How to use custom packages

For this kind of folder structure:

main.go mylib/ mylib.go 

The simplest way is to use this:

import ( "./mylib" ) 

I am an experienced programmer, but, quite new into Go world ! And I confess I've faced few difficulties to understand Go... I faced this same problem when trying to organize my go files in sub-folders. The way I did it :

GO_Directory ( the one assigned to $GOPATH )

GO_Directory //the one assigned to $GOPATH __MyProject _____ main.go _____ Entites _____ Fiboo // in my case, fiboo is a database name _________ Client.go // in my case, Client is a table name 

On File MyProject\Entities\Fiboo\Client.go

package Fiboo type Client struct{ ID int name string } 

on file MyProject\main.go

package main import( Fiboo "./Entity/Fiboo" ) var TableClient Fiboo.Client func main(){ TableClient.ID = 1 TableClient.name = 'Hugo' // do your things here } 

( I am running Go 1.9 on Ubuntu 16.04 )

And remember guys, I am newbie on Go. If what I am doing is bad practice, let me know !

For a project hosted on GitHub, here's what people usually do：

github.com/ laike9m/ myproject/ mylib/ mylib.go ... main.go 

mylib.go

package mylib ... 

main.go

import "github.com/laike9m/myproject/mylib" ... 

I try so many ways but the best I use go.mod and put

module nameofProject.com 

and then i import from same project I use

import("nameofProject.com/folder") 

It's very useful to create project in any place

another solution:
add src/myproject to $GOPATH.

Then import "mylib" will compile.

finally I found the solution for this problem. Please note I have a very basic coding environment, also using basic stuff as I am a beginner at the moment. I wanted to use my library in the very same way as I use official libraries. I didn't have to edit GOPATH or any other system variables or paths, no need to rebuild or install anything. So here is my solution from top-down:

1. In my main package I have my code as follows:

 package main import ( "mylib" // This is my library!! "fmt" ) func main() { ... mylib.myFunc(par) mylib.myOtherFunc(par1,par2) ... } 

2. You have to use the very same package name in the package implementation files. My own package looks like as follows:

package mylib import ( "math" "strconv" "strings" ) func myFunc(par int) { ... } func myOtherFunc(par1 string, par2 int) { ... } 

3. What you have to keep in mind to name and place correctly all the stuff:

• Create a subfolder with the package name next to the other packages. You can find them easily by searchin eg. 'bufio', 'os' or 'math' (on my machine they are under \Go\src). In my case it looks like this:

   C: /Go /src /bufio /io /... /mylib /... /strings 

• Move your package file into this folder. The folder name is important, this has to be the same as the package name, this is how your compiler finds it

• You can have one ore more .go files here, they needn't to be named mylib.go, you can use any names, eg. myMath.go, myString.go, etc.

• I repeat: the package name in all the .go files has to be your library name ('mylib' in my case)

4. This way later on you can extend your own library by new functions, they can be implemented in separate .go files, the only important is you have to store this file in subfolder named 'mylib' and the package name has to be the same.

I hope it helps, best regards,

LA

For those who face this problem, you need to first initialize the go module before you can use custom package.

For example your code directory is: ../mycode/main.go. Now you want to create diffcode custom package and import it into main. You will first need to run the command go mod init mycode (make sure you are under ../mycode directory). Now you create package diffcode and it has some files. To import this package, you need to put this into main.go: module/package. In this case, mycode/diffcode.

The essential question here is to tailor the idea of compiling the package as library binary, and then import the binary code as third party library like "net/http" or "fmt" in some new go project, instead using the original go code. I am wondering if this is possible or not for go programming.

I recently started learning GO Lang and faced the same issue. It happens because many confuse themselves between module, package and file.

However, when I started the project, what I did was

go mod init <moduleName>

go mod init hello01 

or you can always look for the module name in go.mod file. mine looked like

module hello01 go 1.24.1 

and my package was in the relative folder, i.e., ./testPackage/test.go

which looked like

package test import "fmt" func MuFunc() { //Some Code Inside fmt.Println("Blah Blah Blah") } 

and my directory Looked Like somewhat

/project1 /testPackage test.go main.go go.mod 

So, I'll use my /testPackage for keeping my package, and main.go to implement those packages.

The main.go file looks like

package main import test "hello01/testPackage" func main() { test.MuFunc() } 

since my module name is hello01 and the package is in directory /testPackage, and because the name of the file is test.go I'm using function as test.Mufunc()

I hope this will help new commers. Exprienced Ones please rectify if any mistake was commited by me.