Restrict multiple devices per Nakama account #169

Germ-99 · 2025-11-26T23:12:23Z

Fixes: #168

Copilot

Pull request overview

This PR implements restrictions on multiple device connections per Nakama account to prevent users from simultaneously joining matches as players from different devices while allowing spectator access.

Key Changes:

Added CountSessionsForUser() method to track active sessions per user
Implemented restrictions for secondary connections: spectator-only access for matches, no session creation, and no social lobby access
Added new error code SecondaryConnectionRestricted for handling violations

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
server/session_registry.go	Added `CountSessionsForUser()` interface method and implementation to count active sessions per user
server/match_common_test.go	Added mock implementation of `CountSessionsForUser()` for test registry
server/evr_lobby_session.go	Added multi-session checks to restrict secondary connections to spectator role and prevent session creation
server/evr_lobby_join.go	Added check to prevent secondary connections from accessing social lobbies
server/evr_lobby_find.go	Added check to prevent secondary connections from finding social lobbies
server/evr_lobby_errors.go	Added new error code `SecondaryConnectionRestricted` for multi-session violations

Copilot · 2025-11-27T00:20:11Z

server/evr_lobby_session.go

+	// Check if this is a secondary connection and restrict it 
+	sessionCount := p.sessionRegistry.CountSessionsForUser(session.UserID())
+	if sessionCount > 1 {
+		// This user has multiple sessions open
+		switch in.(type) {
+		case *evr.LobbyFindSessionRequest:
+			// For find requests, only allow spectator role
+			if lobbyParams.Role != evr.TeamSpectator {
+				logger.Warn("Secondary connection attempted to join as player",
+					zap.String("user_id", session.UserID().String()),
+					zap.String("session_id", session.ID().String()),
+					zap.String("role", TeamIndex(lobbyParams.Role).String()))
+				return NewLobbyError(SecondaryConnectionRestricted, "secondary connections can only spectate")
+			}
+
+		case *evr.LobbyJoinSessionRequest:
+			// Join requests also need spectator check if non-spectator role requested
+			if lobbyParams.Role != evr.TeamSpectator {
+				logger.Warn("Secondary connection attempted to join as player",
+					zap.String("user_id", session.UserID().String()),
+					zap.String("session_id", session.ID().String()),
+					zap.String("role", TeamIndex(lobbyParams.Role).String()))
+				return NewLobbyError(SecondaryConnectionRestricted, "secondary connections can only spectate")
+			}
+
+		case *evr.LobbyCreateSessionRequest:
+			// Secondary connections cannot create sessions
+			logger.Warn("Secondary connection attempted to create session",
+				zap.String("user_id", session.UserID().String()),
+				zap.String("session_id", session.ID().String()))
+			return NewLobbyError(SecondaryConnectionRestricted, "secondary connections cannot create sessions")
+		}
+	}


The new multi-session restriction logic introduced in this function lacks test coverage. Consider adding unit tests to verify:

Secondary connections (sessionCount > 1) are restricted to spectator role for LobbyFindSessionRequest

Secondary connections are restricted to spectator role for LobbyJoinSessionRequest

Secondary connections cannot create sessions (LobbyCreateSessionRequest)

Primary connections (sessionCount == 1) are not affected by these restrictions

Tests should be added to an appropriate EVR test file (e.g., evr_lobby_session_test.go).

Copilot · 2025-11-27T00:20:12Z

server/evr_lobby_join.go

+	// Check if this is a secondary connection and prevent social lobby access
+	sessionCount := p.sessionRegistry.CountSessionsForUser(session.UserID())
+	if sessionCount > 1 && (label.Mode == evr.ModeSocialPublic || label.Mode == evr.ModeSocialPrivate) {
+		logger.Warn("Secondary connection attempted to join social lobby",
+			zap.String("user_id", session.UserID().String()),
+			zap.String("session_id", session.ID().String()),
+			zap.String("mode", label.Mode.String()))
+		return NewLobbyError(SecondaryConnectionRestricted, "secondary connections cannot access social lobbies")
+	}


The social lobby restriction for secondary connections lacks test coverage. Consider adding unit tests to verify:

Secondary connections are blocked from joining social lobbies (both ModeSocialPublic and ModeSocialPrivate)

Primary connections can join social lobbies normally

The correct error is returned when restrictions apply

Tests should be added to an appropriate EVR test file (e.g., evr_lobby_join_test.go).

Copilot · 2025-11-27T00:20:12Z

server/evr_lobby_find.go

+	// Check if this is a secondary connection and prevent social lobby access
+	sessionCount := p.sessionRegistry.CountSessionsForUser(session.UserID())
+	if sessionCount > 1 && lobbyParams.Mode == evr.ModeSocialPublic {
+		logger.Warn("Secondary connection attempted to access social lobby",
+			zap.String("user_id", session.UserID().String()),
+			zap.String("session_id", session.ID().String()))
+		return NewLobbyError(SecondaryConnectionRestricted, "secondary connections cannot access social lobbies")
+	}


The social lobby restriction for secondary connections lacks test coverage. Consider adding unit tests to verify:

Secondary connections are blocked from finding social lobbies

Primary connections can find social lobbies normally

The correct error is returned when restrictions apply

Tests should be added to an appropriate EVR test file (e.g., evr_lobby_find_test.go).

Copilot · 2025-11-27T00:20:12Z

server/evr_lobby_find.go


+	// Check if this is a secondary connection and prevent social lobby access
+	sessionCount := p.sessionRegistry.CountSessionsForUser(session.UserID())
+	if sessionCount > 1 && lobbyParams.Mode == evr.ModeSocialPublic {


Inconsistent restriction logic: In evr_lobby_join.go (line 38), the check includes both ModeSocialPublic and ModeSocialPrivate, but here only ModeSocialPublic is checked. Secondary connections should be restricted from ModeSocialPrivate lobbies as well for consistency.

Consider changing this to:

if sessionCount > 1 && (lobbyParams.Mode == evr.ModeSocialPublic || lobbyParams.Mode == evr.ModeSocialPrivate) {

Suggested change

if sessionCount > 1 && lobbyParams.Mode == evr.ModeSocialPublic {

if sessionCount > 1 && (lobbyParams.Mode == evr.ModeSocialPublic || lobbyParams.Mode == evr.ModeSocialPrivate) {

Copilot · 2025-11-27T00:20:13Z

server/evr_lobby_session.go

 	var err error
 	var matchID MatchID

+	// Check if this is a secondary connection and restrict it 


Trailing whitespace at end of line

Suggested change

// Check if this is a secondary connection and restrict it

// Check if this is a secondary connection and restrict it

Copilot · 2025-11-27T00:20:13Z

server/session_registry.go

+func (r *LocalSessionRegistry) CountSessionsForUser(userID uuid.UUID) int {
+	count := 0
+	r.sessions.Range(func(id uuid.UUID, session Session) bool {
+		if session.UserID() == userID {
+			count++
+		}
+		return true
+	})
+	return count
+}


The CountSessionsForUser function iterates through all active sessions on every call. This could become a performance bottleneck with many concurrent sessions, especially since this method is called for every lobby request.

Consider:

Maintaining a separate index map from userID to session count that's updated in Add() and Remove() methods for O(1) lookups

Or caching the result with appropriate invalidation when sessions are added/removed

thesprockee

@copilot implement changes based on the review. use the stream count for the user.

use something akin to nk.StreamCount(StreamModeService, <user_id>, "", StreamLabelMatchService) to see if the user has any other match connections active.

thesprockee · 2025-11-27T00:19:11Z

server/evr_lobby_errors.go

 	SuspendedFromLobbyGroup
 	KickedFromLobbyGroup
 	NotALobbyGroupMod
+	SecondaryConnectionRestricted


Do not add to the LobbyErrorCodeValue's, as they are hard coded in the EVR client.

thesprockee · 2025-11-27T00:20:13Z

server/evr_lobby_errors.go

 	SuspendedFromLobbyGroup: "suspended_from_lobby_group",
 	KickedFromLobbyGroup:    "kicked_from_lobby_group",
 	NotALobbyGroupMod:       "not_a_lobby_group_mod",
+	SecondaryConnectionRestricted: "secondary_connection_restricted",


Do not add to the LobbyErrorCodeValue's, as they are hard coded in the EVR client.

thesprockee · 2025-11-27T00:20:55Z

server/session_registry.go

this is an "upstream" file, do not modify it.

thesprockee · 2025-11-27T00:21:13Z

server/match_common_test.go

this is an "upstream" file, do not modify it.

thesprockee · 2025-11-27T00:21:54Z

server/evr_lobby_session.go

+				return NewLobbyError(SecondaryConnectionRestricted, "secondary connections can only spectate")
+			}
+
+		case *evr.LobbyCreateSessionRequest:


allow secondary connections to create sessions, as long as they are spectators.

thesprockee · 2025-11-27T00:23:02Z

server/evr_lobby_find.go


 	startTime := time.Now()

+	// Check if this is a secondary connection and prevent social lobby access


this is duplicated in server/evr_lobby_session.go

thesprockee · 2025-11-27T00:23:15Z

server/evr_lobby_join.go

 	lobbyParams.GroupID = label.GetGroupID()
 	lobbyParams.Mode = label.Mode

+	// Check if this is a secondary connection and prevent social lobby access


this is duplicated from server/evr_lobby_session.go

Restrict multiple devices per Nakama account

99ad14b

thesprockee requested a review from Copilot November 27, 2025 00:15

Copilot started reviewing on behalf of thesprockee November 27, 2025 00:15 View session

Copilot finished reviewing on behalf of thesprockee November 27, 2025 00:17

Copilot AI reviewed Nov 27, 2025

View reviewed changes

thesprockee requested changes Nov 27, 2025

View reviewed changes

thesprockee force-pushed the main branch from 0a2b882 to 33f8eab Compare December 16, 2025 14:05

	if sessionCount > 1 && lobbyParams.Mode == evr.ModeSocialPublic {
	if sessionCount > 1 && (lobbyParams.Mode == evr.ModeSocialPublic \|\| lobbyParams.Mode == evr.ModeSocialPrivate) {

	// Check if this is a secondary connection and restrict it
	// Check if this is a secondary connection and restrict it


		startTime := time.Now()

		// Check if this is a secondary connection and prevent social lobby access

Restrict multiple devices per Nakama account #169

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Germ-99 commented Nov 26, 2025

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