dynamo2es-lambda

Configurable AWS Lambda handler to index documents from DynamoDB Streams in Amazon Elasticsearch Service.

Installation

$ npm install dynamo2es-lambda

Usage

dynamo2es-lambda takes options object and returns AWS Lambda handler (using lambda-handler-as-promised) that is ready to be connected to any DynamoDB Stream. options object supports the following configuration options:

• index - { String } - Elasticsearch index to be used for all the documents; optional if indexField is provided
• type - { String } - Elasticsearch type to be used for all the documents; optional if typeField is provided
• [elasticsearch - alias: es] - { Object } - Elasticsearch configuration; under the hood library uses aws-elasticsearch-client; for more information check this documentation
  • [bulk] - { Object } - aside from general Elasticsearch configuration, you can use this field to pass additional parameters to bulk API
• [indexField] - { String | String[] } - field(s) to be used as an Elasticsearch index; if multiple fields are provided, values are concatenated using separator; required if indexPrefix field is present; can't be used together with index
• [indexPrefix] - { String } - static string to be used as a prefix to form index together with indexField value
• [typeField] - { String | String[] } - field(s) to be used as an Elasticsearch type; if multiple fields are provided, values are concatenated using separator; can't be used together with type
• [idField] - { String | String[] } - field(s) to be used as an Elasticsearch id; if multiple fields are provided, values are concatenated using separator [defaults to document's key field(s)]
• [versionField] - { String } - field to be used as an external version for Elasticsearch document [by default no version check is performed]
• [parentField] - { String } - field to be used as a parent id [no parent by default]
• [pickFields] - { String | String[] } - by default, the whole document is sent to Elasticsearch for indexing; if this option is provided, only field(s) specified would be sent
• [separator] - { String } - separator that is used to concatenate fields [defaults to '.']
• [beforeHook] - { Function(event, context) } - function to be called before any processing is done
• [afterHook] - { Function(event, context, result, meta) } - function to be called after all the processing is done; meta object contains parsed event data, action description and document that was indexed
• [recordErrorHook] - { Function(event, context, error) } - function to be called when error occurs while processing specific record; if hook is not provided, error is thrown and processing stops
• [errorHook] - { Function(event, context, error) } - function to be called when error occurs; if hook is not provided, error is thrown
• [retryOptions] - { Object } - retry configuration in case Elasticsearch indexing fails (options description can be found here) [is not retried by default]
• [transformRecordHook] - { Function(record) } - optional function to perform custom data processing; accepts single record, must return processed object; useful for reshaping document before sending it to Elasticsearch

Note: hooks provide convenient place to add custom logic, but they don't change workflow (except error hooks where you can define if error should be thrown)

Note: context object, available in hooks, includes all the context extensions provided by lambda-handler-as-promised

Note: afterHook and errorHook support asynchronous operations when logic is wrapped into Promise

Example

const d2es = require('dynamo2es-lambda');

module.exports.handler = d2es({
  elasticsearch: {
    hosts: 'your-aws-es-host.amazonaws.com',
    bulk: {
      refresh: 'wait_for'
    }
  },
  indexField: ['storeId', 'customerId'],
  type: 'type',
  idField: 'orderId',
  versionField: '_version',
  separator: '-',
  beforeHook: (event, context) => context.log.info({ event }),
  afterHook: (event, context, result) => {
    context.log.info({ result });
    if (result.errors) {
      /* error handling logic */
    }
  },
  errorHook: (event, context, err) => context.log.error({ err }),
  recordErrorHook: (event, context, err) => context.log.error({ err }),
  transformRecordHook: (record) => {
    return Object.assign({}, record, {fullName: `${record.firstName} ${record.lastName}`});
  }
});

Result Object

dynamo2es-lambda returns raw result provided by the bulk API:

"took": 123,
"errors": false,
"items": [
  {
    "index": {
      "_index": "08c312d0-9bd0-4a43-9748-9469f78e3ea0",
      "_type": "type",
      "_id": "f2f8cef2-031d-401f-a0c5-d6ce50a0bef3",
      "_version": 0,
      "result": "created",
      "_shards": {
          "total": 2,
          "successful": 2,
          "failed": 0
      },
      "created": true,
      "status": 201
    }
  }
]

Note: errors property is set to true only in case of critical errors (e.g. version conflict), but not for non-critical ones (e.g. not found).

License

The MIT License (MIT)

Copyright (c) 2016-2017 Anton Bazhal

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.