Using a global variable in golang

Question

I have a global variable that I am trying to use across two different functions, and unable to figure out why the following code is not working... ``` package main import ( "github.com/ant0ine/go-json-rest/rest" "log" "net" "net/http" ) type Message struct { Body string } var api rest.Api func hostLookup(w rest.ResponseWriter, req *rest.Request) { ip, err := net.LookupIP(req.PathParam("host")) if err != nil { rest.Error(w, err.Error(), http.StatusInternalServerError) return } w.WriteJson(&ip) } func foo() { api := rest.NewApi() api.Use(rest.DefaultDevStack...) router, err := rest.MakeRouter( &rest.Route{"GET", "/lookup/#host", hostLookup}, ) if err != nil { log.Fatal(err) } api.SetApp(router) } func bar() { log.Fatal(http.ListenAndServe(":8080", api.MakeHandler())) } func main() { foo() bar() } ``` The above code does not work... the HTTP server does not route the request to the hostLookup function. However - if I move the following line from bar() ``` log.Fatal(http.ListenAndServe(":…

Accepted Answer

Your problem is two fold...

For one, you declare

```
var api rest.Api
```

but the rest.New() returns a *rest.Api

```
func NewApi() *Api {
```

Secondly, in your `foo()` function, you are creating a local variable called `api` instead of using your package variable.

Instead of

```
api := rest.NewApi()
```

It should be

```
api = rest.NewApi()
```

So, the fix is to add a `*` before `rest.Api` as in `var api *rest.Api` and remove a colon from the setting of api as in `api = rest.NewApi()`

Using a global variable in golang

Solution

Problem