Sesame-Server/Sources/App/configure.swift

import Vapor

var keyManager: KeyManagement!

// configures your application
public func configure(_ app: Application) throws {
    app.http.server.configuration.port = 6003
    
    let storageFolder = URL(fileURLWithPath: app.directory.resourcesDirectory)
    let keyFile = storageFolder.appendingPathComponent("device.key")
    let deviceKey = try String(contentsOf: keyFile)
        .trimmingCharacters(in: .whitespacesAndNewlines)
    keyManager = KeyManagement(deviceKey: deviceKey)
    try routes(app)
    
    // Gracefully shut down by closing potentially open socket
    DispatchQueue.global(qos: .utility).asyncAfter(deadline: .now() + .seconds(5)) {
        _ = app.server.onShutdown.always { _ in
            keyManager.removeDeviceConnection()
        }
    }
}