How to write data to local DynamoDB? - node.js

Question

According to DynamoDB docs, you always need to specify --endpoint-url http://localhost:8000 option if you want to interact with your local (downloaded) version of DynamoDB. It works fine for me via aws cli, but, following their tutorial for Node.js developers, I've faced a strange issue: I have been interacting with data in DynamoDB web version instead of my local one, even if configured connection options to database:
const serviceConfigOptions: ServiceConfigurationOptions = {
region: "eu-north-1",
endpoint: "http://localhost:8000",
};
I described endpoint, but I have no results interacting with data in my local version and I have these in the web.
All code is here:
import fs from "fs";
import AWS, { AWSError } from "aws-sdk";
import { config as dotenvConfig } from "dotenv";
import {
CreateTableInput,
DocumentClient,
PutItemInput,
PutItemOutput,
} from "aws-sdk/clients/dynamodb";
import { ServiceConfigurationOptions } from "aws-sdk/lib/service";
dotenvConfig();
const serviceConfigOptions: ServiceConfigurationOptions = {
region: "eu-north-1",
endpoint: "http://localhost:8000",
};
const dynamoDB: AWS.DynamoDB = new AWS.DynamoDB();
const params: CreateTableInput = {
TableName: "Movies",
KeySchema: [
{
AttributeName: "year",
KeyType: "HASH",
},
{
AttributeName: "title",
KeyType: "RANGE",
},
],
AttributeDefinitions: [
{ AttributeName: "year", AttributeType: "N" },
{ AttributeName: "title", AttributeType: "S" },
],
ProvisionedThroughput: {
ReadCapacityUnits: 10,
WriteCapacityUnits: 10,
},
};
dynamoDB.createTable(params, (err, data): void => {
if (err) {
console.log("Unable to create table.");
console.error(err);
return;
}
console.log("Table created");
console.log(data);
});
const docClient: DocumentClient = new AWS.DynamoDB.DocumentClient();
console.log("Imporing data to DynamoDB");
fs.readFile(
"moviedata.json",
"utf-8",
(err: NodeJS.ErrnoException | null, data: string): void => {
if (err) {
console.log("Unable to read a file");
console.error(err);
return;
}
const allMovies: Array<any> = JSON.parse(data);
allMovies.forEach(({ year, title, info }): void => {
const params: PutItemInput = {
TableName: "Movies",
Item: {
year,
title,
info,
},
};
docClient.put(params, (err: AWSError, data: PutItemOutput) => {
if (err) {
console.error(
"Unable to add movie",
title,
". Error JSON:",
JSON.stringify(err, null, 2),
);
return;
}
console.log("PutItem succeeded:", title);
});
});
},
);
UPDATE:
Refactored code into promises.
import fs from "fs";
import { promisify } from "util";
import AWS, { AWSError } from "aws-sdk";
import { config as dotenvConfig } from "dotenv";
import {
CreateTableInput,
DocumentClient,
PutItemInput,
PutItemOutput,
} from "aws-sdk/clients/dynamodb";
import { ServiceConfigurationOptions } from "aws-sdk/lib/service";
dotenvConfig();
const serviceConfigOptions: ServiceConfigurationOptions = {
region: "eu-north-1",
endpoint: "http://localhost:8000",
};
const dynamoDB: AWS.DynamoDB = new AWS.DynamoDB();
const params: CreateTableInput = {
TableName: "Movies",
KeySchema: [
{
AttributeName: "year",
KeyType: "HASH",
},
{
AttributeName: "title",
KeyType: "RANGE",
},
],
AttributeDefinitions: [
{ AttributeName: "year", AttributeType: "N" },
{ AttributeName: "title", AttributeType: "S" },
],
ProvisionedThroughput: {
ReadCapacityUnits: 10,
WriteCapacityUnits: 10,
},
};
const createDBTable: (
params: AWS.DynamoDB.CreateTableInput,
) => Promise<AWS.DynamoDB.CreateTableOutput> = promisify(
dynamoDB.createTable,
).bind(dynamoDB);
const readFile = promisify(fs.readFile);
createDBTable(params)
.then(data => {
console.log("Table created");
console.log(data);
})
.catch(err => {
console.log("Unable to create table.");
throw new Error(err);
})
.then(() => {
console.log("Imporing data to DynamoDB");
return readFile("moviedata.json", "utf-8");
})
.then((data: string) => {
const allMovies: Array<any> = JSON.parse(data);
const docClient: DocumentClient = new AWS.DynamoDB.DocumentClient();
allMovies.forEach(({ year, title, info }): void => {
const params: PutItemInput = {
TableName: "Movies",
Item: {
year,
title,
info,
},
};
docClient.put(params, (err: AWSError, data: PutItemOutput) => {
if (err) {
console.error(
"Unable to add movie",
title,
". Error JSON:",
JSON.stringify(err, null, 2),
);
return;
}
console.log("PutItem succeeded:", title);
});
});
})
.catch(err => {
console.error(err);
});
Now I'm getting Unable to create table. Error: ResourceInUseException: Table already exists: Movies. However, in my local db only one Music table.
$ aws dynamodb list-tables --endpoint-url http://localhost:8000
Out:
{
"TableNames": [
"Music"
]
}
P.S. AWS_SDK_LOAD_CONFIG=1

Answer 1

I found the mistake I made.
I've configured params
const serviceConfigOptions: ServiceConfigurationOptions = {
region: "eu-north-1",
endpoint: "http://localhost:8000",
};
but I forgot to pass it to const dynamoDB: AWS.DynamoDB = new AWS.DynamoDB(); as an argument.
Must be
const serviceConfigOptions: ServiceConfigurationOptions = {
region: "eu-north-1",
endpoint: "http://localhost:8000",
};
const dynamoDB: AWS.DynamoDB = new AWS.DynamoDB(serviceConfigOptions);