TUN-7373: Streaming logs override for same actor

To help accommodate web browser interactions with websockets, when a
streaming logs session is requested for the same actor while already
serving a session for that user in a separate request, the original
request will be closed and the new request start streaming logs
instead. This should help with rogue sessions holding on for too long
with no client on the other side (before idle timeout or connection
close).

management/service_test.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/rs/zerolog"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"nhooyr.io/websocket"
 
@@ -59,3 +60,67 @@ func TestReadEventsLoop_ContextCancelled(t *testing.T) {
 	m.readEvents(server, ctx, events)
 	server.Close(websocket.StatusInternalError, "")
 }
+
+func TestCanStartStream_NoSessions(t *testing.T) {
+	m := ManagementService{
+		log: &noopLogger,
+		logger: &Logger{
+			Log: &noopLogger,
+		},
+	}
+	_, cancel := context.WithCancel(context.Background())
+	session := newSession(0, actor{}, cancel)
+	assert.True(t, m.canStartStream(session))
+}
+
+func TestCanStartStream_ExistingSessionDifferentActor(t *testing.T) {
+	m := ManagementService{
+		log: &noopLogger,
+		logger: &Logger{
+			Log: &noopLogger,
+		},
+	}
+	_, cancel := context.WithCancel(context.Background())
+	session1 := newSession(0, actor{ID: "test"}, cancel)
+	assert.True(t, m.canStartStream(session1))
+	m.logger.Listen(session1)
+	assert.True(t, session1.Active())
+
+	// Try another session
+	session2 := newSession(0, actor{ID: "test2"}, cancel)
+	assert.Equal(t, 1, m.logger.ActiveSessions())
+	assert.False(t, m.canStartStream(session2))
+
+	// Close session1
+	m.logger.Remove(session1)
+	assert.True(t, session1.Active()) // Remove doesn't stop a session
+	session1.Stop()
+	assert.False(t, session1.Active())
+	assert.Equal(t, 0, m.logger.ActiveSessions())
+
+	// Try session2 again
+	assert.True(t, m.canStartStream(session2))
+}
+
+func TestCanStartStream_ExistingSessionSameActor(t *testing.T) {
+	m := ManagementService{
+		log: &noopLogger,
+		logger: &Logger{
+			Log: &noopLogger,
+		},
+	}
+	actor := actor{ID: "test"}
+	_, cancel := context.WithCancel(context.Background())
+	session1 := newSession(0, actor, cancel)
+	assert.True(t, m.canStartStream(session1))
+	m.logger.Listen(session1)
+	assert.True(t, session1.Active())
+
+	// Try another session
+	session2 := newSession(0, actor, cancel)
+	assert.Equal(t, 1, m.logger.ActiveSessions())
+	assert.True(t, m.canStartStream(session2))
+	// session1 is removed and stopped
+	assert.Equal(t, 0, m.logger.ActiveSessions())
+	assert.False(t, session1.Active())
+}