Kohei Tokunaga has released Buildg – an interactive tool for debugging Dockerfiles. The motivation for the project is to provide an easy-to-use interactive tool to inspect this build process

Docker can build images automatically by reading the instructions from a Dockerfile. A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession.

A significant benefit of buildg allows developers to run container builds step-by-step, setting breakpoints in the process, and then be able to inspect the state of the build during these interim steps.

The application is based on BuildKit – the tool from the Moby Project for building and packaging software using containers which has been the core of “docker build” since Docker 18.09. Tokunaga has provided patches for BuildKit to support source-level debugging which have been accepted into that project.