Did I do something wrong on importing a package under src?
My folder structure is like it:
- project
- src
helper.go( package utils)
main.go(package main)
And I want to use utils in the main.go
I write this:
import ("utils")
but give me the error,said can't import utils. I don't understand which is wrong. there is no other package under src.
Thank you for the help.
You must provide only 1 package within single folder. Consider to name package like the folder. In your case create folder "utils" and move your helper.go in there.
Please, don't forget to name public types, vars and funcs properly: start their names with uppercase symbol:
Finally your project would look like this:
Your helper.go would look like this:
package util
func SomeFunc() {
}
And your main.go would look like this:
package main
import "stackoverflowexamples/src/util"
func main(){
util.SomeFunc()
}
Related
Trying to import a file go file but unable to do so.
I have one main file:
main/
main.go
go_single_file.go
package main
import (
"./go_single_file"
)
func main() {
}
and go_single_file:
package go_single_file
func hello() bool{
return true
}
when i try to import go_single_file in my main file i get some sort of import error.
I am doing something wrong but not sure what.
If i make a separate package and import it then it works but not if it's in same folder.
Can anyone tell how can i import a go file from same folder.
In Golang files are organized into subdirectories called packages which enables code reusability.
The naming convention for Go package is to use the name of the directory where we are putting our Go source files. Within a single folder, the package name will be same for the all source files which belong to that directory.
I would recommend you to use go modules and your folders structure should be like this.
.
├── main.go
├── go.mod
├── go_single_file
│ └── go_single_file.go
In your go_single_file.go you are not using exported names for the function hello. So your file inside the go_single_file/go_single_file.go would look like this.
package go_single_file
func Hello() bool{
return true
}
Your main file would like this
package main
import (
"module_name/go_single_file"
)
func main() {
_ = go_single_file.Hello()
}
I'm tryng to create a custom package in go: i created folder project:
my_project
|_database
|_database.go
main.go
but when i try to import it gaves me this error: "could not import database (no package for import database)"
i try to run "go init" as written in some tutorial and created a "go.mod" file, then i run "go install" and works fine, but in the main.go it still not working.
The project structure is now this:
my_project
|_database
|_database.go
|_go.mod
|_go.sum
main.go
I work on windows with visual studio code
Here is how i import the package:
import (
"fmt"
...
"database"
)
function main() {
You need to do a few things.
Make sure your database.go is the following way:
it should contain a package name this case is database, comment the
function/s that need to be used outside this package, use func instead
of function. and comment code and capitalize function name so it can
be exported.
package database
import "fmt"
// Connect function to connect to my database
func Connect(){
fmt.Print("connected...")
}
your main.go should be the following.
use func instead of function, import database based on folder position
this case is ./ use the package name database. because this function
does not belong from current package main.
package main
import "./database"
func main() {
database.Connect()
}
This should be your folder structure.
my_project
|_database
|_database.go
main.go
go.mod
go.sum
I have a go Project with the following directory structure
utils(pkg)
| auth.go (has a function names test1)
controllers(pkg)
| login.go (has a function names test2)
I am trying to access function test1 from login.go. Here is what I have done
import "../utils"
func test2(c *gin.Context) bool{
utils.test1()
}
But I always get Unresolved reference test1. I am new to go . Can anyone help why I am getting this error?
No there is no relative import in Go.
you should use the absolute path considering GOPATH:
The GOPATH environment variable specifies the location of your workspace. It is likely the only environment variable you'll need to set when developing Go code. To get started, create a workspace directory and set GOPATH accordingly. see: https://golang.org/doc/code.html#GOPATH
Import paths
An import path is a string that uniquely identifies a package. A package's import path corresponds to its location inside a workspace
or in a remote repository (explained below).
The packages from the standard library are given short import paths
such as "fmt" and "net/http". For your own packages, you must choose a
base path that is unlikely to collide with future additions to the
standard library or other external libraries.
If you keep your code in a source repository somewhere, then you should use the root of that source repository as your base path. For
instance, if you have a GitHub account at github.com/user, that should
be your base path.
Note that you don't need to publish your code to a remote repository
before you can build it. It's just a good habit to organize your code
as if you will publish it someday. In practice you can choose any
arbitrary path name, as long as it is unique to the standard library
and greater Go ecosystem.
Example:
This example assumes you have set GOPATH=/goworkdir in your OS environment.
File: goworkdir/src/project1/utils/auth.go
package utils
func Test1() string {
return "Test1"
}
File: goworkdir/src/project1/controllers/login.go
package controllers
import "project1/utils"
func Test2() string {
return utils.Test1()
}
File: goworkdir/src/project1/main.go
package main
import (
"fmt"
"project1/controllers"
)
func main() {
fmt.Println(controllers.Test2())
}
Now if you go run main.go you should see output:
Test1
This is now different since the introduction of go modules, from go 1.11.
Thus, if you switch to go modules, and if your module is called "m", then the idiomatic way to do relative imports in your project tree would be to use: import "m/utils" and import "m/controllers" in places where you need to import those packages in your project.
For details, see:
https://github.com/golang/go/wiki/Modules#do-modules-work-with-relative-imports-like-import-subdir
GoLand users - by default these forms of imports appear as errors in the IDE. You need to enable Go Modules integration in settings
Here is another example project structure with file contents required to import correctly:
test1/
utils/
texts.go
main.go
go.mod
with following contents:
go.mod:
module mycompany.com/mytest
go 1.15
utils/texts.go (to make a function visible from a different package, it needs to start with an uppercase letter):
package utils
func GetText() string {
return "hello world"
}
main.go (only the full import name is supported, there is no shortcut to import from the same module easier):
package main
import (
"fmt"
"mycompany.com/mytest/test1/utils"
)
func main() {
fmt.Println(utils.GetText())
}
Given this directory configuration:
.
├── controllers
│ └── login.go
├── main.go
└── utils
└── auth.go
File main.go:
package main
import "./controllers"
func main() {
controllers.Test2("Hello")
}
File controllers/login.go:
package controllers
import "../utils"
func Test2(msg string) {
utils.Test1(msg)
}
File utils/auth.go:
package utils
import . "fmt"
func Test1(msg string) {
Println(msg)
}
Result works:
$ GO111MODULE=auto go build -o program main.go
$ ./program
Hello
So what you wanted to do works. The only difference is that I've used upper case function names, because it's required to export symbols.
I think you can just crate a vendor directory next to your source file, which acts like a relative GOPATH, and then create a relative symlink, which links to the package you want to import inside the vendor directory, and then import the package as if the vendor directory is your $GOPATH/src/.
It's possible as of Go 1.16, although still not as straightforward as it could be, by editing the go.mod file to resolve the package name to a relative path:
if you have a hello and a greeting packages side by side (hello contains main.go):
<home>/
|-- greetings/
|--go.mod <- init this as infra/greetings
|--greetings.go <- let's say that this package is called greetings
|-- hello/
|--go.mod <- init this as whatever/hello
|--main.go <- import infra/greetings
then edit hello's go.mod file and get the package:
go mod edit -replace infra/greetings=../greetings
go get infra/greetings
go mod tidy
There's a full example in the official documentation but hey, this might change again in the next version of Go.
Trying to wrap my head around packages in Golang.
This is my workspace
/bin
/pkg
/src
/github.com
/esbenp
/testrepo
/subpackage
somefuncs.go
main.go
main.go
package main
import "github.com/esbenp/testrepo/subpackage"
func main() {
Somefunc()
}
somefuncs.go
package subpackage
import "fmt"
func Somefunc() {
fmt.Printf("yo")
}
I was under the impression that since Somefunc starts with an uppercase letter it would be exported for use in other files that imported it. The ouput I get in the console is.
main.go:4: imported and not used: "github.com/esbenp/testrepo/subpackage"
main.go:8: undefined: Somefunc
Can someone point me in the right direction?
You have to prefix the function by the name of the package is belongs to: subpackage.Somefunc().
In the case you have several subpackages with the same name, you have to alias them while importing them, or there will be a conflict:
import (
xapi "x/xx/xxx/api"
yapi "y/yy/yyy/api"
)
When you import a package it will be made available under its name.
To address Somefunc in your main.go you have to do
subpackage.Somefunc()
my project organisation looks like this :
GOPATH
src
cvs/user/project
main.go
utils
utils.go
main.go looks like this :
package main
import (
"fmt"
"cvs/user/project/utils"
)
func main() {
...
utilsDoSomething()
...
}
and utils.go :
package utils
import (
"fmt"
)
func utilsDoSomething() {
...
}
The compiler tells me that :
main.go imported and not used: "cvs/user/project/utils"
main.go undefined: utilsDoSomething
I don't know what I'm doing wrong. Any idea would be helpful, thank you in advance !
You forgot the package prefix in main.go and your function is not exported, meaning it is not accessible from other packages. To export an identifier, use a capital letter at the beginning of the name:
utils.UtilsDoSomething()
Once you have the utils prefix you can also drop the Utils in the name:
utils.DoSomething()
If you want to import everything from the utils package into the namespace of your main application do:
import . "cvs/user/project/utils"
After that you can use DoSomething directly.
When you are referencing a function from a package you need to reference it using the package name.Function name (with capital case).
In your case use it as:
utils.UtilsDoSomething().
In Go the symbols (including function names) starting with lower case letters are not exported and so are not visible to other packages.
Rename the function to UtilsDoSomething.
If you strongly oppose exporting this function and you are using Go 1.5 or later, you can make your function visible to only your project by placing utils directory inside internal directory.
Specification of internal packages