[remote-storage][v2] Add complete IDL for trace storage (#6737)

## Which problem is this PR solving?
- Towards #6629 

## Description of the changes
- This PR completes out the interface in `trace_storage.proto` by adding
the remaining `FindTraces` and `FindTraceIDs` RPCs for the `TraceReader`
service, along with the `Export` rpc for the `TraceWriter` service.

## How was this change tested?
- CI

## Checklist
- [x] I have read
https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
- [x] I have signed all commits
- [x] I have added unit tests for the new functionality
- [x] I have run lint and test steps successfully
  - for `jaeger`: `make lint test`
  - for `jaeger-ui`: `npm run lint` and `npm run test`

---------

Signed-off-by: Mahad Zaryab <[email protected]>

internal/storage/v2/grpc/trace_storage.proto

@@ -3,7 +3,9 @@ syntax = "proto3";
 package jaeger.storage.v2;
 
 import "gogoproto/gogo.proto";
+import "google/protobuf/duration.proto";
 import "google/protobuf/timestamp.proto";
+import "opentelemetry/proto/common/v1/common.proto";
 import "opentelemetry/proto/trace/v1/trace.proto";
 
 option go_package = "storage";
@@ -62,6 +64,49 @@ message GetOperationsResponse {
   repeated Operation operations = 1;
 }
 
+// TraceQueryParameters contains query paramters to find traces. For a detailed
+// definition of each field in this message, refer to `TraceQueryParameters` in `jaeger.api_v3`
+// (https://github.com/jaegertracing/jaeger-idl/blob/main/proto/api_v3/query_service.proto).
+message TraceQueryParameters {
+  string service_name = 1;
+  string operation_name = 2;
+  repeated opentelemetry.proto.common.v1.KeyValue attributes = 3;
+  google.protobuf.Timestamp start_time_min = 4 [
+    (gogoproto.stdtime) = true,
+    (gogoproto.nullable) = false
+  ];
+  google.protobuf.Timestamp start_time_max = 5 [
+    (gogoproto.stdtime) = true,
+    (gogoproto.nullable) = false
+  ];
+  google.protobuf.Duration duration_min = 6 [
+    (gogoproto.stdduration) = true,
+    (gogoproto.nullable) = false
+  ];
+  google.protobuf.Duration duration_max = 7 [
+    (gogoproto.stdduration) = true,
+    (gogoproto.nullable) = false
+  ];
+  int32 search_depth = 8;
+}
+
+// FindTracesRequest represents a request to find traces.
+// It can be used to retrieve the traces (FindTraces) or simply
+// the trace IDs (FindTraceIDs).
+message FindTracesRequest {
+  TraceQueryParameters query = 1;
+}
+
+// FindTraceIDsResponse represents the response for FindTracesRequest.
+message FindTraceIDsResponse {
+  repeated bytes trace_ids = 1;
+}
+
+// TraceReader is a service that allows reading traces from storage.
+// Note that if you implement this service, you should also implement
+// OTEL's TraceService in package opentelemetry.proto.collector.trace.v1
+// to allow pushing traces to the storage backend
+// (https://github.com/open-telemetry/opentelemetry-proto/blob/main/opentelemetry/proto/collector/trace/v1/trace_service.proto)
 service TraceReader {
   // GetTraces returns a stream that retrieves all traces with given IDs.
   //
@@ -73,7 +118,6 @@ service TraceReader {
   // Edge cases:
   // - If no spans are found for any given trace ID, the ID is ignored.
   // - If none of the trace IDs are found in the storage, an empty response is returned.
-  // - If an error is encountered, the stream returns the error and stops.
   rpc GetTraces(GetTracesRequest) returns (stream opentelemetry.proto.trace.v1.TracesData) {}
 
   // GetServices returns all service names known to the backend from traces
@@ -83,4 +127,21 @@ service TraceReader {
   // GetOperations returns all operation names for a given service
   // known to the backend from traces within its retention period.
   rpc GetOperations(GetOperationsRequest) returns (GetOperationsResponse) {}
+
+  // FindTraces returns a stream that retrieves traces matching query parameters.
+  //
+  // The chunking rules are the same as for GetTraces.
+  //
+  // If no matching traces are found, an empty stream is returned.
+  rpc FindTraces(FindTracesRequest) returns (stream opentelemetry.proto.trace.v1.TracesData) {}
+
+  // FindTraceIDs returns a stream that retrieves IDs of traces matching query parameters.
+  //
+  // If no matching traces are found, an empty stream is returned.
+  //
+  // This call behaves identically to FindTraces, except that it returns only the list
+  // of matching trace IDs. This is useful in some contexts, such as batch jobs, where a
+  // large list of trace IDs may be queried first and then the full traces are loaded
+  // in batches.
+  rpc FindTraceIDs(FindTracesRequest) returns (FindTraceIDsResponse) {}
 }