 		//only care if it is one of our containers
 		guard let from = try? event.json.getString(at:"from"),
 			let ctype = ContainerType.from(imageName:from),
-			let container = containers[ctype] else { return }
+			let container = self.containers[ctype] else { return }
 		switch event.eventType {
 			case .die:
 				os_log("warning: container died: %{public}@", log:.docker, from)

	/// - returns: a signal producer with no value
	public func perform(operation: DockerContainerOperation, on inContainers: [DockerContainer]? = nil) -> SignalProducer<(), Rc2Error>
	{
		var selectedContainers = containers!
		if inContainers != nil {
			selectedContainers = inContainers!
		}

///manages communicating with the local docker engine
public final class DockerManager: NSObject {
	// MARK: - Properties
	/// the containers managed.
	// these should always be referred to as self.containers since many parameters have the name containers
	public fileprivate(set) var containers: [DockerContainer]!
	public var isReady: Bool { return state == .ready }

