DynamoDB with the AWS SDK for JavaScript v3

Uses @aws-sdk/client-dynamodb and @aws-sdk/lib-dynamodb 3.1160 with endpoint. The code is an ordinary application for the original database; nothing in it knows about MachNoSQL.

The only change

https://dynamodb.eu-central-1.amazonaws.com
https://machnosql.example.com:8000

The address comes from the environment variable DYNAMODB_ENDPOINT, so switching to MachNoSQL changes configuration only.

Run

export DYNAMODB_ENDPOINT='https://machnosql.example.com:8000'
npm install
npm start

Credentials are the usual AWS_ACCESS_KEY_ID / AWS_SECRET_ACCESS_KEY (an access key created in MachNoSQL) and AWS_REGION. Instead of passing the endpoint in code, current AWS SDKs and the AWS CLI also read AWS_ENDPOINT_URL_DYNAMODB from the environment; then the application needs no change at all.

Source

The program as it is kept and tested in the Mach Database NoSQL repository; highlighted lines read the connection setting.

app.js

// Orders table on DynamoDB, unchanged on MachNoSQL.
import { CreateTableCommand, DynamoDBClient, ResourceInUseException, waitUntilTableExists } from "@aws-sdk/client-dynamodb";
import {
  BatchWriteCommand,
  DynamoDBDocumentClient,
  GetCommand,
  QueryCommand,
  UpdateCommand,
} from "@aws-sdk/lib-dynamodb";

const client = new DynamoDBClient({ endpoint: process.env.DYNAMODB_ENDPOINT });
const docs = DynamoDBDocumentClient.from(client);

try {
  await client.send(
    new CreateTableCommand({
      TableName: "Orders",
      KeySchema: [
        { AttributeName: "customer", KeyType: "HASH" },
        { AttributeName: "orderId", KeyType: "RANGE" },
      ],
      AttributeDefinitions: [
        { AttributeName: "customer", AttributeType: "S" },
        { AttributeName: "orderId", AttributeType: "S" },
      ],
      BillingMode: "PAY_PER_REQUEST",
    }),
  );
  await waitUntilTableExists({ client, maxWaitTime: 60 }, { TableName: "Orders" });
} catch (error) {
  if (!(error instanceof ResourceInUseException)) throw error;
}

await docs.send(
  new BatchWriteCommand({
    RequestItems: {
      Orders: [
        { PutRequest: { Item: { customer: "ada", orderId: "1001", item: "keyboard", total: 49 } } },
        { PutRequest: { Item: { customer: "ada", orderId: "1002", item: "mouse", total: 39 } } },
        { PutRequest: { Item: { customer: "linus", orderId: "1003", item: "monitor", total: 199 } } },
      ],
    },
  }),
);

const { Item } = await docs.send(new GetCommand({ TableName: "Orders", Key: { customer: "ada", orderId: "1001" } }));
console.log(Item);

const { Items } = await docs.send(
  new QueryCommand({
    TableName: "Orders",
    KeyConditionExpression: "customer = :c",
    ExpressionAttributeValues: { ":c": "ada" },
  }),
);
console.log(Items);

await docs.send(
  new UpdateCommand({
    TableName: "Orders",
    Key: { customer: "ada", orderId: "1002" },
    UpdateExpression: "SET #s = :shipped",
    ConditionExpression: "attribute_not_exists(#s)",
    ExpressionAttributeNames: { "#s": "status" },
    ExpressionAttributeValues: { ":shipped": "shipped" },
  }),
);

package.json

{
  "name": "machnosql-example-dynamodb-node",
  "private": true,
  "type": "module",
  "scripts": { "start": "node app.js" },
  "dependencies": {
    "@aws-sdk/client-dynamodb": "^3.1160.0",
    "@aws-sdk/lib-dynamodb": "^3.1160.0"
  }
}