fix: refactor signaler; fix logic for local watcher

proto/signaler_service.proto

@@ -11,23 +11,17 @@ service SignalerService {
     // Optionally, wait_for_update can be set to prevent returning until the Camera has seen the
     // session request, populated candidates, and returned a session offer.
     rpc CreateSession(CreateSessionRequest) returns (Session);
-    // UpdateSession updates the session
-    rpc UpdateSession(UpdateSessionRequest) returns (Session);
-    // ListSessions lists all sessions the client should consider.
+    // PopSession deletes a session from the list of sessions, and returns it.
     //
-    // TODO: it would be better if we could alert a camera to poll for sessions
-    // i.e., with websockets (or streaming RPCs).
-    rpc ListSessions(ListSessionsRequest) returns (ListSessionsResponse);
+    // If there are no sessions, this blocks until one becomes available.
+    rpc PopSession(PopSessionRequest) returns (Session);
 
-    // CreateIceCandidate adds the provided candidate to the list of candidates.
-    rpc CreateIceCandidate(CreateIceCandidateRequest) returns (IceCandidate);
-    // PopIceCandidate delete a candidate from the list of candidates and returns it.
+    // CreateIceMessage adds the provided message to the list of candidates.
+    rpc CreateIceMessage(CreateIceMessageRequest) returns (IceMessage);
+    // PopIceCandidate delete a message from the list of messages and returns it.
     //
-    // If there are no candidates, this blocks until one becomes available.
-    rpc PopIceCandidate(PopIceCandidateRequest) returns (IceCandidate);
-
-    rpc CreateIceSessionDescription(CreateIceSessionDescriptionRequest) returns (IceSessionDescription);
-    rpc PopIceSessionDescription(PopIceSessionDescriptionRequest) returns (IceSessionDescription);
+    // If there are no messages, this blocks until one becomes available.
+    rpc PopIceMessage(PopIceMessageRequest) returns (IceMessage);
 
 }
 
@@ -63,6 +57,10 @@ message CreateSessionRequest {
     bool wait_for_update = 2;
 }
 
+message PopSessionRequest {
+    Session session = 1;
+}
+
 message UpdateSessionRequest {
     Session session = 1;
 
@@ -78,21 +76,12 @@ message ListSessionsResponse {
     repeated Session sessions = 1;
 }
 
-message CreateIceCandidateRequest {
+message CreateIceMessageRequest {
     Session.Identifier session_identifier = 1;
-    IceCandidate candidate = 2;
+    IceMessage ice_message = 2;
 }
 
-message PopIceCandidateRequest {
-    Session.Identifier session_identifier = 1;
-}
-
-message CreateIceSessionDescriptionRequest {
-    Session.Identifier session_identifier = 1;
-    IceSessionDescription description = 2;
-}
-
-message PopIceSessionDescriptionRequest {
+message PopIceMessageRequest {
     Session.Identifier session_identifier = 1;
 }
 
@@ -103,6 +92,13 @@ message Camera {
     Identifier identifier = 1;
 }
 
+message IceMessage {
+    oneof type {
+        IceCandidate candidate = 1;
+        IceSessionDescription session = 2;
+    }
+}
+
 message IceCandidate {
     // Copied from https://pkg.go.dev/github.com/pion/webrtc/v4#ICECandidateInit
     string candidate = 1;
@@ -123,11 +119,6 @@ message Session {
     }
     Identifier id = 1;
     Camera.Identifier camera = 2;
-    repeated IceCandidate client_ice_candidates = 3;
-    repeated IceCandidate camera_ice_candidates = 4;
-
-    IceSessionDescription camera_offer = 5;
-    IceSessionDescription client_answer = 6;
 }
 
 message AuthToken {