eawsy/bavardage

// Middleware ...
func Middleware(handler func(event *Event, ctx *runtime.Context) (interface{}, error)) func(event *Event, ctx *runtime.Context) (interface{}, error) {

    // deferred
    return func(event *Event, ctx *runtime.Context) (interface{}, error) {

        setTelemetryClient(event, ctx)

        defer func() {
            r := recover()
            if r != nil { // in case of crash
                switch t := r.(type) {
                case string:
                    err := errors.New(t)
                    log.Println("is string")
                    log.Println(err)
                case error:
                    // debug.PrintStack()
                    err := t
                    log.Println("is error")
                    log.Println(err)
                    log.Println(string(debug.Stack()))
                default:
                    err := errors.New("unknown error")
                    log.Println(err)
                }
            } else { // run everytime before to terminate the process
                logger.LogJSON(event, "deferred event")
                event.Telemetry.TrackRequest(event.Env["AWS_LAMBDA_FUNCTION_NAME"], event.HTTPMethod, event.Path, event.RequestContext.RequestID, event.RequestStart, event.Duration(), event.Response.Code, event.IsSuccess())
                event.Telemetry.Channel().Flush()
            }
        }()

        return handler(event, ctx)
    }
}