Listener Cannot Close Session - Missing Close Method Call

[coolguy1771]

The Listener.Run method currently leaks message sessions. Because the Client interface lacks a Close method, the listener exits—whether via context cancellation or error—without notifying the server. This results in "zombie" sessions and resource leaks on the scaleset API.

Proposed Changes

Update Client interface: Add Close(ctx context.Context) error to allow for graceful session termination.
Implement cleanup in Run: Use a defer block to ensure Close is called on exit.

Note: The cleanup uses context.Background() with a timeout because the primary ctx is likely already cancelled when the defer triggers.

type Client interface {
    GetMessage(ctx context.Context, lastMessageID, maxCapacity int) (*scaleset.RunnerScaleSetMessage, error)
    DeleteMessage(ctx context.Context, messageID int) error
    Session() scaleset.RunnerScaleSetSession
    Close(ctx context.Context) error // Added
}

func (l *Listener) Run(ctx context.Context, scaler Scaler) error {
    defer func() {
        // Ensure session cleanup even if parent context is cancelled
        cleanupCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
        defer cancel()
        
        if err := l.client.Close(cleanupCtx); err != nil {
            l.logger.Error("failed to close session", "error", err)
        }
    }()
    
    for {
        select {
        case <-ctx.Done():
            return ctx.Err()
        default:
            // ... processing logic ...
        }
    }
}