Fails to parse Dockerfile base image when using stages

[harrymilne]

Problem

When envbuilder tries to build a Dockerfile that uses FROM <image> AS <stage> notation envbuilder errors parsing the base image

EXAMPLE 1

Dockerfile:

FROM public.ecr.aws/docker/library/python:3.10-slim AS base

Envbuilder error:

error: compile devcontainer.json: parse image from dockerfile: parse image ref "public.ecr.aws/docker/library/python:3.10-slim AS base": could not parse reference: public.ecr.aws/docker/library/python:3.10-slim AS base

EXAMPLE 2

Dockerfile:

FROM public.ecr.aws/docker/library/rust:1.73-bullseye@sha256:fbc99ade5c476a8d602192a1bf8d50ae3361469c160d55a34379905ad4f82ae5 as base

Envbuilder error:

error: compile devcontainer.json: get user from image: fetch image index.docker.io/library/base:latest: GET https://index.docker.io/v2/library/base/manifests/latest: UNAUTHORIZED: authentication required; [map[Action:pull Class: Name:library/base Type:repository]]

Solution

Envbuilder should understand the FROM <image> AS <stage> notation