hex encoded 64 or 128 bit trace ID.
+  string trace_id = 1;
+}
+
+// A single response chunk holds spans from a single trace.
+message SpansResponseChunk {
+  // A list of OpenTelemetry ResourceSpans.
+  // In case of JSON format the ids (trace_id, span_id, parent_id) are encoded in base64 even though OpenTelemetry specification
+  // mandates to use hex encoding [2].
+  // Base64 is chosen to keep compatibility with JSONPb codec.
+  // [1]: https://github.com/open-telemetry/opentelemetry-proto/blob/main/opentelemetry/proto/trace/v1/trace.proto
+  // [2]: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/otlp.md#otlphttp
+  repeated opentelemetry.proto.trace.v1.ResourceSpans resource_spans = 1;
+}
+
+// Query parameters to find traces.
+// Note that some storage implementations do not guarantee correct implementation of all parameters.
+message TraceQueryParameters {
+  string service_name = 1;
+  string operation_name = 2;
+  // Attributes are matched against Span and Resource attributes.
+  // At least one span in a trace must match all specified attributes.
+  map<string, string> attributes = 3;
+  // Span min start time.
+  google.protobuf.Timestamp start_time_min = 4;
+  // Span max start time.
+  google.protobuf.Timestamp start_time_max = 5;
+  // Span min duration.
+  google.protobuf.Duration duration_min = 6;
+  // Span max duration.
+  google.protobuf.Duration duration_max = 7;
+  // Maximum number of traces in the response.
+  int32 num_traces = 8;
+}
+
+// Request object to search traces.
+message FindTracesRequest {
+  TraceQueryParameters query = 1;
+}
+
+// Request object to get service names.
+message GetServicesRequest {}
+
+// Response object to get service names.
+message GetServicesResponse {
+  repeated string services = 1;
+}
+
+// Request object to get operation names.
+message GetOperationsRequest {
+  // Required service name.
+  string service = 1;
+  // Optional span kind.
+  string span_kind = 2;
+}
+
+// Operation encapsulates information about operation.
+message Operation {
+  string name = 1;
+  string span_kind = 2;
+}
+
+// Response object to get operation names.
+message GetOperationsResponse {
+  repeated Operation operations = 1;
+}
+
+service QueryService {
+  // GetTrace returns a single trace.
+  // Note that the JSON response over HTTP is wrapped into result envelope "{"result": ...}"
+  // It means that the JSON response cannot be directly unmarshalled using JSONPb.
+  // This can be fixed by first parsing into user-defined envelope with standard JSON library
+  // or string manipulation to remove the envelope. Alternatively generate objects using OpenAPI.
+  rpc GetTrace(GetTraceRequest) returns (stream SpansResponseChunk) {}
+
+  // FindTraces searches for traces.
+  // See GetTrace for JSON unmarshalling.
+  rpc FindTraces(FindTracesRequest) returns (stream SpansResponseChunk) {}
+
+  // GetServices returns service names.
+  rpc GetServices(GetServicesRequest) returns (GetServicesResponse) {}
+
+  // GetOperations returns operation names.
+  rpc GetOperations(GetOperationsRequest) returns (GetOperationsResponse) {}
+}

proto/api_v3/query_service_http.yaml

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+# This is an API configuration to generate an HTTP/JSON -> gRPC gateway for the
+# OpenTelemetry service using github.com/grpc-ecosystem/grpc-gateway.
+type: google.api.Service
+config_version: 3
+http:
+  rules:
+    - selector: jaeger.api_v3.QueryService.GetTrace
+      get: /v3/traces/{trace_id}
+    - selector: jaeger.api_v3.QueryService.GetTraces
+      get: /v3/traces
+    - selector: jaeger.api_v3.QueryService.GetServices
+      get: /v3/services
+    - selector: jaeger.api_v3.QueryService.GetOperations
+      get: /v3/operations