dynamodb golang query one Item
// +build examplepackage main
import (
// "flag"
"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"
"os"
"time"
)
func exitWithError(err error) {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
func main() {
cfg := Config{}
if err := cfg.Load(); err != nil {
exitWithError(fmt.Errorf("failed to load config, %v", err))
}
// Create the config specifiing the Region for the DynamoDB table.
// If Config.Region is not set the region must come from the shared
// config or AWS_REGION environment variable.
awscfg := &aws.Config{}
if len(cfg.Region) > 0 {
awscfg.WithRegion(cfg.Region)
}
// Create the session that the DynamoDB service will use.
sess, err := session.NewSession(awscfg)
if err != nil {
exitWithError(fmt.Errorf("failed to create session, %v", err))
}
// Create the DynamoDB service client to make the query request with.
svc := dynamodb.New(sess)
// Build the query input parameters
params := &dynamodb.ScanInput{
TableName: aws.String(cfg.Table),
}
if cfg.Limit > 0 {
params.Limit = aws.Int64(cfg.Limit)
}
fmt.Println("params is: ", params)
// Make the DynamoDB Query API call
result, err := svc.Scan(params)
if err != nil {
exitWithError(fmt.Errorf("failed to make Query API call, %v", err))
}
items := []Item{}
// Unmarshal the Items field in the result value to the Item Go type.
err = dynamodbattribute.UnmarshalListOfMaps(result.Items, &items)
if err != nil {
exitWithError(fmt.Errorf("failed to unmarshal Query result items, %v", err))
}
// Print out the items returned
for i, item := range items {
fmt.Printf("%d:UserID: %d, Time: %s Msg: %sCount: %d SecretKey:%s DeviceId: %s CampaginId:%s \n ", i, item.UserID, item.Time, item.Msg, item.Count, item.SecretKey, item.DeviceId, item.CampaginId)
//fmt.Printf("\tNum Data Values: %d\n", len(item.Data))
}
/* //1231241deviceid
params_del := &dynamodb.ScanInput{
TableName: aws.String(cfg.Table),
}
*/
//query oneItemdemo
params_get := &dynamodb.GetItemInput{
Key: map*dynamodb.AttributeValue{
"deviceid": {
S: aws.String("1231241"),
},
},
TableName: aws.String(cfg.Table), // Required
}
resp, err_get := svc.GetItem(params_get)
oneItem := Item{}
if err_get == nil {
// resp is now filled
fmt.Printf("resp type is %T \n ", resp.Item)
err = dynamodbattribute.UnmarshalMap(resp.Item, &oneItem)
if err == nil {
fmt.Printf("UserID: %d, Time: %s Msg: %sCount: %d SecretKey:%s DeviceId: %s CampaginId:%s \n ", oneItem.UserID, oneItem.Time, oneItem.Msg, oneItem.Count, oneItem.SecretKey, oneItem.DeviceId, oneItem.CampaginId)
} else {
fmt.Println(" Unmarshal err :", err)
}
//fmt.Println("convert to Struct objerr is ", err, "oneItem is:", oneItem)
} else {
fmt.Println("GetItem err is: ", err_get)
}
}
type Item struct {
UserID int // Hash key, a.k.a. partition key
Time time.Time // Range key, a.k.a. sort ke
Msg string `dynamo:"Message"`
Count int `dynamo:",omitempty"`
SecretKeystring `dynamo:"-"` // Ignored
DeviceId string `dynamo:"deviceid"`
CampaginId string `dynamo:"campid"`
}
type Config struct {
Tablestring // required
Region string // optional
Limitint64// optional
}
func (c *Config) Load() error {
//flag.Int64Var(&c.Limit, "limit", 0, "Limit is the max items to be returned, 0 is no limit")
//flag.StringVar(&c.Table, "table", "", "Table to Query on")
//flag.StringVar(&c.Region, "region", "", "AWS Region the table is in")
//flag.Parse()
c.Limit = 100
c.Region = "ap-southeast-1"
c.Table = "xxx_your_table_name"
if len(c.Table) == 0 {
// flag.PrintDefaults()
return fmt.Errorf("table name is required.")
}
return nil
}
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