Building Docker Image Failing with 'restart_process' extension on Windows

[djhelmick]

Tilt: v0.33.10, built 2023-12-15 System: windows-amd64

Beginning this afternoon, I've started seeing the below error when attempting to run my Tiltfile using the restart_process extension.

STEP 3/5 — Building Dockerfile: [***]
Building Dockerfile for platform linux/amd64:

  FROM tiltdev/restart-helper:2021-11-03 as restart-helper

  FROM localhost:63333/[***-tilt_docker_build_with_restart_base:tilt-612fc2746907dfe5
  RUN ["mkdir", "-p", "\tmp\.restart"]
  RUN ["touch", "/tmp/.restart/proc"]
  RUN ["chmod", "666", "/tmp/.restart/proc"]
  COPY --from=restart-helper /tilt-restart-wrapper /
  COPY --from=restart-helper /entr /
  ENTRYPOINT ["/tilt-restart-wrapper", "--watch_file=/tmp/.restart/proc", "dotnet", "[***.dll"]

     Building image
     [restart-helper 1/1] FROM docker.io/tiltdev/restart-helper:2021-11-03@sha256:74d89eac884107e73e2f947a72e702750c92b16e2fae3b1da1ac36c14e79c5ff
     [stage-1 1/6] FROM localhost:63333/[***-tilt_docker_build_with_restart_base:tilt-612fc2746907dfe5
     [stage-1 2/6] RUN ["mkdir", "-p", "\tmp\.restart"]
       → /bin/sh: 1: [mkdir,: not found

     ERROR IN: [stage-1 2/6] RUN ["mkdir", "-p", "\tmp\.restart"]

Build Failed: ImageBuild: process "/bin/sh -c [\"mkdir\", \"-p\", \"\\tmp\\.restart\"]" did not complete successfully: exit code: 127

I hadn't made any changes to the Tiltfile so at first I was at a bit of a loss as to why it suddenly started yelling about mkdir during this step. After looking through the repos, however, I noticed that the PR https://github.com/tilt-dev/tilt-extensions/pull/541 was accepted about an hour ago which adds in that RUN step.

I am running Tilt on Windows. I'm wondering if that call to os.path.dirname in the PR is maybe an issue because it returns a path containing backslashes on Windows instead of forward slashes? That windows-based path then tries to be used with mkdir during the dockerfile build, and it errors out there?

[nicks]

Hmmm that's odd. What are you using as a base image? The error doesn't have anything to do with Windows, it means you don't have 'mkdir' in the base image.

In any case, the PR has been rolled back

[djhelmick]

Hi @nicks , thank you! I've confirmed things are now working again after the rollback.

I'm not quite sure why the error manifests the way it does -- I agree it did initially look like mkdir was missing -- but the base image(s) from Tilt & basically any other that do for sure include mkdir lead to the same error if using a windows-based path that contains backslashes. And if you use a proper linux path instead with forward slashes, the error goes away.

I double-checked this just with a simple dockerfile that duplicates what the Tilt step was doing.

Not really an issue since it's been rolled back but just some more context if it's helpful!