Dockerfile-linux.template

{{
	def is_alpine:
		env.variant | startswith("alpine")
	;
	def alpine_version:
		env.variant | ltrimstr("alpine")
-}}
{{ if is_alpine then ( -}}
FROM alpine:{{ alpine_version }}

RUN apk add --no-cache ca-certificates

# set up nsswitch.conf for Go's "netgo" implementation
# - https://github.com/golang/go/blob/go1.9.1/src/net/conf.go#L194-L275
# - docker run --rm debian:stretch grep '^hosts:' /etc/nsswitch.conf
RUN [ ! -e /etc/nsswitch.conf ] && echo 'hosts: files dns' > /etc/nsswitch.conf
{{ ) else ( -}}
FROM buildpack-deps:{{ env.variant }}-scm

# install cgo-related dependencies
RUN set -eux; \
	apt-get update; \
	apt-get install -y --no-install-recommends \
		g++ \
		gcc \
		libc6-dev \
		make \
		pkg-config \
	; \
	rm -rf /var/lib/apt/lists/*
{{ ) end -}}

ENV PATH /usr/local/go/bin:$PATH

ENV GOLANG_VERSION {{ .version }}

{{
	def os_arches:
		if is_alpine then
			{
				amd64: "x86_64",
				arm32v6: "armhf",
				arm32v7: "armv7",
				arm64v8: "aarch64",
				i386: "x86",
				ppc64le: "ppc64le",
				s390x: "s390x",
			}
		else
			{
				amd64: "amd64",
				arm32v5: "armel",
				arm32v7: "armhf",
				arm64v8: "arm64",
				i386: "i386",
				mips64le: "mips64el",
				ppc64le: "ppc64el",
				s390x: "s390x",
			}
		end
-}}
RUN set -eux; \
{{ if is_alpine then ( -}}
	apk add --no-cache --virtual .fetch-deps gnupg; \
	arch="$(apk --print-arch)"; \
{{ ) else ( -}}
	arch="$(dpkg --print-architecture)"; arch="${arch##*-}"; \
{{ ) end -}}
	url=; \
	case "$arch" in \
{{
	[
		.arches | to_entries[]
		| select(.value.supported)
		| .key as $bashbrewArch
		| (
			os_arches
			| .[$bashbrewArch] // empty
		) as $osArch
		| .value
		| (
-}}
		{{ $osArch | @sh }}) \
{{ if .url and (is_alpine | not) then ( -}}
			url={{ .url | @sh }}; \
			sha256={{ .sha256 | @sh }}; \
{{ ) else ( -}}
			export {{ .env | to_entries | map(.key + "=" + (.value | @sh)) | join(" ") }}; \
{{ ) end -}}
			;; \
{{
		)
	] | add
-}}
		*) echo >&2 "error: unsupported architecture '$arch' (likely packaging update needed)"; exit 1 ;; \
	esac; \
	build=; \
	if [ -z "$url" ]; then \
# https://github.com/golang/go/issues/38536#issuecomment-616897960
		build=1; \
		url={{ .arches.src.url | @sh }}; \
		sha256={{ .arches.src.sha256 | @sh }}; \
{{ if is_alpine then ( -}}
# the precompiled binaries published by Go upstream are not compatible with Alpine, so we always build from source here 😅
{{ ) else ( -}}
		echo >&2; \
		echo >&2 "warning: current architecture ($arch) does not have a compatible Go binary release; will be building from source"; \
		echo >&2; \
{{ ) end -}}
	fi; \
	\
	wget -O go.tgz.asc "$url.asc"; \
	wget -O go.tgz "$url"{{ if is_alpine then "" else " --progress=dot:giga" end }}; \
	echo "$sha256 *go.tgz" | sha256sum -c -; \
	\
# https://github.com/golang/go/issues/14739#issuecomment-324767697
	GNUPGHOME="$(mktemp -d)"; export GNUPGHOME; \
# https://www.google.com/linuxrepositories/
	gpg --batch --keyserver keyserver.ubuntu.com --recv-keys 'EB4C 1BFD 4F04 2F6D DDCC  EC91 7721 F63B D38B 4796'; \
# let's also fetch the specific subkey of that key explicitly that we expect "go.tgz.asc" to be signed by, just to make sure we definitely have it
	gpg --batch --keyserver keyserver.ubuntu.com --recv-keys '2F52 8D36 D67B 69ED F998  D857 78BD 6547 3CB3 BD13'; \
	gpg --batch --verify go.tgz.asc go.tgz; \
	gpgconf --kill all; \
	rm -rf "$GNUPGHOME" go.tgz.asc; \
	\
	tar -C /usr/local -xzf go.tgz; \
	rm go.tgz; \
	\
	if [ -n "$build" ]; then \
{{ if is_alpine then ( -}}
		apk add --no-cache --virtual .build-deps \
			bash \
			gcc \
			go \
			musl-dev \
		; \
{{ if env.version == "1.18" then ( -}}
		if [ "$GOARCH" = 'ppc64le' ]; then \
# https://github.com/golang/go/issues/51787
			wget -O ppc64le-alpine.patch 'https://github.com/golang/go/commit/946167906ed8646c433c257b074a10e01f0a7dab.patch'; \
			apk add --no-cache --virtual .build-patch patch; \
			patch --strip=1 --input="$PWD/ppc64le-alpine.patch" --directory=/usr/local/go; \
			apk del --no-network .build-patch; \
			rm ppc64le-alpine.patch; \
		fi; \
{{ ) else "" end -}}
{{ ) else ( -}}
		savedAptMark="$(apt-mark showmanual)"; \
		apt-get update; \
		apt-get install -y --no-install-recommends golang-go; \
{{ ) end -}}
		\
		( \
			cd /usr/local/go/src; \
# set GOROOT_BOOTSTRAP + GOHOST* such that we can build Go successfully
			export GOROOT_BOOTSTRAP="$(go env GOROOT)" GOHOSTOS="$GOOS" GOHOSTARCH="$GOARCH"; \
			./make.bash; \
		); \
		\
{{ if is_alpine then ( -}}
		apk del --no-network .build-deps; \
{{ ) else ( -}}
		apt-mark auto '.*' > /dev/null; \
		apt-mark manual $savedAptMark > /dev/null; \
		apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
		rm -rf /var/lib/apt/lists/*; \
{{ ) end -}}
		\
# remove a few intermediate / bootstrapping files the official binary release tarballs do not contain
		rm -rf \
			/usr/local/go/pkg/*/cmd \
			/usr/local/go/pkg/bootstrap \
			/usr/local/go/pkg/obj \
			/usr/local/go/pkg/tool/*/api \
			/usr/local/go/pkg/tool/*/go_bootstrap \
			/usr/local/go/src/cmd/dist/dist \
		; \
	fi; \
	\
{{ if is_alpine then ( -}}
	apk del --no-network .fetch-deps; \
	\
{{ ) else "" end -}}
	go version

ENV GOPATH /go
ENV PATH $GOPATH/bin:$PATH
RUN mkdir -p "$GOPATH/src" "$GOPATH/bin" && chmod -R 777 "$GOPATH"
WORKDIR $GOPATH