dynamodb-admin-vperi-fork/lib/actions/purgeTable.js

GUI for DynamoDB. Useful for local development.

const { DescribeTableCommand } = require('@aws-sdk/client-dynamodb')
const { doSearch } = require('../util')

const findPrimaryKeys = context => {
  const params = {
    TableName: context.tableName
  }

  const DescribeTablePromise = context.dynamodbClient
    .send(new DescribeTableCommand(params))

  return DescribeTablePromise.then(tableDescription => {
    const tableSchema = tableDescription.Table.KeySchema

    context.primaryKeys = ['HASH', 'RANGE']
      .map(keyType => tableSchema.find(element => element.KeyType === keyType))
      .filter(attribute => attribute)
      .map(attribute => attribute.AttributeName)


    return context
  })
}

const findAllElements = context => {
  const ExpressionAttributeNames = {}

  for (const [index, key] of context.primaryKeys.entries()) {
    ExpressionAttributeNames[`#KEY${index}`] = key
  }

  const scanParams = {
    ExpressionAttributeNames,
    ProjectionExpression: Object.keys(ExpressionAttributeNames).join(', '),
  }

  return doSearch(context.dynamodbClient, context.tableName, scanParams)
    .then(items => {
      context.items = items
      return context
    })
}

const deleteAllElements = context => {
  const deleteRequests = []
  let counter = 0
  const MAX_OPERATIONS = 25
  const params = {
    RequestItems: {
      [context.tableName]: []
    }
  }

  for (const item of context.items) {
    params.RequestItems[context.tableName].push({
      DeleteRequest: {
        Key: item
      }
    })

    counter++

    if (counter % MAX_OPERATIONS === 0) {
      deleteRequests.push(context.dynamodb.batchWriteItem(params).promise())
      params.RequestItems[context.tableName] = []
    }
  }

  if (counter % MAX_OPERATIONS !== 0) {
    deleteRequests.push(context.dynamodb.batchWriteItem(params).promise())
    params.RequestItems[context.tableName] = []
  }

  return Promise.all(deleteRequests)
}

/**
 * This function deletes all record from a given table within dynamodb.
 *
 * It functions as follows:
 *  1) Determine the primary key of the table by calling describeTable
 *  2) Scan all records and store them in an array
 *  3) Pass the records to #deleteAllElements which in turn sends a delete request for each
 *  of them
 *  4) Return a list of promises using Promise.all() to the caller
 *
 * @param tableName the table we want to purge
 * @param dynamodb the AWS dynamodb service that holds the connection
 * @returns {Promise<any[] | never>} concatenation of all delete request promises
 */
const purgeTable = (tableName, dynamodbClient) => {
  const context = {
    tableName,
    dynamodbClient
  }

  return findPrimaryKeys(context)
    .then(findAllElements)
    .then(deleteAllElements)
}

module.exports = { purgeTable }