Unable to write item(s) to DynamoDB table utilizing DocumentClient - Nodejs - node.js

Question

I'm absolutely brand new to DynamoDb and I'm trying to simply write an object from a NodeJS Lambda. Based on what I've read and researched I should probably be using DocumentClient from the aws-sdk. I also found the following question here regarding issues with DocumentClient, but it doesn't seem to address my specific issue....which I can't really find/pinpoint unfortunately. I've set up a debugger to help with SAM local development, but it appears to be only providing some of the errors.
The code's implementation is shown here.
var params = {
TableName: "March-Madness-Teams",
Item: {
"Id": {"S": randstring.generate(9)},
"School":{"S": team_name},
"Seed": {"S": seed},
"ESPN_Id": {"S": espn_id}
}
}
console.log(JSON.stringify(params))
dynamodb.put(params, (error,data) => {
if (error) {
console.log("Error ", error)
} else {
console.log("Success! ", data)
}
})
Basically I'm scrubbing a website utilizing cheerio library and cherry picking values from the DOM and saving them into the json object shown below.
{
"TableName": "March-Madness-Teams",
"Item": {
"Id": {
"S": "ED311Oi3N"
},
"School": {
"S": "BAYLOR"
},
"Seed": {
"S": "1"
},
"ESPN_Id": {
"S": "239"
}
}
}
When I attempt to push this json object to Dynamo, I get errors says
Error MultipleValidationErrors: There were 2 validation errors:
* MissingRequiredParameter: Missing required key 'TableName' in params
* MissingRequiredParameter: Missing required key 'Item' in params
The above error is all good in well....I assume it didn't like the fact that I had wrapped those to keys in strings, so I removed the quotes and sent the following
{
TableName: "March-Madness-Teams",
Item: {
"Id": {
"S": "ED311Oi3N"
},
"School": {
"S": "BAYLOR"
},
"Seed": {
"S": "1"
},
"ESPN_Id": {
"S": "239"
}
}
}
However, when I do that...I kind of get nothing.
Here is a larger code snippet.
return new Promise((resolve,reject) => {
axios.get('http://www.espn.com/mens-college-basketball/bracketology')
.then(html => {
const dynamodb = new aws.DynamoDB.DocumentClient()
let $ = cheerio.load(html.data)
$('.region').each(async function(index, element){
var preregion = $(element).children('h3,b').text()
var region = preregion.substr(0, preregion.indexOf('(') - 1)
$(element).find('a').each(async function(index2, element2){
var seed = $(element2).siblings('span.rank').text()
if (seed.length > 2){
seed = $(element2).siblings('span.rank').text().substring(0, 2)
}
var espn_id = $(element2).attr('href').split('/').slice(-2)[0]
var team_name = $(element2).text()
var params = {
TableName: "March-Madness-Teams",
Item: {
"Id": randstring.generate(9),
"School":team_name,
"Seed": seed,
"ESPN_Id": espn_id
}
}
console.log(JSON.stringify(params))
// dynamodb.put(params)
// .then(function(data) {
// console.log(`Success`, data)
// })
})
})
})
})

Answer 1

Can you try without the type?
Instead of
"School":{"S": team_name},
for example, use
"School": team_name,

Answer 2

From your code, I can see the mis promise on the dynamodb request. Try to change your lines :
dynamodb.put(params).then(function(data) {
console.log(`Success`, data)
})
to be :
dynamodb.put(params).promise().then(function(data) {
console.log(`Success`, data)
})
you can combine with await too :
await dynamodb.put(params).promise().then(function(data) {
console.log(`Success`, data)
})

Answer 3

exports.lambdaHandler = async (event, context) => {
const html = await axios.get('http://www.espn.com/mens-college-basketball/bracketology')
let $ = cheerio.load(html.data)
const schools = buildCompleteSchoolObject(html, $)
try {
await writeSchoolsToDynamo(schools)
return { statusCode: 200 }
} catch (error) {
return { statusCode: 400, message: error.message }
}
}
const writeSchoolsToDynamo = async (schools) => {
const promises = schools.map(async school => {
await dynamodb.put(school).promise()
})
await Promise.all(promises)
}
const buildCompleteSchoolObject = (html, $) => {
const schools = []
$('.region').each(loopThroughSubRegions(schools, $))
return schools
}
const loopThroughSubRegions = (schools, $) => {
return (index, element) => {
var preregion = $(element).children('h3,b').text()
var region = preregion.substr(0, preregion.indexOf('(') - 1)
$(element).find('a').each(populateSchoolObjects(schools, $))
}
}
const populateSchoolObjects = (schools, $) => {
return (index, element) => {
var seed = $(element).siblings('span.rank').text()
if (seed.length > 2) {
seed = $(element).siblings('span.rank').text().substring(0, 2)
}
var espn_id = $(element).attr('href').split('/').slice(-2)[0]
var team_name = $(element).text()
schools.push({
TableName: "March-Madness-Teams",
Item: {
"Id": randstring.generate(9),
"School": team_name,
"Seed": seed,
"ESPN_Id": espn_id
}
})
}
}
I know this is drastically different from what I started with but I did some more digging and kind of kind of worked to this...I'm not sure if this is the best way, but I seemed to get it to work...Let me know if something should change!

Answer 4

Oh I understand what you want.
Maybe you can see the code above works, but there is one concept you have to improve here about async - await and promise especially on lambda function.
I have some notes here from your code above, maybe can be your consideration to improve your lambda :
Using await for every promise in lambda is not the best approach because we know the lambda time limitation. But sometimes we can do that for other case.
Maybe you can change the dynamodb.put method to be dynamodb.batchWriteItem :
The BatchWriteItem operation puts or deletes multiple items in one or more tables.
Or If you have to use dynamodb.put instead, try to get improve the code to be like so :
const writeSchoolsToDynamo = async (schools) => {
const promises = schools.map(school => {
dynamodb.put(school).promise()
})
return Promise.all(promises)
}