copy-dynamodb-table.js

// source https://tvernon.tech/blog/move-dynamodb-data-between-regions
const AWS = require('aws-sdk')

// Use the scan method to get everything from the old table
const readAllDataFromTable = async ({ region, table }) => {
    AWS.config.update({ region })
    const documentClient = new AWS.DynamoDB.DocumentClient()
    const params = {
        TableName: table,
    };

    let scanResults = [];
    let items;
    do {
        items = await documentClient.scan(params).promise();
        items.Items.forEach((item) => scanResults.push(item));
        params.ExclusiveStartKey = items.LastEvaluatedKey;
    } while (typeof items.LastEvaluatedKey != "undefined");

    console.log(scanResults.length)
    return scanResults;
}

// Write one row of data to the new table
const writeRowToTable = async (db, table, row) => {
  return await new Promise((resolve, reject) => {
    db.put(
      {
        TableName: table,
        Item: row,
      },
      err => {
        if (err) {
          reject()
        } else {
          resolve()
        }
      }
    )
  })
}

// Write all the data to the new table
const writeDataToTable = async ({ region, table, data }) => {
  AWS.config.update({ region })
  const db = new AWS.DynamoDB.DocumentClient()

  // Keep a count of the successful writes so we can know if
  // all the items were written successfully
  let successfulWrites = 0

  await Promise.all(
    data.map(async item => {
      return new Promise(async resolve => {
        try {
          await writeRowToTable(db, table, item)
          successfulWrites++
        } catch (e) {
          // If something fails, log it
          console.log('error', e)
        }
        resolve()
      })
    })
  )

  console.log(`wrote ${successfulWrites} of ${data.length} rows to database`)
}

// Run the script
;(async function() {
  // Store all the data in memory to write later
  const data = await readAllDataFromTable({
    region: 'us-east-1',
    table: OLD_TABLE_NAME,
  })

  // Write the saved data to the new table
  await writeDataToTable({
    region: 'ap-south-1',
    table: NEW_TABLE_NAME,
    data,
  })
})()