Serverless dynamodb local plugin

Usage no npm install needed!

<script type="module">
  import 0xcServerlessDynamodbLocal from 'https://cdn.skypack.dev/@0xc/serverless-dynamodb-local';


builds.sr.ht status License: MIT


This is a fork of the serverless-dynamodb-local package

This Plugin Requires

  • serverless@^1
  • Java Runtime Engine (JRE) version 6.x or newer


  • Install DynamoDB Local
  • Start DynamoDB Local with all the parameters supported (e.g port, inMemory, sharedDb)
  • Table Creation for DynamoDB Local

Install Plugin

npm install --save serverless-dynamodb-local

Then in serverless.yml add following entry to the plugins array: serverless-dynamodb-local

  - serverless-dynamodb-local

Using the Plugin

  1. Install DynamoDB Local sls dynamodb install

  2. Add DynamoDB Resource definitions to your Serverless configuration, as defined here: https://serverless.com/framework/docs/providers/aws/guide/resources/#configuration

  3. Start DynamoDB Local and migrate (DynamoDB will process incoming requests until you stop it. To stop DynamoDB, type Ctrl+C in the command prompt window). Make sure above command is executed before this. sls dynamodb start --migrate

Note: Read the detailed section for more information on advanced options and configurations. Open a browser and go to the url http://localhost:8000/shell to access the web shell for dynamodb local.

Install: sls dynamodb install

To remove the installed dynamodb local, run: sls dynamodb remove Note: This is useful if the sls dynamodb install failed in between to completely remove and install a new copy of DynamoDB local.

Start: sls dynamodb start

All CLI options are optional:

--port  		  -p  Port to listen on. Default: 8000
--cors                    -c  Enable CORS support (cross-origin resource sharing) for JavaScript. You must provide a comma-separated "allow" list of specific domains. The default setting for -cors is an asterisk (*), which allows public access.
--inMemory                -i  DynamoDB; will run in memory, instead of using a database file. When you stop DynamoDB;, none of the data will be saved. Note that you cannot specify both -dbPath and -inMemory at once.
--dbPath                  -d  The directory where DynamoDB will write its database file. If you do not specify this option, the file will be written to the current directory. Note that you cannot specify both -dbPath and -inMemory at once. For the path, current working directory is <projectroot>/node_modules/serverless-dynamodb-local/dynamob. For example to create <projectroot>/node_modules/serverless-dynamodb-local/dynamob/<mypath> you should specify -d <mypath>/ or --dbPath <mypath>/ with a forwardslash at the end.
--sharedDb                -h  DynamoDB will use a single database file, instead of using separate files for each credential and region. If you specify -sharedDb, all DynamoDB clients will interact with the same set of tables regardless of their region and credential configuration.
--delayTransientStatuses  -t  Causes DynamoDB to introduce delays for certain operations. DynamoDB can perform some tasks almost instantaneously, such as create/update/delete operations on tables and indexes; however, the actual DynamoDB service requires more time for these tasks. Setting this parameter helps DynamoDB simulate the behavior of the Amazon DynamoDB web service more closely. (Currently, this parameter introduces delays only for global secondary indexes that are in either CREATING or DELETING status.)
--optimizeDbBeforeStartup -o  Optimizes the underlying database tables before starting up DynamoDB on your computer. You must also specify -dbPath when you use this parameter.
--migration               -m  After starting dynamodb local, run dynamodb migrations.
--heapInitial                 The initial heap size
--heapMax                     The maximum heap size
--migrate                 -m  After starting DynamoDB local, create DynamoDB tables from the Serverless configuration.
--seed                    -s  After starting and migrating dynamodb local, injects seed data into your tables. The --seed option determines which data categories to onload.
--convertEmptyValues      -e  Set to true if you would like the document client to convert empty values (0-length strings, binary buffers, and sets) to be converted to NULL types when persisting to DynamoDB.

All the above options can be added to serverless.yml to set default configuration: e.g.

  # If you only want to use DynamoDB Local in some stages, declare them here
      - dev
      port: 8000
      inMemory: true
      heapInitial: 200m
      heapMax: 1g
      migrate: true
      seed: true
      convertEmptyValues: true
    # Uncomment only if you already have a DynamoDB running locally
    # noStart: true

Migrations: sls dynamodb migrate


In serverless.yml add following to execute all the migration upon DynamoDB Local Start

      migrate: true

AWS::DynamoDB::Table Resource Template for serverless.yml

      Type: AWS::DynamoDB::Table
        TableName: usersTable
          - AttributeName: email
            AttributeType: S
          - AttributeName: email
            KeyType: HASH
          ReadCapacityUnits: 1
          WriteCapacityUnits: 1

Note: DynamoDB local doesn't support TTL specification, therefore plugin will simply ignore ttl configuration from Cloudformation template.

Seeding: sls dynamodb seed


In serverless.yml seeding categories are defined under dynamodb.seed.

If dynamodb.start.seed is true, then seeding is performed after table migrations.

If you wish to use raw AWS AttributeValues to specify your seed data instead of Javascript types then simply change the variable of any such json files from sources: to rawsources:.

      seed: true

          - table: domain-widgets
            sources: [./domainWidgets.json]
          - table: domain-fidgets
            sources: [./domainFidgets.json]
          - table: users
            rawsources: [./fake-test-users.json]
          - table: subscriptions
            sources: [./fake-test-subscriptions.json]
> sls dynamodb seed --seed=domain,test
> sls dynamodb start --seed=domain,test

If seed config is set to true, your configuration will be seeded automatically on startup. You can also put the seed to false to prevent initial seeding to use manual seeding via cli.

    "id": "John",
    "name": "Doe",

Using DynamoDB Local in your code

You need to add the following parameters to the AWS NODE SDK dynamodb constructor

e.g. for dynamodb document client sdk

var AWS = require('aws-sdk');
new AWS.DynamoDB.DocumentClient({
    region: 'localhost',
    endpoint: 'http://localhost:8000',
    accessKeyId: 'DEFAULT_ACCESS_KEY',  // needed if you don't have aws credentials at all in env
    secretAccessKey: 'DEFAULT_SECRET' // needed if you don't have aws credentials at all in env

e.g. for dynamodb document client sdk

new AWS.DynamoDB({
    region: 'localhost',
    endpoint: 'http://localhost:8000',
    accessKeyId: 'DEFAULT_ACCESS_KEY',  // needed if you don't have aws credentials at all in env
    secretAccessKey: 'DEFAULT_SECRET' // needed if you don't have aws credentials at all in env


Using with serverless-offline plugin

When using this plugin with serverless-offline, it is difficult to use above syntax since the code should use DynamoDB Local for development, and use DynamoDB Online after provisioning in AWS. Therefore we suggest you to use serverless-dynamodb-client plugin in your code.

The serverless dynamodb start command can be triggered automatically when using serverless-offline plugin. Please note that you still need to install DynamoDB Local first.

Add both plugins to your serverless.yml file:

  - serverless-dynamodb-local
  - serverless-offline

Make sure that serverless-dynamodb-local is above serverless-offline so it will be loaded earlier.

Now your local DynamoDB database will be automatically started before running serverless offline.

Using with serverless-offline and serverless-webpack plugin

Run serverless offline start. In comparison with serverless offline, the start command will fire an init and a end lifecycle hook which is needed for serverless-offline and serverless-dynamodb-local to switch off both ressources.

Add plugins to your serverless.yml file:

  - serverless-webpack
  - serverless-dynamodb-local
  - serverless-offline #serverless-offline needs to be last in the list

Reference Project