[remote-storage][v2] Add proto definition for GetTraces rpc (#6730)

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

## Description of the changes
- This PR creates a protobuf definition in `traces_storage.proto` that
will contain the API for all methods pertaining to the traces storage.

## 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

@@ -0,0 +1,49 @@
+syntax = "proto3";
+
+package jaeger.storage.v2;
+
+import "gogoproto/gogo.proto";
+import "google/protobuf/timestamp.proto";
+import "opentelemetry/proto/trace/v1/trace.proto";
+
+option go_package = "storage";
+
+// GetTraceParams represents the query for a single trace from the storage backend.
+message GetTraceParams {
+    // trace_id is a 16 byte array containing the unique identifier for the trace to query. 
+    bytes trace_id = 1;
+
+    // start_time is the start of the time interval to search for the trace_id.
+    //
+    // This field is optional.
+    google.protobuf.Timestamp start_time = 2 [
+      (gogoproto.stdtime) = true
+    ];
+
+    // end_time is the end of the time interval to search for the trace_id.
+    //
+    // This field is optional.
+    google.protobuf.Timestamp end_time = 3 [
+      (gogoproto.stdtime) = true
+    ];
+}
+
+// GetTracesRequest represents a request to retrieve multiple traces.
+message GetTracesRequest {
+  repeated GetTraceParams query = 1;
+}
+
+service TraceReader {
+	// GetTraces returns a stream that retrieves all traces with given IDs.
+	//
+	// Chunking requirements:
+	// - A single TracesData chunk MUST NOT contain spans from multiple traces.
+	// - Large traces MAY be split across multiple, *consecutive* TracesData chunks.
+	// - Each returned TracesData object MUST NOT be empty.
+	//
+	// 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) {}
+}

scripts/makefiles/Protobuf.mk

@@ -24,7 +24,8 @@ PATCHED_OTEL_PROTO_DIR = proto-gen/.patched-otel-proto
 PROTO_INCLUDES := \
 	-Iidl/proto/api_v2 \
 	-Imodel/proto/metrics \
-	-I/usr/include/github.com/gogo/protobuf
+	-I/usr/include/github.com/gogo/protobuf \
+	-Iidl/opentelemetry-proto
 
 # Remapping of std types to gogo types (must not contain spaces)
 PROTO_GOGO_MAPPINGS := $(shell echo \
@@ -79,6 +80,7 @@ endef
 
 .PHONY: proto
 proto: proto-storage-v1 \
+	proto-storage-v2 \
 	proto-hotrod \
 	proto-zipkin \
 	proto-openmetrics \
@@ -107,6 +109,10 @@ proto-storage-v1:
 		--go_out=$(PWD)/internal/storage/v1/grpc/proto/ \
 		internal/storage/v1/grpc/proto/storage_test.proto
 
+.PHONY: proto-storage-v2
+proto-storage-v2:
+	$(call proto_compile, proto-gen/storage/v2, internal/storage/v2/grpc/trace_storage.proto, -Iinternal/storage/v2/grpc/)
+
 .PHONY: proto-hotrod
 proto-hotrod:
 	$(call proto_compile, , examples/hotrod/services/driver/driver.proto)