Changes in proto for Player Tracking design update

This includes changes to make PlayerID consistent in casing.

Code generation will come in the next PR to make things easier to
review.

Work on #1033

proto/sdk/alpha/alpha.proto

@@ -21,44 +21,76 @@ import "google/api/annotations.proto";
 
 // SDK service to be used in the GameServer SDK to the Pod Sidecar.
 service SDK {
-    // Call when a player has connected.
-    rpc PlayerConnect (PlayerId) returns (Empty) {
+    // PlayerConnect increases the SDK’s stored player count by one, and appends this playerID to status.players.id.
+    // status.players.count and status.players.ids is then set to update to the player count and id list a second from now, unless there is already an update pending, in which case the update joins that batch operation.
+    //
+    // PlayerConnect returns true and adds the playerID to the list of playerIDs if the playerIDs was not already in the
+    // list of connected playerIDs.
+    //
+    // If the player exists within the list of connected playerIDs, PlayerConnect will return false, and the list of
+    // connected playerIDs will be left unchanged.
+    //
+    // An error will be returned if the playerID was not already in the list of connected playerIDs but the player capacity for
+    // the server has been reached. The playerID will not be added to the list of playerIDs.
+    rpc PlayerConnect (PlayerID) returns (Bool) {
         option (google.api.http) = {
             post: "/alpha/player/connect"
             body: "*"
         };
     }
 
-    // Call when a player has disconnected.
-    rpc PlayerDisconnect (PlayerId) returns (Empty) {
+    // Decreases the SDK’s stored player count by one, and removes the playerID from status.players.id
+    //
+    // status.players.count and status.players.ids is then set to update to the player count and id list a second from now, unless there is already an update pending, in which case the update joins that batch operation.
+    //
+    // PlayerDisconnect will return true and remove the supplied playerID from the list of connected playerIDs if the
+    // playerID value exists within the list.
+    //
+    // If the playerID was not in the list of connected playerIDs, the call will return false, and the connected playerID list
+    // will be left unchanged.
+    rpc PlayerDisconnect (PlayerID) returns (Bool) {
         option (google.api.http) = {
             post: "/alpha/player/disconnect"
             body: "*"
         };
     }
 
-    // Change the player capacity to a new value.
+    // Update the status.capacity value with a new capacity.
     rpc SetPlayerCapacity (Count) returns (Empty) {
         option (google.api.http) = {
             post: "/alpha/player/capacity"
             body: "*"
         };
     }
 
-    // Get the last player capacity that was set through the SDK.
+    // Retrieves the current capacity. This is always accurate, even if the value hasn’t been updated to the GameServer status yet.
     // If the player capacity is set from outside the SDK, use SDK.GameServer() instead.
-    rpc GetPlayerCapacity(Empty) returns (Count) {
+    rpc GetPlayerCapacity (Empty) returns (Count) {
         option (google.api.http) = {
             get: "/alpha/player/capacity"
         };
     }
 
-    // get the current player count
-    rpc GetPlayerCount(Empty) returns (Count) {
+    // Retrieves the current player count. This is always accurate, even if the value hasn’t been updated to the GameServer status yet.
+    rpc GetPlayerCount (Empty) returns (Count) {
         option (google.api.http) = {
             get: "/alpha/player/count"
         };
     }
+
+    // Returns if the playerID is currently connected to the GameServer. This is always accurate, even if the value hasn’t been updated to the GameServer status yet.
+    rpc IsPlayerConnected (PlayerID) returns (Bool) {
+        option (google.api.http) = {
+            get: "/alpha/player/connected/{playerID}"
+        };
+    }
+
+    // Returns the list of the currently connected player ids. This is always accurate, even if the value hasn’t been updated to the GameServer status yet.
+    rpc GetConnectedPlayers(Empty) returns (PlayerIDList) {
+        option (google.api.http) = {
+            get: "/alpha/player/connected"
+        };
+    }
 }
 
 // I am Empty
@@ -70,7 +102,17 @@ message Count {
     int64 count = 1;
 }
 
+// Store a boolean result
+message Bool {
+    bool bool = 1;
+}
+
 // The unique identifier for a given player.
-message PlayerId {
-    string playerId = 1;
+message PlayerID {
+    string playerID = 1;
+}
+
+// List of Player IDs
+message PlayerIDList {
+    repeated string list = 1;
 }

proto/sdk/sdk.proto

@@ -148,6 +148,7 @@ message GameServer {
         message PlayerStatus {
             int64 count = 1;
             int64 capacity = 2;
+            repeated string IDs = 3;
         }
 
         string state = 1;