https://github.com/frantjc/dockerfile-addendum

Make Dockerfile's ADD function identically regardless of source.
https://github.com/frantjc/dockerfile-addendum

docker dockerfile go golang

Last synced: 17 days ago
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Make Dockerfile's ADD function identically regardless of source.

• Host: GitHub
• URL: https://github.com/frantjc/dockerfile-addendum
• Owner: frantjc
• License: mit
• Created: 2022-06-02T01:30:09.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2024-01-17T01:00:23.000Z (about 1 year ago)
• Last Synced: 2024-11-08T12:36:59.106Z (2 months ago)
• Topics: docker, dockerfile, go, golang
• Language: Go
• Homepage:
• Size: 225 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 6
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# dockerfile-ADDendum [![CI](https://github.com/frantjc/dockerfile-addendum/actions/workflows/ci.yml/badge.svg?branch=main&event=push)](https://github.com/frantjc/dockerfile-addendum/actions) [![godoc](https://pkg.go.dev/badge/github.com/frantjc/dockerfile-addendum.svg)](https://pkg.go.dev/github.com/frantjc/dockerfile-addendum) [![goreportcard](https://goreportcard.com/badge/github.com/frantjc/dockerfile-addendum)](https://goreportcard.com/report/github.com/frantjc/dockerfile-addendum) ![license](https://shields.io/github/license/frantjc/dockerfile-addendum)

Small script to pair with the Dockerfile `ADD` directive to make an idempotent action regardless of if the `` of the `ADD` is a local tar archive or a tar archive from a remote URL.

## use case

A Dockerfile's `ADD` directive is a bit [finicky](https://docs.docker.com/engine/reference/builder/#add). It allows files to be added to the image either from a local directory or a remote URL. This has value in that if the `` of the `ADD` is an `ARG`, then the functionality of the `ADD` can be changed with build-time arguments.

For example, this allows developers to lazily get the latest version of the dependency from a tar archive at some remote URL while CI consistently supplies the same tar archive to the Dockerfile as a `--build-arg`.

However, if that `` is expected to be either a local tar archive or a remote tar archive, the `ADD` directive is not idempotent; `ADD` unpacks local tar archives but not remote ones. As a result, subsequent Dockerfile directives would have to account for the difference to make the build successful.

This is where the ADDendum comes in:

## usage

```Dockerfile

FROM scratch

COPY --from=ghcr.io/frantjc/dockerfile-addendum /addendum /usr/local/bin

ARG tgz=zip_3.0_x86_64.tgz

ADD ${tgz} /tmp

RUN addendum -ruo /usr/local/bin /tmp/$(basename ${tgz})

```

Now this Dockerfile can be built with `--build-arg tgz=` where `` is either a tar archive at a remote URL or a local tar archive.