When using devcontainers in VSCode, I see that the command for building the image always includes the '--pull' directive.. But what if I want to use a fully local base image?.. What if I don't want it to be pulled and only use the locally cached one?
Is there a way to configure in devcontainer.json to tell it not to pull?
The way I solved it was using devcontainer.json's initializeCommand directive.
Use it to tag the local image with a new tag and use that as base in the Dockerfile, so there is no chance devcontainers will attempt to pull. If you use a tag that can be pulled, devcontainer seems to always use the pulled/remote one:
"initializeCommand": "docker build -t me/my_image:local ."
FROM me/my_image:local AS base
Alternatively you could use env vars to set the tag in different contexts
"initializeCommand": "TAG=local docker build -t my_image:local ."
FROM me/my_image:${TAG:-latest} AS base
And then, use other tags elsewhere or when you actually need the pulled image. Also, make sure to never push the local tag.