How to do it...

1. Create the project from the following template:

$ sls create --template-url https://github.com/danteinc/js-cloud-native-cookbook/tree/master/ch2/db-first-dynamodb --path cncb-db-first-dynamodb

2. Navigate to the cncb-db-first-dynamodb directory with cd cncb-db-first-dynamodb.
3. Review the file named serverless.yml with the following content:

service: cncb-db-first-dynamodb

provider:
  name: aws
  runtime: nodejs8.10
  iamRoleStatements:
    - Effect: Allow
      Action:
        - dynamodb:PutItem
      Resource:
        Fn::GetAtt: [ Table, Arn ]
    - Effect: Allow
      Action:
        - kinesis:PutRecord
      Resource: ${cf:cncb-event-stream-${opt:stage}.streamArn}

functions:
  command:
    handler: handler.command
    environment:
      TABLE_NAME:
        Ref: Table
  trigger:
    handler: handler.trigger
    events:
      - stream:
          type: dynamodb
          arn:
            Fn::GetAtt: [ Table, StreamArn ]
          ...
    environment:
      STREAM_NAME: ${cf:cncb-event-stream-${opt:stage}.streamName}

resources:
  Resources:
    Table:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: ${opt:stage}-${self:service}-things
        AttributeDefinitions:
          ...
        KeySchema:
          - AttributeName: id
            KeyType: HASH
        ...
        StreamSpecification:
          StreamViewType: NEW_AND_OLD_IMAGES

4. Review the file named handler.js with the following content:

module.exports.command = (request, context, callback) => {
  const thing = {
    id: uuid.v4(),
    ...request,
  };

  const params = {
    TableName: process.env.TABLE_NAME,
    Item: thing,
  };

  const db = new aws.DynamoDB.DocumentClient();
  db.put(params, callback);
};

module.exports.trigger = (event, context, cb) => {
  _(event.Records)
    .map(toEvent)
    .flatMap(publish)
    .collect()
    .toCallback(cb);
};

const toEvent = record => ({
  id: record.eventID,
  type: `thing-${EVENT_NAME_MAPPING[record.eventName]}`,
  timestamp: record.dynamodb.ApproximateCreationDateTime * 1000,
  partitionKey: record.dynamodb.Keys.id.S,
  tags: {
    region: record.awsRegion,
  },
  thing: {
    old: record.dynamodb.OldImage ?
      aws.DynamoDB.Converter.unmarshall(record.dynamodb.OldImage) :
      undefined,
    new: record.dynamodb.NewImage ?
      aws.DynamoDB.Converter.unmarshall(record.dynamodb.NewImage) :
      undefined,
  },
});

const EVENT_NAME_MAPPING = {
  INSERT: 'created',
  MODIFY: 'updated',
  REMOVE: 'deleted',
};

const publish = event => {
  const params = {
    StreamName: process.env.STREAM_NAME,
    PartitionKey: event.partitionKey,
    Data: Buffer.from(JSON.stringify(event)),
  };

  const kinesis = new aws.Kinesis();
  return _(kinesis.putRecord(params).promise());
}

5. Install the dependencies with npm install.
6. Run the tests with npm test -- -s $MY_STAGE.
   
7. Review the contents generated in the .serverless directory.
8. Deploy the stack:

$ npm run dp:lcl -- -s $MY_STAGE

> cncb-db-first-dynamodb@1.0.0 dp:lcl <path-to-your-workspace>/cncb-db-first-dynamodb
> sls deploy -r us-east-1 "-s" "john"

Serverless: Packaging service...
...
Serverless: Stack update finished...
...
functions:
  command: cncb-db-first-dynamodb-john-command
  trigger: cncb-db-first-dynamodb-john-trigger

9. Review the stack, functions, and table in the AWS Console.
10. Invoke the function with the following command:

$ sls invoke -r us-east-1 -f command -s $MY_STAGE -d '{"name":"thing one"}'

11. Take a look at the command function logs:

$ sls logs -f command -r us-east-1 -s $MY_STAGE
START ...
2018-04-17 00:29:13 ... request: {"name":"thing one"}
2018-04-17 00:29:13 ... params: {"TableName":"john-cncb-db-first-dynamodb-things","Item":{"id":"4297c253-f512-443d-baaf-65f0a36aaaa3","name":"thing one"}}
END ...
REPORT ... Duration: 136.99 ms    Billed Duration: 200 ms     Memory Size: 1024 MB    Max Memory Used: 35 MB    

12. Take a look at the trigger function logs:

$ sls logs -f trigger -r us-east-1 -s $MY_STAGE
START ...
2018-04-17 00:29:15 ... event: {"Records":[{"eventID":"39070dc13de0eb76548506a977d4134c","eventName":"INSERT",...,"dynamodb":{"ApproximateCreationDateTime":1523939340,"Keys":{"id":{"S":"4297c253-f512-443d-baaf-65f0a36aaaa3"}},"NewImage":{"name":{"S":"thing one"},"id":{"S":"4297c253-f512-443d-baaf-65f0a36aaaa3"}},"SequenceNumber":"100000000006513931753",...},...}]}
2018-04-17 00:29:15 ... {"id":"39070dc13de0eb76548506a977d4134c","type":"thing-created","timestamp":1523939340000,"partitionKey":"4297c253-f512-443d-baaf-65f0a36aaaa3","tags":{"region":"us-east-1"},"thing":{"new":{"name":"thing one","id":"4297c253-f512-443d-baaf-65f0a36aaaa3"}}}
2018-04-17 00:29:15 ... params: {"StreamName":"john-cncb-event-stream-s1","PartitionKey":"4297c253-f512-443d-baaf-65f0a36aaaa3","Data":{"type":"Buffer","data":[...]}}
2018-04-17 00:29:15 ... {"ShardId":"shardId-000000000000","SequenceNumber":"4958...3778"}
END ...
REPORT ... Duration: 326.99 ms    Billed Duration: 400 ms ... Max Memory Used: 40 MB    

13. Review the events collected in the data lake bucket.
14. Remove the stack once you have finished with npm run rm:lcl -- -s $MY_STAGE.