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Amazon DynamoDB source

This event source captures changes to items stored in an Amazon DynamoDB Table by reading the time-ordered sequence of item-level modifications from a DynamoDB Stream.

With tmctl:

tmctl create source awsdynamodb --arn <arn> --auth.credentials.accessKeyID <keyID> --auth.credentials.secretAccessKey <key>

On Kubernetes:

apiVersion: sources.triggermesh.io/v1alpha1
kind: AWSDynamoDBSource
metadata:
  name: sample
spec:
  arn: arn:aws:dynamodb:us-west-2:123456789012:table/triggermeshtest

  auth:
    credentials:
      accessKeyID:
        valueFromSecret:
          name: awscreds
          key: aws_access_key_id
      secretAccessKey:
        valueFromSecret:
          name: awscreds
          key: aws_secret_access_key

  sink:
    ref:
      apiVersion: eventing.triggermesh.io/v1alpha1
      kind: RedisBroker
      name: triggermesh

Alternatively you can use an IAM role for authentication instead of an access key and secret, for Amazon EKS only:

auth:
  iamrole: arn:aws:iam::123456789012:role/foo

For details on authenticating with AWS, please take a look at our dedicated guide on AWS credentials.

Events produced have the following attributes:

See the Kubernetes object reference for more details.

Prerequisite(s)

  • DynamoDB Table and Stream
  • Amazon Resource Name (ARN)
  • API Credentials

DynamoDB Table and Stream

If you don't already have an Amazon DynamoDB Table, create one by following the instructions at Getting Started with DynamoDB. In order for change notifications to be consumed by the TriggerMesh Amazon DynamoDB event source, it is mandatory to enable a Stream on the DynamoDB Table. To do so, follow the instructions at Enabling a Stream. You are free to select the View type that is the most suitable for your own usage of the event source.

DynamoDB Table

Amazon Resource Name (ARN)

A fully qualified ARN is required to uniquely identify the Amazon DynamoDB Table.

This ARN can be obtained directly from the Overview tab after clicking the DynamoDB Table name in the list of existing tables. It typically has the following format:

arn:aws:dynamodb:{awsRegion}:{awsAccountId}:table/{tableName}

DynamoDB Table ARN

Alternatively, one can obtain the ARN of a DynamoDB Table by using the AWS CLI. The following command retrieves the information of a table called triggermeshtest in the us-west-2 region:

$ aws dynamodb describe-table --table-name triggermeshtest --region us-west-2
{
    "Table": {
        "TableName": "triggermeshtest",
        "TableStatus": "ACTIVE",
        "TableArn": "arn:aws:dynamodb:us-west-2:123456789012:table/triggermeshtest",
        (...)
    }
}

API Credentials

The TriggerMesh event source for Amazon DynamoDB authenticates calls to the AWS API using AWS Access Keys. The page Understanding and getting your AWS credentials contains instructions to create access keys when signed-in either as the root user or as an IAM user. Take note of the Access Key ID and Secret Access Key, they will be used to create an instance of the event source.

It is considered a good practice to create dedicated users with restricted privileges in order to programmatically access AWS services. Permissions can be added or revoked granularly for a given IAM user by attaching IAM Policies to it.

As an example, the following policy contains only the permissions required by the TriggerMesh Amazon DynamoDB event source to operate:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "dynamodb:ListStreams",
                "dynamodb:DescribeStream",
                "dynamodb:GetShardIterator",
                "dynamodb:GetRecords"
            ],
            "Resource": "arn:aws:dynamodb:*:*:*"
        }
    ]
}

Creating an IAM user