Cloud Build docker build has a different build output to local docker build?

Question

I've run into a very strange issue where a Dockerfile is failing in one of it's steps when it's built on GCP Cloud Build.

However it builds locally just fine.

What might be the cause of the issue? Why would there by any difference?

The actual command that is failing to build is a npm build within the container.

Answer 1

Turned out to be a .env file that I had locally (but was not present in the repository due to a gitignore).