route method becomes undefined in main package file

Question

My code is as shown below :

app.go

package main

import (
    "github.com/go-martini/martini"
)

func main() {
    app := martini.Classic()

    app.Group("/books", func(r martini.Router) {

        r.Get("/:id", getBooks)
        r.Post("/new", newBook)
        r.Put("/update/:id", updateBook)
        r.Delete("/delete/:id", deleteBook)
    })

    app.RunOnAddr(":8080")
}

main.go

package main

import "github.com/go-martini/martini"

func getBooks() string {

    return "get books api called"
}

func newBook() string {
    return "Psot book api called"
}

func updateBook(params martini.Params) string {
    return "put api called " + params["id"]
}

func deleteBook(params martini.Params) string {
    return "delete api called " + params["id"]
}

But somehow when I run the code , it gives me the following error :

./app.go:16:17: undefined: getBooks ./app.go:17:18: undefined: newBook ./app.go:18:24: undefined: updateBook ./app.go:19:27: undefined: deleteBook

So is there any way to solve this problem?

the project structure is as follows:

goProject
---->app.go
---->main.go

Answer 1

There are two problems:

#1

You need to have both files in the same directory with the same package name; namely, main.

#2

You need to compile and execute all files in this directory which you can do either using:

• go run ./... to execute all files in this directory, or,

• go run app.go main.go to execute just these two files.

---

Alternatively, as suggested by @mkopriva, you can move and export all handler functions to a different package, let's call it package handlers and just import this package in your main app.