golang: Deleting all items in Dynamo DB with a full scan

delete_jobs.go

package main

import (
	"fmt"
	"strconv"

	"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"
)

const (
	TableName = "jobs"
	KeyName   = "jobId"
	Region    = "ap-southeast-2"
)

func getNextJobsPage(db *dynamodb.DynamoDB, exclusiveStartKey map[string]*dynamodb.AttributeValue) (*dynamodb.ScanOutput, error) {
	var queryInput = &dynamodb.ScanInput{
		TableName:         aws.String(TableName),
		Select:            aws.String("ALL_ATTRIBUTES"),
		Limit:             aws.Int64(100),
		ExclusiveStartKey: exclusiveStartKey,
	}

	fmt.Println("Fetching. LastKey: %v\n", exclusiveStartKey)
	return db.Scan(queryInput)
}

func deleteJob(db *dynamodb.DynamoDB, jobID *string) error {
	key := make(map[string]*dynamodb.AttributeValue)
	key[KeyName] = &dynamodb.AttributeValue{
		N: jobID,
	}
	var deleteQuery = &dynamodb.DeleteItemInput{
		TableName:                   aws.String(TableName),
		Key:                         key,
		ReturnValues:                aws.String("NONE"),
		ReturnConsumedCapacity:      aws.String("NONE"),
		ReturnItemCollectionMetrics: aws.String("NONE"),
	}

	_, err := db.DeleteItem(deleteQuery)

	return err
}

func main() {
	sesh := session.New(&aws.Config{
		Region: aws.String(Region),
	})

	db := dynamodb.New(sesh)

	var lastEvaluatedKey map[string]*dynamodb.AttributeValue
	lastEvaluatedKey = nil

	for {
		result, _ := getNextJobsPage(db, lastEvaluatedKey)
		for _, i := range result.Items {
			item := Job{}
			err := dynamodbattribute.UnmarshalMap(i, &item)

			if err != nil {
				fmt.Printf("Job %d failed to unmarshal. Error %s", item.JobID, err.Error())
			}

			id := strconv.Itoa(item.JobID)
			fmt.Printf("Deleting job %s\n", id)
			if err = deleteJob(db, &id); err != nil {
				panic(err)
			}
		}

		if result.LastEvaluatedKey == nil {
			break
		}

		lastEvaluatedKey = result.LastEvaluatedKey
	}
}