[identity] Add RPC for finding user ID

Summary:
[[ https://linear.app/comm/issue/ENG-4132/identity-service-rpc-to-check-if-a-username-exists | ENG-4132 ]]. Added RPC to find user ID by either username or wallet address.
The API is the same as for GetOutboundKeys RPC, which will then be refactored to instead accept user ID.

Test Plan: Created a test user, used BloomRPC to call the RPC with the username. It returned the user ID - confirmed with DDB. A unit test is added in the next diff.

Reviewers: varun, ashoat, michal, wyilio

Reviewed By: varun

Subscribers: tomek, wyilio

Differential Revision: https://phab.comm.dev/D9834

services/identity/src/grpc_services/authenticated.rs

@@ -1,6 +1,6 @@
 use crate::{
   client_service::handle_db_error, constants::request_metadata,
-  database::DatabaseClient, grpc_services::shared::get_value,
+  database::DatabaseClient, grpc_services::shared::get_value, token::AuthType,
 };
 use tonic::{Request, Response, Status};
 
@@ -14,7 +14,8 @@ pub mod auth_proto {
   tonic::include_proto!("identity.authenticated");
 }
 use auth_proto::{
-  identity_client_service_server::IdentityClientService, KeyserverKeysResponse,
+  find_user_id_request, identity_client_service_server::IdentityClientService,
+  FindUserIdRequest, FindUserIdResponse, KeyserverKeysResponse,
   OutboundKeyInfo, OutboundKeysForUserRequest, RefreshUserPreKeysRequest,
   UploadOneTimeKeysRequest,
 };
@@ -169,4 +170,28 @@ impl IdentityClientService for AuthenticatedService {
 
     Ok(tonic::Response::new(Empty {}))
   }
+
+  async fn find_user_id(
+    &self,
+    request: tonic::Request<FindUserIdRequest>,
+  ) -> Result<tonic::Response<FindUserIdResponse>, tonic::Status> {
+    let message = request.into_inner();
+
+    use find_user_id_request::Identifier;
+    let (user_ident, auth_type) = match message.identifier {
+      None => {
+        return Err(tonic::Status::invalid_argument("no identifier provided"))
+      }
+      Some(Identifier::Username(username)) => (username, AuthType::Password),
+      Some(Identifier::WalletAddress(address)) => (address, AuthType::Wallet),
+    };
+
+    let user_id = self
+      .db_client
+      .get_user_id_from_user_info(user_ident, &auth_type)
+      .await
+      .map_err(handle_db_error)?;
+
+    Ok(Response::new(FindUserIdResponse { user_id }))
+  }
 }

shared/protos/identity_authenticated.proto

@@ -23,6 +23,9 @@ service IdentityClientService {
   // to a user's keyserver
   rpc GetKeyserverKeys(OutboundKeysForUserRequest) returns
     (KeyserverKeysResponse) {}
+
+  // Returns userID for given username or wallet address
+  rpc FindUserID(FindUserIDRequest) returns (FindUserIDResponse) {}
 }
 
 // Helper types
@@ -62,3 +65,17 @@ message KeyserverKeysResponse {
 message OutboundKeysForUserRequest {
   string userID = 1;
 }
+
+// FindUserID
+
+message FindUserIDRequest {
+  oneof identifier {
+    string username = 1;
+    string walletAddress = 2;
+  }
+}
+
+message FindUserIDResponse {
+  // none if user not found
+  optional string userID = 1;
+}