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: cannot use UpperCaseHandler (typefunc(asl.MessageDelivery)) as type asl.MessageHandler in assignment ./chains.go:37:86: cannot use RepeatHandler (type func(asl.MessageDelivery)) as type asl.MessageHandler in argument to Repeater.ConsumeFunc
type MessageDelivery struct {
Delivery amqp.Delivery
Message interface{}
Error error
Context *Context
}
type MessageGenerator func() interface{}
type MessageHandler func(MessageDelivery) (interface{}, error)
I tried running the code,where am i going wrong,how do i right pass function as argument to another function. The function returns interface and error. Though function is taking MessageDelivery Struct as argument,function signature is same.where am i going wrong
You are passing the function as an argument correctly but they do not match the expected signature. Change your functions to:
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
}