How do I use batchWriteItem with Node.js to query AWS DynamoDB? - node.js

Question

I'm new to AWS and I'm having problems trying to develop a simple Lambda function with Node.js. In DynamoDB, I have a table named Game with 3 attributes: gamepk, user, result.
In just one single execution of the Lambda function, I want to insert a collection of game elements (the number of elements in the collection could vary).
I had been reading some tutorials and it said I should use batchWriteItem, but because the collection of Game elements is variable I don't know how to proceed.
Could somebody write a function in Node.js that solves my problem?
An example of the JSON that the lambda function receives is this one:
{
"games": [{
"gamepk": "1",
"user": "rolo",
"result": "1-0"
},
{
"gamepk": "2",
"user": "jhon",
"result": "1-1"
}
]
}

Answer 1

This should get you what you need.
Create a New Lambda Function
Select Node Version 6
Select a Role or Create a New one that has DynamoDB Access to Write!
Open Created Function in the Web Console
Paste the Snippet Bellow into the Cloud 9 Editor
const AWS = require('aws-sdk/global');
exports.handler = (event, context, callback) => {
// The event parameter is the input to your lambda function
console.log(JSON.stringify(event));
let lambdaInput = event['PROPERTY_NAME_DEFINED_IN_POST'];
let games = [];
let documentClient = new AWS.DynamoDB.DocumentClient();
lambda.forEach(item => {
games.push({
PutRequest: {
Item: {
gamepk: item['gamepk'],
user: item['user'],
result: item['result']
}
}
});
});
let params = {
RequestItems: {
'TABLE_NAME': games
}
};
documentClient.batchWrite(params, function(err, data) {
if (err) {
callback(err);
} else {
callback(null, data);
}
});
}
Save the Function and then you are going to want to select the drop down at the top that says 'Select a Test Event' and then select 'Configure Test Events'.
This will open a new dialog, just save the JSON that is in the main text area and give the test a Name and Save it.
Now select that test that you just made from the 'Select a Test Event' drop down and then click 'Test' in the top right.
This documentation could be found at AWS Javascript SDK

Answer 2

As an additional help for the answer , you can use an environment variable and use it in the following way:
const MI_TABLE = process.env.MI_TABLE
let params = {
RequestItems: {
[ MI_TABLE ] : games
}
};
return await batchWrite(params);