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I am not seeing an item in a DynamoDB Table after writing to it using the PutItemCommand. What am I doing wrong?

0

Lambda function code to write an item to DynamoDB Table named ‘weather’ // es6 syntax for including modules import * as fs from 'fs';

// es6 syntax for including modules
import {DynamoDB, PutItemCommand} from "@aws-sdk/client-dynamodb";

export const handler = async(event) => {

     console.log("entered handler function");

     const DDB = new DynamoDB({region: 'us-east-1'});
     let params = {};

     params.ReturnConsumedCapacity = "TOTAL";
     params.TableName = "weather";
     params.Item = {
    "sc": {
        "S": "Sacramento"
     },
     "t": {
        "N": "78"
     }
 };
 console.log(params);
 try {
     const response = DDB.send(new PutItemCommand(params));
 console.log("Success", response)
 } catch (err) {
     console.log("Error", err);
 }     
/*      
   setTimeout(function(){
       callback(null, "ok");
   }, 1000 * 10);
*/ 
};

Execution log from lambda function

Test Event Name seedDYnamoDB

Response null

Function Logs START RequestId: 5b04fd20-dbe6-4b8d-b4fa-93ad864d9a8f Version: $LATEST 2023-05-31T22:10:29.217Z 5b04fd20-dbe6-4b8d-b4fa-93ad864d9a8f INFO entered handler function 2023-05-31T22:10:29.555Z 5b04fd20-dbe6-4b8d-b4fa-93ad864d9a8f INFO { ReturnConsumedCapacity: 'TOTAL', TableName: 'weather', Item: { sc: { S: 'Sacramento' }, t: { N: '78' } } } 2023-05-31T22:10:29.557Z 5b04fd20-dbe6-4b8d-b4fa-93ad864d9a8f INFO Success Promise { <pending> } END RequestId: 5b04fd20-dbe6-4b8d-b4fa-93ad864d9a8f REPORT RequestId: 5b04fd20-dbe6-4b8d-b4fa-93ad864d9a8f Duration: 420.57 ms Billed Duration: 421 ms Memory Size: 128 MB Max Memory Used: 95 MB Init Duration: 471.46 ms

Request ID 5b04fd20-dbe6-4b8d-b4fa-93ad864d9a8f

It looks like it returned a pending Promise. I'm not sure what that means. I added the AWSLambdaBasicExecutionRole with PutItem Write access to the Permissions tab of the lambda function

Topics
ServerlessComputeDatabase
Tags
ServerlessAWS LambdaAmazon DynamoDB
Language
English
profile picture
albert21
asked a year ago872 views
3 Answers
3
Accepted Answer

You should await the response, as you don't, your Lambda container is getting shutdown too soon:

import {DynamoDB, PutItemCommand} from "@aws-sdk/client-dynamodb";
const DDB = new DynamoDB({region: 'us-east-1'});
export const handler = async(event) => {

     console.log("entered handler function");
     let params = {};

     params.ReturnConsumedCapacity = "TOTAL";
     params.TableName = "weather";
     params.Item = {
    "sc": {
        "S": "Sacramento"
     },
     "t": {
        "N": "78"
     }
 };
 console.log(params);
 try {
     // Added await to the DDB promise returned.
     const response =  await DDB.send(new PutItemCommand(params));
     console.log("Success", response)
 } catch (err) {
     console.log("Error", err);
 }     
/*      
   setTimeout(function(){
       callback(null, "ok");
   }, 1000 * 10);
*/ 
};

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

profile pictureAWS
EXPERT
Leeroy Hannigan
answered a year ago
  • albert21
    a year ago

    I get the following error after adding the await keyword.

    `Test Event Name seedDYnamoDB

    Response { "errorType": "Runtime.UserCodeSyntaxError", "errorMessage": "SyntaxError: Unexpected reserved word", "trace": [ "Runtime.UserCodeSyntaxError: SyntaxError: Unexpected reserved word", " at _loadUserApp (file:///var/runtime/index.mjs:994:17)", " at async UserFunction.js.module.exports.load (file:///var/runtime/index.mjs:1032:21)", " at async start (file:///var/runtime/index.mjs:1195:23)", " at async file:///var/runtime/index.mjs:1201:1" ] }`

  • Leeroy Hannigan EXPERT
    a year ago

    Can you share the code you are running, i'm guessing its different to what you previously shared?

  • albert21
    a year ago

    I just shared the updated code below.

1

Hi, following page will explain you how to use promises with DDB in order to manage its asynchronous responses.

https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/using-promises.html

So, if you properly process the returned promise, you should be able to see your item after it gets written

profile pictureAWS
EXPERT
Didier_Durand
answered a year ago
-1

I've attached the code I'm currently working on below. I commented out some code I am playing around with that I can get to successfully write to the DynamoDB table 'weather'. The code is below the ``// USING DynamoDBCLient, DynamoDBDocumentClient, and PutCommand`

I don't understand why I am getting the ** "errorType": "Runtime.UserCodeSyntaxError", "errorMessage": "SyntaxError: Unexpected reserved word",** error message after adding the await keyword in front of the DDB.send function call in the second section of the code below the ``// USING DynamoDB and PutItemCommand This code reads items from a csv file and uses a try/catch block to call the DDB.send function to write to the DynamoDB table 'weather'

UPDATE: Fixed the SyntaxError by adding async keyword to innermost function. I also rewrote the code in ES6 arrow function format. However, the original problem comes back in which the items don't get written to the DynamoDB table. I know I've done something wrong, but I've looked at it for hours and still no luck. See updated code below.

// es6 syntax for including modules
import * as fs from 'fs';

// es6 syntax for including modules
import {DynamoDB, PutItemCommand, DynamoDBClient} from "@aws-sdk/client-dynamodb";
import { PutCommand, DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb";

export const handler = async(event) => {
     console.log("entered handler function");

//      
// USING DynamoDBCLient, DynamoDBDocumentClient,  and PutCommand 
//
/*     const DDB = new DynamoDBClient({region: 'us-east-1'});
     const docClient = DynamoDBDocumentClient.from(DDB);
     let params = {};
     const command = new PutCommand({
        "TableName": 'weather',
        "ReturnConsumedCapacity": "TOTAL",
        "Item": {
 //         "sc": {"S": "Sacramento" } ,
          "sc": "Sac",
          "t" : "74"
        }
    });
    const response = await docClient.send(command);
    console.log(response);
    return(response);*/

//      
// USING DynamoDB and PutItemCommand
//
     const DDB = new DynamoDB({region: 'us-east-1'});
     let params = {};
     const fileContents = fs.readFileSync("cities.csv", "utf8").split('\n').map(function(item_str){
          params.ReturnConsumedCapacity = "TOTAL";
          params.TableName = "weather";
          params.Item = {
              "sc": {
                  "S": item_str.split(",")[0]
              },
              "t": {
                  "N": String(item_str.split(",")[1])
              }
          };
          console.log(params);
          try {
              const responses = await DDB.send(new PutItemCommand(params));
              console.log("Success", responses)
          } catch (err) {
              console.log("Error", err);
          }
      });

/*      
   setTimeout(function(){
       callback(null, "ok");
   }, 1000 * 10);
  */
};

UPDATED CODE

// es6 syntax for including modules
import * as fs from 'fs';

// es6 syntax for including modules
import {DynamoDB, PutItemCommand, DynamoDBClient} from "@aws-sdk/client-dynamodb";

import { PutCommand, DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb";

export const handler = async(event, callback) => {

     console.log("entered handler function");

     const DDB = new DynamoDBClient({region: 'us-east-1'});
     const docClient = DynamoDBDocumentClient.from(DDB);
     let params = {};

     const fileContents = fs.readFileSync("cities.csv", "utf8").split('\n').map(async (item_str) => {
          params.ReturnConsumedCapacity = "TOTAL";
          params.TableName = "weather";
          params.Item = {
              "sc": {
                  "S": item_str.split(",")[0]
              },
              "t": {
                  "N": String(item_str.split(",")[1])
              }
          };
          console.log(params);
          try {
              const responses = await docClient.send(new PutCommand(params));
              console.log(responses);
              return(responses);
          } catch (err) {
              console.log("Error", err);
          } finally {
              console.log("Success");
          }
      });
      
   setTimeout(function(){
       callback(null, "ok");
   }, 1000 * 10);
  
};

Execution Log

Test Event Name
seedDYnamoDB

Response
null

Function Logs
'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'CATHEDRAL CITY' }, t: { N: '39' } }
}
2023-06-06T20:43:41.064Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'ELKHART' }, t: { N: '45' } }
}
2023-06-06T20:43:41.064Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'FONTANA' }, t: { N: '31' } }
}
2023-06-06T20:43:41.065Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'LINCOLN' }, t: { N: '57' } }
}
2023-06-06T20:43:41.065Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'MACON' }, t: { N: '38' } }
}
2023-06-06T20:43:41.121Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'MARYSVILLE' }, t: { N: '73' } }
}
2023-06-06T20:43:41.121Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'MEMPHIS' }, t: { N: '44' } }
}
2023-06-06T20:43:41.122Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'MESA' }, t: { N: '66' } }
}
2023-06-06T20:43:41.122Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'MYRTLE BEACH' }, t: { N: '44' } }
}
2023-06-06T20:43:41.122Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'NAPERVILLE' }, t: { N: '61' } }
}
2023-06-06T20:43:41.122Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'PANAMA CITY' }, t: { N: '28' } }
}
2023-06-06T20:43:41.122Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'PATERSON' }, t: { N: '77' } }
}
2023-06-06T20:43:41.123Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'POMPANO BEACH' }, t: { N: '38' } }
}
2023-06-06T20:43:41.123Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'SABANA' }, t: { N: '67' } }
}
2023-06-06T20:43:41.123Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'SAN BUENAVENTURA' }, t: { N: '50' } }
}
2023-06-06T20:43:41.123Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'SANTA ROSA' }, t: { N: '41' } }
}
2023-06-06T20:43:41.123Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'SARASOTA' }, t: { N: '43' } }
}
2023-06-06T20:43:41.241Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'SIOUX CITY' }, t: { N: '60' } }
}
2023-06-06T20:43:41.261Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'SOUTH BEND' }, t: { N: '52' } }
}
2023-06-06T20:43:41.301Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'SPRINGDALE' }, t: { N: '41' } }
}
2023-06-06T20:43:41.302Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'ST. PETERSBURG' }, t: { N: '44' } }
}
2023-06-06T20:43:41.302Z	5ed80d11-17a2-4300-a11e-4a41afebd8a1	INFO	{
  ReturnConsumedCapacity: 'TOTAL',
  TableName: 'weather',
  Item: { sc: { S: 'WEST COVINA' }, t: { N: '69' } }
}
END RequestId: 5ed80d11-17a2-4300-a11e-4a41afebd8a1
REPORT RequestId: 5ed80d11-17a2-4300-a11e-4a41afebd8a1	Duration: 2556.87 ms	Billed Duration: 2557 ms	Memory Size: 128 MB	Max Memory Used: 35 MB

Request ID
5ed80d11-17a2-4300-a11e-4a41afebd8a1
profile picture
albert21
answered a year ago
  • albert21
    a year ago

    Adding an await Promise.all( in front of the fs.readFileSync function call seemed to do the trick.

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