amazon-web-servicesdockerdocker-composeamazon-dynamodbamazon-dynamodb-local

Create DynamoDB table in Docker Compose

I'm using Docker Compose for testing to replicate my AWS infrastructure which uses CloudFormation. My CloudFormation template create a FooBars DynamoDB table and I want to do the same for my Docker Compose setup.

I add a DynamoDB Local service:

  foobar-service-db:
    image: amazon/dynamodb-local:latest
    command: "-jar DynamoDBLocal.jar -inMemory"
    ports: [8090:8000]
    restart: always

When I run docker compose … I can then use aws dynamodb create-table to create a table using --endpoint-url http://localhost:8090 and --region dummy-region. Great. I want to do that as part of Docker Compose, so I add this "service":

  foobar-service-db-init:
    depends_on:
      - foobar-service-db
    image: amazon/aws-cli
    environment:
      AWS_ACCESS_KEY_ID: dummy-key-id
      AWS_SECRET_ACCESS_KEY: dummy-key
    command: >-
      dynamodb create-table
          --table-name FooBars
          --attribute-definitions
              AttributeName=id,AttributeType=S
          --key-schema
              AttributeName=id,KeyType=HASH
          --billing-mode PAY_PER_REQUEST
          --endpoint-url http://foobar-service-db:8000 --region dummy-region

(Note that I have to indicate the container port instead of the host port, because the request is inside the Docker Compose network.)

I can see the output when Docker Compose starts up, and it shows that a table with an ARN of arn:aws:dynamodb:ddblocal:000000000000:table/FooBars was created. But when I try aws dynamodb list-tables --endpoint-url http://localhost:8090 --region dummy-region from the command line, no tables are listed.

However on the command line I can create the table using aws dynamodb create-table … --endpoint-url http://localhost:8090 --region dummy-region, which should be equivalent what foobar-service-db-init is calling. This command also says is created a table with ARN arn:aws:dynamodb:ddblocal:000000000000:table/FooBars was created. And if I run the same command again, it says "Cannot create preexisting table" as expected.

So foobar-service-db-init inside Docker Compose seems to be creating the table somewhere else, where it doesn't show up when I make the request from the command line. But where else could it be creating it? There is only one DynamoDB Local service, foobar-service-db!

(From the command line I'm using my actual AWS credentials. But that shouldn't make a difference. Surely DynamoDB Local doesn't have a separate namespace based on user identity—that's not how it works on AWS itself. The namespace is based on region, and I specify the same dummy-region.)

Solution

  • Try using -sharedDb:

    command: "-jar DynamoDBLocal.jar -inMemory -sharedDb"