How to best send command line args to local dynamodb docker container

[dferretti]

Sorry if this is the wrong git repo - I couldn't find where the dockerfile for amazon/dynamodb-local was being maintained.

2 questions here:

1. Currently, to send command line args as described here https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBLocal.UsageNotes.html it looks like I need to send the full args to the java process instead of just the args to configure the dynamodb server. So instead of running docker run -it --rm amazon/dynamodb-local -sharedDb I need to run docker run -it --rm amazon/dynamodb-local -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb
   Would it be possible to change the entrypoint/cmd of the dockerfile to handle the java args for you and the user just pass in the extra arguments? I think the more common use case is to just specify the dynamodb args, but if a user wanted to modify the java args they should be able to override the entrypoint in their own docker run

2. What directory in the container should I mount if I want to persist the .db file?

[dferretti]

After some digging, I found the directory at /home/dynamodblocal, so to answer the second question, here is how I currently handle persisting my local dynamodb tables:

docker run -it --rm -v %cd%:/home/dynamodblocal/data -p 8000:8000 amazon/dynamodb-local -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb -dbPath ./data

[mrnickel]

I would also like to mirror @dferretti-fig 's request.

In my case I want to be able to augment my docker-compose.yml file to set the extra args

[pstephenson02]

I found this issue having the same question. Would be great if this were a bit easier to pass these args. Thanks!

[pstephenson02]

Just a note for anyone reading this as well: @dferretti-fig there is a typo in your comment above: The -jar parameter should be: -jar DynamoDBLocal.jar not -jar -DynamoDBLocal.jar 😎

[dferretti]

@pstephenson02 good catch - updated it in the comment 👍

[hounded]

Great work @dferretti-fig ! for those that want it I have created a docker-compose file off those findings

version: '3'

services:
  dynamo:
    image: amazon/dynamodb-local
    environment:
      - ./Djava.library.path=./DynamoDBLocal_lib
    ports:
      - "8000:8000"
    volumes:
      - <directory>:/home/dynamodblocal/data
    working_dir: /home/dynamodblocal
    command: ["-jar", "DynamoDBLocal.jar", "-sharedDb", "-dbPath", "./data"]

[alecdotico]

That didn't work for me. The /home/dynamodblocal/data folder is owned by root user, and the dynamodblocal user (which is running the service) cannot create the single databse file under it. This config worked for me:

version: '3'
services:
  dynamo:
    container_name: dynamodb
    image: amazon/dynamodb-local
    ports:
      - "8000:8000"
    volumes:
      - dynamodata:/home/dynamodblocal
    working_dir: /home/dynamodblocal
    command: "-jar DynamoDBLocal.jar -sharedDb -dbPath ."

[ashishsoni]

getting error
ERROR: Named volume "dynamodata:/home/dynamodblocal/data:rw" is used in service "dynamo" but no declaration was found in the volumes section.

[mycargus]

@ashishsoni If you want to use a custom volume based on alecdotico's config, add this to the bottom of your docker-compose config (likely docker-compose.yml):

volumes:
  dynamodata: {}

See https://docs.docker.com/compose/compose-file/#volumes

Hope that helps.

[amandarawls]

These are great solutions for Docker Compose -- however, I was looking for a solution that didn't use Docker Compose. Here is a Dockerfile solution.

    FROM amazon/dynamodb-local
    EXPOSE 8000/tcp
    WORKDIR /home/dynamodblocal
    VOLUME ["dynamodata:/home/dynamodblocal"]
    CMD ["-jar", "DynamoDBLocal.jar", "-sharedDb", "-dbPath", "."]

[cpaika]

@amandarawls Thanks for the solution! Much appreciated. Worked for us

[abagayev]

Hey, I've played with different solutions and posted the best one here, it works for me and my team:
https://github.com/abagayev/docker-bootstrap-collection/tree/master/dynamodb-local

Will update this page if anything change at amazon docker image.

[Luis-Palacios]

The docker-compose approach is very helpful, hopefully, we will get a way to easily pass the arguments via docker run

[jhughes2112]

Something like this works fine:
docker run -d --rm -p 8000:8000 amazon/dynamodb-local -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -inMemory

Just change the commands at the end to pass whatever you want to the docker image.