Sample script to scan DynamoDB table via AWS SDK for Go.

main.go

package main

import (
	"bytes"
	"encoding/json"
	"fmt"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/dynamodb"
	"github.com/aws/aws-sdk-go/service/dynamodb/dynamodbattribute"
)

// Thread is a struct of a Thread item
type Thread struct {
	ForumName          string   `dynamodbav:"ForumName" json:"forum_name"`
	Subject            string   `dynamodbav:"Subject" json:"subject"`
	Answered           int      `dynamodbav:"Answered" json:"answered"`
	LastPostedBy       string   `dynamodbav:"LastPostedBy" json:"last_posted_by"`
	LastPostedDateTime string   `dynamodbav:"LastPostedDateTime" json:"last_posted_date_time"`
	Message            string   `dynamodbav:"Message" json:"message"`
	Replies            int      `dynamodbav:"Replies" json:"replies"`
	Tags               []string `dynamodbav:"Tags" json:"tags"`
	Views              int      `dynamodbav:"Views" json:"views"`
}

// ThreadWithSomeAttr is a struct of a Thread item with some attributes.
type ThreadWithSomeAttr struct {
	ForumName string `dynamodbav:"ForumName" json:"forum_name"`
	Subject   string `dynamodbav:"Subject" json:"subject"`
}

var tableName string = "Thread"
var region string = "ap-northeast-1"
var db = dynamodb.New(session.New(), &aws.Config{
	Region: aws.String(region),
})

// Scan is a function to scan table.
func Scan() []Thread {
	var threads []Thread = []Thread{}
	scanOut, err := db.Scan(&dynamodb.ScanInput{
		TableName: aws.String(tableName),
	})

	if err != nil {
		fmt.Println(err.Error())
		return threads
	}

	for _, scanedThread := range scanOut.Items {
		var threadTmp Thread
		_ = dynamodbattribute.UnmarshalMap(scanedThread, &threadTmp)
		threads = append(threads, threadTmp)
	}

	return threads
}

// ScanSomeAttr is a function to scan table with some attributes.
func ScanSomeAttr() []ThreadWithSomeAttr {
	var threads []ThreadWithSomeAttr = []ThreadWithSomeAttr{}
	scanOut, err := db.Scan(&dynamodb.ScanInput{
		TableName: aws.String(tableName),
		ExpressionAttributeNames: map[string]*string{
			"#FNAME": aws.String("ForumName"),
			"#SUBJ":  aws.String("Subject"),
		},
		ProjectionExpression: aws.String("#FNAME, #SUBJ"),
	})

	if err != nil {
		fmt.Println(err.Error())
		return threads
	}

	for _, scanedThread := range scanOut.Items {
		var threadTmp ThreadWithSomeAttr
		_ = dynamodbattribute.UnmarshalMap(scanedThread, &threadTmp)
		threads = append(threads, threadTmp)
	}

	return threads
}

// ThreadsToJSONString is a function to convert Thread object to JSON string.
func ThreadsToJSONString(threads interface{}) string {
	j, err := json.Marshal(threads)

	if err != nil {
		fmt.Println(err.Error())
		return ""
	}

	var buf bytes.Buffer
	jerr := json.Indent(&buf, j, "", " ")

	if jerr != nil {
		fmt.Println(jerr.Error())
		return ""
	}

	return buf.String()
}

func main() {
	fmt.Println("Scan with all attributes.")
	allAttrRes := Scan()
	fmt.Println(ThreadsToJSONString(allAttrRes))

	fmt.Println("\nScan with some attributes.")
	someAttrRes := ScanSomeAttr()
	fmt.Println(ThreadsToJSONString(someAttrRes))
}