VS Code error when running go application - go

Question

I am new to go and I am following a tutorial online. I get this error from VS Code
"cannot use c.ReadConfig (type func(http.ResponseWriter, *http.Request)) as type http.Handler in argument to router.Get:
func(http.ResponseWriter, *http.Request) does not implement http.Handler (missing ServeHTTP method)".
I checked the Get and Redconfig functions and they look alright. The teacher on his end does not get the error and he is able to run the Go code fine. this is the snippet in the main
This the main function
func main() {
config := domain.Config{}
configService := service.ConfigService{
Config: &config,
Location: "config.yaml",
}
go configService.Watch(time.Second * 30)
c := controller.Controller{
Config: &config,
}
router := muxinator.NewRouter()
router.Get("/read/{serviceName}", c.ReadConfig)
log.Fatal(router.ListenAndServe(":8080"))
}
This is the Get function
// Get returns the config for a particular service
func (c *Config) Get(serviceName string) (map[string]interface{}, error) {
c.lock.RLock()
defer c.lock.RUnlock()
a, ok := c.config["base"].(map[string]interface{})
if !ok {
return nil, fmt.Errorf("base config is not a map")
}
// If no config is defined for the service
if _, ok = c.config[serviceName]; !ok {
// Return the base config
return a, nil
}
b, ok := c.config[serviceName].(map[string]interface{})
if !ok {
return nil, fmt.Errorf("service %q config is not a map", serviceName)
}
// Merge the maps with the service config taking precedence
config := make(map[string]interface{})
for k, v := range a {
config[k] = v
}
for k, v := range b {
config[k] = v
}
return config, nil
}
This is ReadConfig
// ReadConfig writes the config for the given service to the ResponseWriter
func (c *Controller) ReadConfig(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json; charset=UTF-8")
vars := mux.Vars(r)
serviceName, ok := vars["serviceName"]
if !ok {
w.WriteHeader(http.StatusBadRequest)
fmt.Fprintf(w, "error")
}
config, err := c.Config.Get(serviceName)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
fmt.Fprintf(w, "error")
}
rsp, err := json.Marshal(&config)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
fmt.Fprintf(w, "error")
}
w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, string(rsp))
}
What should happen is that I should be able to run and I can go to http://localhost:8080/read/base

Answer 1

Use http.HandlerFunc:
router := muxinator.NewRouter()
router.Get("/read/{serviceName}", http.HandlerFunc(c.ReadConfig))
It's expecting a ServeHTTP method, but you gave it a direct function. http.HandlerFunc acts as a wrapper so you can use a plain function as your handler.