Debian's Jonathan Dowland on bndcmpr and Dockerfile ARG footgun
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Jonathan Dowland: bndcmpr
(I also provided a Spotify playlist. Not all of the tracks in the playlist were available on Spotify, or Bandcamp.)
Since then I discovered an independent service bndcmpr which lets you build and share playlists from tracks hosted on Bandcamp.
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Jonathan Dowland: Dockerfile ARG footgun
This week I stumbled across a footgun in the Dockerfile/Containerfile
ARG
instruction.ARG
is used to define a build-time variable, possibly with a default value embedded in the Dockerfile, which can be overridden at build-time (by passing--build-arg
). The value of a variableFOO
is interpolated into any following instructions that include the token$FOO
.This behaves a little similar to the existing instruction
ENV
, which, forRUN
instructions at least, can also be interpolated, but can't (I don't think) be set at build time, and bleeds through to the resulting image metadata.