AWS DynamoDB

Component format

To setup a DynamoDB state store create a component of type state.aws.dynamodb. See this guide on how to create and apply a state store configuration.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
spec:
  type: state.aws.dynamodb
  version: v1
  metadata:
  - name: table
    value: "Contracts"
  - name: accessKey
    value: "AKIAIOSFODNN7EXAMPLE" # Optional
  - name: secretKey
    value: "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY" # Optional
  - name: endpoint
    value: "http://localhost:8080" # Optional
  - name: region
    value: "eu-west-1" # Optional
  - name: sessionToken
    value: "myTOKEN" # Optional
  - name: ttlAttributeName
    value: "expiresAt" # Optional
  - name: partitionKey
    value: "ContractID" # Optional
  # Uncomment this if you wish to use AWS DynamoDB as a state store for actors (optional)
  #- name: actorStateStore
  #  value: "true"

Primary Key

In order to use DynamoDB as a Dapr state store, the table must have a primary key named key. See the section Partition Keys for an option to change this behavior.

Spec metadata fields

Setup AWS DynamoDB

See Authenticating to AWS for information about authentication-related attributes

Time to live (TTL)

In order to use DynamoDB TTL feature, you must enable TTL on your table and define the attribute name. The attribute name must be defined in the ttlAttributeName field. See official AWS docs.

Partition Keys

By default, the DynamoDB state store component uses the table attribute name key as primary/partition key in the DynamoDB table. This can be overridden by specifying a metadata field in the component configuration with a key of partitionKey and a value of the desired attribute name.

To learn more about DynamoDB primary/partition keys, read the AWS DynamoDB Developer Guide.

The following statestore.yaml file shows how to configure the DynamoDB state store component to use the partition key attribute name of ContractID:

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: statestore
spec:
  type: state.aws.dynamodb
  version: v1
  metadata:
  - name: table
    value: "Contracts"
  - name: partitionKey
    value: "ContractID"

The above component specification assumes the following DynamoDB Table Layout:

{
    "Table": {
        "AttributeDefinitions": [
            {
                "AttributeName": "ContractID",
                "AttributeType": "S"
            }
        ],
        "TableName": "Contracts",
        "KeySchema": [
            {
                "AttributeName": "ContractID",
                "KeyType": "HASH"
            }
        ],
}

The following operation passes "A12345" as the value for key, and based on the component specification provided above, the Dapr runtime will replace the key attribute name with ContractID as the Partition/Primary Key sent to DynamoDB:

$ dapr run --app-id contractsprocessing --app-port ...

$ curl -X POST http://localhost:3500/v1.0/state/<store_name> \
  -H "Content-Type: application/json"
  -d '[
        {
          "key": "A12345",
          "value": "Dapr Contract"
        }
      ]'

The following AWS CLI Command displays the contents of the DynamoDB Contracts table:

$ aws dynamodb get-item \
    --table-name Contracts \
    --key '{"ContractID":{"S":"contractsprocessing||A12345"}}' 
{
    "Item": {
        "value": {
            "S": "Dapr Contract"
        },
        "etag": {
            "S": "....."
        },
        "ContractID": {
            "S": "contractsprocessing||A12345"
        }
    }
}

Workflow Limitations

The more complex a workflow is (number of activities, child workflows, etc.), the more state operations it performs per state store transaction. The maximum number of operations that can be performed by DynamoDB in a single transaction is 100. This means that DynamoDB can only handle workflows with a limited complexity, meaning it is not suitable for all workflow scenarios. A general guide to the number of records that are saved during a workflow executon can be found here.

Related links

• Basic schema for a Dapr component
• Read this guide for instructions on configuring state store components
• State management building block
• Authenticating to AWS