func init() {
myservices["lookup"] = getServiceDesc
myservices["register"] = registerService
myservices[msg.PPP_HEARTBEAT] = msg.ProcessHeartBeat
services["lookup"] = msg.NewService("lookup", "LooKUp Service", "tcp://localhost:5569", "lookup", "REP")
services["register"] = msg.NewService("register", "Registration Service", "tcp://localhost:5569", "lookup", "REP")
// Load Service List
getServiceList()
// List available services
listServices()
}
// Initialize by setting address and registering service with directory service
func init() {
myservices["hello"] = doHelloWorld
myservices[msg.PPP_HEARTBEAT] = msg.ProcessHeartBeat
allowedbinders = "tcp://*:5560"
mydescription = msg.NewService("hello", "Hello Service", "tcp://localhost:5560", "hello", "REP")
// All I need to know are the details of the lookup service
services["lookup"] = msg.NewService("lookup", "LookUp Service", "tcp://localhost:5569", "lookup", "REP")
fmt.Println("Registering service...")
reply, err := msg.SendRequest(services["lookup"], "register", string(encodeTOJSON(mydescription)))
if err != nil {
log.Println(err)
}
fmt.Println("\t", reply)
}
// Populates the services map with mappings for available
// services - services is a global variable hence no need
// for return
func getServiceList() {
//read service list from file
filepointer, err := os.Open(SERVICES_FILENAME)
if err != nil {
log.Println(err)
return
}
defer filepointer.Close()
reader := bufio.NewReader(filepointer)
line, err := reader.ReadBytes('\n')
service := msg.NewService("", "", "", "", "")
for err == nil {
///*Decode from JSON
err = json.Unmarshal(line, &service)
if err != nil {
log.Println("Error decoding from json")
continue
}
if _, isPresent := services[service.SID]; !isPresent {
services[service.SID] = service
}
//read next line
line, err = reader.ReadBytes('\n')
}
if err != io.EOF {
log.Println(err)
}
}
// Populates the services map with mappings for available
// services - services is a global variable hence no need
// for return
func getServiceList() {
//read service list from file
filepointer, err := os.Open(servicesFileName)
if err != nil {
log.Println(err)
return
}
defer filepointer.Close()
reader := bufio.NewReader(filepointer)
line, err := reader.ReadBytes('\n')
service := msg.NewService("", "", "", "", "")
for err == nil {
// Decode from JSON
err = json.Unmarshal(line, &service)
if err != nil {
log.Println("Error decoding from json")
continue
}
fmt.Println(service.SID)
services[service.SID] = service
//read next line
line, err = reader.ReadBytes('\n')
}
if err != io.EOF {
log.Println(err)
}
}
// Registers a new service by:
// 1. Decoding the JSON "register" message
// 2. Adding the decoded service to the service list
// 3. Encoding Entire service list to JSON and saving to file
func registerService(message string) (reply string, err error) {
newservice := msg.NewService("", "", "", "", "")
if len(services) == 0 {
services = make(map[string]msg.Service)
}
fmt.Println("\n\tProcessing Service Registration Request for ", message, " ...")
//Decode Message
fmt.Println("\tDecoding...")
err = json.Unmarshal([]byte(message), &newservice)
if err != nil {
log.Println("Error decoding from JSON ", err)
err = errors.New(fmt.Sprintf("DecodeFail:%s", err))
reply = fmt.Sprintf("%s", err)
return
}
// Append latest heartbeat to the service description
newservice.Heartbeat_state = time.Now().String()
fmt.Println("\tRegistering...")
//Add to the active service list
services[newservice.SID] = newservice
fmt.Println("\tUpdating file...")
//Encode entire service list to JSON
var datab, b []byte
for _, value := range services {
b, err = json.Marshal(value)
if err != nil {
log.Println("Error encoding ", value.SID, " to JSON")
err = errors.New(fmt.Sprintf("WriteFileFail:EncodeFail:%s", err))
reply = fmt.Sprintf("%s", err)
return
}
datab = append(datab, append(b, byte('\n'))...)
}
//write to file
err = ioutil.WriteFile(SERVICES_FILENAME, datab, os.ModePerm)
if err != nil {
log.Println("Error writing service list to file: ", err)
err = errors.New(fmt.Sprintf("WriteFileFail:%s", err))
reply = fmt.Sprintf("%s", err)
return
}
// Updated service list
listServices()
reply = "RegistrationSuccess"
return
}
// Registers a new service by:
// 1. Decoding the JSON message
// 2. Adding the decoded service and its socket binding to the service list
// 3. Encoding Entire service list to JSON and saving to file
func registerService(jsonMsg, SID string) {
if jsonMsg == "NotAvailable" {
err := "Service, " + SID + ", Not available"
panic(err)
}
newservice := msg.NewService("", "", "", "", "")
if len(services) == 0 {
services = make(map[string]msg.Service)
}
//Decode Message
fmt.Println("\tDecoding...")
err := json.Unmarshal([]byte(jsonMsg), &newservice)
if err != nil {
panic(err)
}
fmt.Println("\tRegistering...")
//Add to the active service list
services[newservice.SID] = newservice
fmt.Println("\tUpdating file...")
//Encode entire service list to JSON
var datab, b []byte
for _, value := range services {
b, err = json.Marshal(value)
if err != nil {
log.Println("Error encoding ", value.SID, " to JSON\n",
"Service has been registered in service list but will have to ",
"be reloaded on next run\n", err)
return
}
datab = append(datab, append(b, byte('\n'))...)
}
//write to file
err = ioutil.WriteFile(servicesFileName, datab, os.ModePerm)
if err != nil {
log.Println("Error writing service list to file: ", err,
"\nService has been registered in service list but will have to be",
" reloaded on next run")
return
}
}
// Init function requests for all services that the client will require
func init() {
servicesFileName = "dcservicelist.json"
servicesReq = append(servicesReq, "hello")
// All I need to know are the details of the lookup service
services["lookup"] = msg.NewService("lookup", "LookUp Service", "tcp://localhost:5569", "lookup", "REP")
// Get my service list
getServiceList()
// Get all services I require that are not listed in my service list
for _, serviceReq := range servicesReq {
if _, isListed := services[serviceReq]; isListed == false {
reply, err := msg.SendRequest(services["lookup"], "lookup", serviceReq)
if err != nil {
panic(err)
}
for i := range reply {
registerService(reply[i], serviceReq)
}
}
}
}