feat: Add multi-platform support and experimental features to Docker build

.drone.yml

@@ -47,6 +47,8 @@ steps:
       registry: registry.coadcorp.com
       repo: registry.coadcorp.com/nathan/invertergui
       dockerfile: Dockerfile
+      platform: linux/amd64,linux/arm64
+      experimental: true
       buildx_options_semicolon: --platform=linux/amd64,linux/arm64;--provenance=false
       username: nathan
       password:
@@ -63,6 +65,8 @@ steps:
       registry: registry.coadcorp.com
       repo: registry.coadcorp.com/nathan/invertergui
       dockerfile: Dockerfile
+      platform: linux/amd64,linux/arm64
+      experimental: true
       buildx_options_semicolon: --platform=linux/amd64,linux/arm64;--provenance=false
       username: nathan
       password:
@@ -82,6 +86,8 @@ steps:
       registry: registry.coadcorp.com
       repo: registry.coadcorp.com/nathan/invertergui
       dockerfile: Dockerfile
+      platform: linux/amd64,linux/arm64
+      experimental: true
       buildx_options_semicolon: --platform=linux/amd64,linux/arm64;--provenance=false
       username: nathan
       password:

Dockerfile

@@ -1,9 +1,15 @@
-FROM golang:1.26-alpine as builder
+FROM --platform=$BUILDPLATFORM golang:1.26-alpine as builder
+
+ARG TARGETOS=linux
+ARG TARGETARCH
+ARG TARGETVARIANT
 
 RUN mkdir /build
 COPY . /build/
 WORKDIR /build
-RUN CGO_ENABLED=0 go build -o invertergui ./cmd/invertergui
+RUN set -eux; \
+    GOARM="${TARGETVARIANT#v}"; \
+    CGO_ENABLED=0 GOOS="${TARGETOS}" GOARCH="${TARGETARCH}" GOARM="${GOARM}" go build -o invertergui ./cmd/invertergui
 
 FROM scratch