How to access a file from Docker image from the host using Google Clould Build

Question

I would like to move node_modules.zip which is inside the Docker image to the static folder found within the directory.

Currently, my cloudbuild.yaml looks as follows:

  - id: package_js
    name: gcr.io/numom-57642/test4:latest
    entrypoint: /bin/bash
    waitFor: ['-']
    args:
      - -c
      - |
        mv node_modules.zip static/

When I run cloud-build-local I get an error:

Step #1 - "package_js": mv: cannot stat 'node_modules.zip': No such file or directory

How can I access node_modules.zip which is part of the Docker Image.

Answer 1

Hmmm.... interesting.

I think you're on the right path.

You should be able to copy the file into the default mounted /workspace or a newly mounted volume:

- id: package_js
  name: gcr.io/numom-57642/test4:latest
  entrypoint: /bin/bash
  volumes:
  - name: 'scratch'
    path: '/scratch'
  args:
  - -c
  - |
    cp node_modules.zip /workspace
    cp node_modules.zip /scratch

And then:

- id: check
  name: busybox
  volumes:
  - name: 'scratch'
    path: '/scratch'
  args:
  - |
    ls -l /workspace
    ls -l /scratch

Using /workspace is easier as you needn't mount volumes but using /scratch is more explicit.