docker build fails on macOS + colima

[Amar1729]

Background information

• Dendrite version or git SHA: v0.13.7
• SQLite3 or Postgres?: n/a
• Running in Docker?: yes
  • docker --version: Docker version 26.1.1, build 4cf5afaefa
  • colima --version: colima version 0.6.8
• go version: n/a
• Client used (if applicable): n/a

Description

• What is the problem: docker build fails on m1 (arm64) mac mini while using colima as a provider
• Who is affected: users trying to serve dendrite from an arm Mac
• How is this bug manifesting: (see steps to repro)
• When did this first appear:

Steps to reproduce

~/Documents/matrix/dendrite $ colima version
colima version 0.6.8
git commit: 9b0809d0ed9ad3ff1e57c405f27324e6298ca04f

runtime: docker
arch: aarch64
client: v26.1.1
server: v24.0.9

~/Documents/matrix/dendrite $ docker build -t matrixdotorg/dendrite-monolith .
DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
            Install the buildx component to build images with BuildKit:
            https://docs.docker.com/go/buildx/

Sending build context to Docker daemon  64.91MB
Step 1/23 : FROM --platform=${BUILDPLATFORM} docker.io/golang:1.21-alpine3.18 AS base
failed to parse platform : "" is an invalid component of "": platform specifier component must match "^[A-Za-z0-9_-]+$": invalid argument

However, there's a workaround: ssh into colima's VM, and then issue docker build from there.

$ colima ssh
amar@colima:/Users/amar/Documents/matrix/dendrite$ docker build -t matrixdotorg/dendrite-monolith .

<builds as expected>

I have deleted + re-initialized the colima VM to ensure i was building from a clean slate. I think that this actually might be some kind of an issue with how colima is setting certain variables, or communicating with the docker client. Since I figured out a workaround, i thought I would post it here in case anybody runs into the same issue (but I'm not yet sure why exactly this is happening?).

I did try docker build with --platform arm64 (and others) based on the error message, but that didn't result in anything different.