External Modules

Using AWS SDK V2

In the AWS SDK you will often have to convert a string to a string pointer. For that we can use the “String” function of “github.com/aws/aws-sdk-go-v2/aws”.

Create programm with external module

mkdir moremodules
cd moremodules
go mod init moremodules

Output:

go: creating new go.mod: module moremodules

Create a main.go:

vi main.go

  1 package main
  2
  3 import (
  4         "fmt"
  5         "github.com/aws/aws-sdk-go-v2/aws"
  6 )
  7
  8 func main() {
  9   aStringPointer := aws.String("Hi")
 10   fmt.Println(aStringPointer)
 11   fmt.Println(*aStringPointer)
 12 }

package main

import (
	"fmt"

	"github.com/aws/aws-sdk-go-v2/aws"
)

func main() {
	aStringPointer := aws.String("Hi")
	fmt.Println(aStringPointer)
	fmt.Println(*aStringPointer)
}

In line 5 we reference and import the github repository “https://github.com/aws/aws-sdk-go-v2".

Run

When we run the the programm:

go run main.go

We get the error

main.go:6:2: no required module provides package github.com/aws/aws-sdk-go-v2/aws; to add it:
	go get github.com/aws/aws-sdk-go-v2/aws

To use the module we have to get it. There are several ways to do this:

	go get github.com/aws/aws-sdk-go-v2/aws

To just get this single module, or:

go mod tidy

To get all modules:

Output:

go: finding module for package github.com/aws/aws-sdk-go-v2/aws
go: found github.com/aws/aws-sdk-go-v2/aws in github.com/aws/aws-sdk-go-v2 v1.9.0

The referenced modules are also stored in the file go.mod:

 cat go.mod
module moremodules

go 1.17

require github.com/aws/aws-sdk-go-v2 v1.9.0

require github.com/aws/smithy-go v1.8.0 // indirect

Run again

go run main.go

Output:

0xc000190cb0
Hi

In the first line the adress the string pointer points to is shown and in the second line we tell fmt.Println with the * to interpret the variable as a string pointer, which shows the string content.

See also