From 14de6776022966723097ec2cad212fceea6cf859 Mon Sep 17 00:00:00 2001
From: Chris Banks <chris.banks@digital.cabinet-office.gov.uk>
Date: Tue, 14 May 2024 12:48:27 +0100
Subject: [PATCH] Run arm64 builds natively.

In principle we could just cross-build from a single runner, but it's
less hassle to just do the same thing we do for the Ruby builds where we
don't cross-compile.
---
 Dockerfile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index a167fb5..a69130b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,7 @@ ARG go_version=1.22
 ARG go_tag_suffix=-alpine
 
 
-FROM ${go_registry}golang:${go_version}${go_tag_suffix} AS builder
+FROM --platform=$TARGETPLATFORM $${go_registry}golang:${go_version}${go_tag_suffix} AS builder
 ARG TARGETARCH TARGETOS
 ARG GOARCH=$TARGETARCH GOOS=$TARGETOS
 ARG CGO_ENABLED=0
@@ -16,7 +16,7 @@ COPY . ./
 RUN go build -o /bin/govuk-exporter main.go
 
 
-FROM scratch
+FROM --platform=$TARGETPLATFORM $scratch
 COPY --from=builder /bin/govuk-exporter /bin/govuk-exporter
 COPY --from=builder /usr/share/ca-certificates /usr/share/ca-certificates
 COPY --from=builder /etc/ssl /etc/ssl