package main import ( "log" "strings" "asl.com/asl" ) /* Trivial service to demonstrate chaining service together Message starts in originator, travels through a couple formatters, and then gets back to originator */ type MessageTest struct { Body string `json:"body"` } var s *asl.Service func main() { var ( err error cid string ) //var m MessageDelivery var g asl.MessageHandler g = UpperCaseHandler // UpperCaser := asl.NewService("UpperCaser", "", false) UpperCaser := asl.NewService("UpperCaser") if err = UpperCaser.ConsumeFunc("asl-service-uc", []string{"asl-service-uc"},func() interface{} { return "" },g); err != nil { log.Fatalf("Error starting consumer: %v", err) } // Repeater := asl.NewService("Repeater", "", false) Repeater := asl.NewService("Repeater") if err = Repeater.ConsumeFunc("asl-service-repeat", []string{"asl-service-repeat"}, func() interface{} { return "" }, RepeatHandler); err != nil { //if err = Repeater.ConsumeFunc("asl-service-repeat", []string{"asl-service-repeat"}, mg asl.MessageGenerator, mh asl.MessageHandler); err != nil { log.Fatalf("Error starting consumer: %v", err) } // originator := asl.NewService("Originator", "", false) originator := asl.NewService("Originator") deliveryChan := make(chan asl.MessageDelivery) m := asl.MessagePublishing{ Message: MessageTest{"this is a test"}, RoutingKeys: []string{"asl-service-uc", "asl-service-repeat"}, } if cid, err = originator.RPCPublish(m, deliveryChan); err != nil { log.Fatalf("Failed to publish: %v", err) } message := <-deliveryChan log.Printf("Originator Got: %+v", message.Message) originator.RemoveQueue(cid) UpperCaser.Wait() } func UpperCaseHandler(md asl.MessageDelivery) { s.Reply(MessageTest{strings.ToUpper(md.Message.(string))}, md.Delivery) } func RepeatHandler(md asl.MessageDelivery) { s.Reply(MessageTest{strings.Repeat(md.Message.(string), 5)}, md.Delivery) } package asl
Error ./chains.go:26:10:不能在作业中使用UpperCaseHandler(typefunc(asl.MessageDelivery))作为asl.MessageHandler类型./chains.go:37:86:无法使用RepeatHandler(类型func(asl.MessageDelivery))与Repeater.ConsumeFunc的参数中的asl.MessageHandler类型相同
Error
./chains.go:26:10:不能在作业中使用UpperCaseHandler(typefunc(asl.MessageDelivery))作为asl.MessageHandler类型./chains.go:37:86:无法使用RepeatHandler(类型func(asl.MessageDelivery))与Repeater.ConsumeFunc的参数中的asl.MessageHandler类型相同
type MessageDelivery struct { Delivery amqp.Delivery Message interface{} Error error Context *Context } type MessageGenerator func() interface{} type MessageHandler func(MessageDelivery) (interface{}, error)
我试图运行代码,哪里出了问题,我该如何正确地将函数作为参数传递给另一个函数。该函数返回接口和错误。虽然函数以MessageDelivery Struct作为参数,但是函数签名是相同的。
您正确地将该函数作为参数传递,但是它们与预期的签名不匹配。将功能更改为:
func UpperCaseHandler(md busboy.MessageDelivery) (interface{}, error} { s.Reply(MessageTest{strings.ToUpper(md.Message.(string))}, md.Delivery) return nil, nil } func RepeatHandler(md busboy.MessageDelivery) (interface{}, error} { s.Reply(MessageTest{strings.Repeat(md.Message.(string), 5)}, md.Delivery) return nil, nil }