[core] allow asset bundling on docker remote host / docker in docker

Core AssetStaging is now exposing a bundling option key allowing assets to be built before being uploaded through a docker image. Unfortunately the docker command is now using volume mount flags to mount input and output folder, making it impossible to execute if docker is set to run on a remote host or in a docker-in-docker env.

Use Case

I encountered this problem trying to build a couple of lambdas (and a custom resource provider) written in typescript on a Gitlab CI instance with docker-in-docker or executing docker commands via docker-machine.

Proposed Solution

My proposal is to create two temporary volumes on target docker env, one for inputs and one for outputs. Then the first volume can be filled running a busybox image as helper and calling docker cp to fill the volume. Once the cp has finished the helper is stopped and the build command is invoked. After that, if exit code is 0, another helper is started and the docker cp is used to copy outputs back to the cdk env.

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change

---

This is a 🚀 Feature Request

[pkasravi]

@AntonUspehov sure no problem!

name: CDK Deploy Pipeline
on:
  workflow_dispatch:
    inputs:
      deployEnv:
        description: "Deployment Environment (dev/prod)"
        required: true

jobs:
  Deploy:
    runs-on: ubuntu-20.04
    steps:
      - name: Checkout repository
        uses: actions/checkout@v2

      - name: Use Node.js
        uses: actions/setup-node@v2
        with:
          node-version: "14.15.1"

      - name: Install CDK
        run: |
          npm install -g aws-cdk

      - name: Use Python 3.8
        uses: actions/setup-python@v2
        with:
          python-version: "3.8"

      - name: Configure AWS Credentials
        uses: aws-actions/configure-aws-credentials@v1
        with:
          aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
          aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          aws-region: ${{ secrets.AWS_REGION }}

      - name: Run CDK Deploy
        run: |
          pip install -r requirements.txt
          cdk deploy my-stack

[katrinabrock]

@pkasravi yes!

I solved it by making cdk.out a mounted volume with the exact same path within the docker container as it is on the host.

https://github.com/katrinabrock/aws-cdk-dind-py-lambda/blob/master/docker-compose.yml#L8

I’m not sure if this is possible with github actions.