build: prepare release binaries

Compile static binaries for i386 and x86_64.

Use docker to simplify cross-compilation process.

.dockerignore

@@ -0,0 +1,15 @@
+.git/
+.gitignore
+
+.idea/
+
+.dockerignore
+Dockerfile
+
+cmd/mp707/mp707
+
+LICENSE
+README.md
+
+release/
+scripts/

.gitignore

@@ -1,7 +1,5 @@
-*
-!*/
-!**/*.go
-!go.mod
-!LICENSE
-!Makefile
-!README.md
+.idea/
+
+release/
+
+cmd/mp707/mp707

Dockerfile

@@ -0,0 +1,21 @@
+ARG FROM=golang:1.15-buster
+
+FROM $FROM as builder
+
+ARG DEVUAN_KEY=BB23C00C61FC752C
+
+# Debian's libudev-dev package doesn't include a static library (libudev.a) needed for static linking.
+# Fortunately we can install libeudev-dev package from Devuan repositories which provides udev-compatible
+# development files and a static library as well.
+RUN echo deb http://deb.devuan.org/merged ascii main > /etc/apt/sources.list.d/devuan.list
+RUN gpg --keyserver keys.gnupg.net --recv-key $DEVUAN_KEY && gpg -a --export $DEVUAN_KEY | apt-key add -
+
+RUN apt update && apt install --no-install-recommends -y libusb-1.0-0-dev libeudev-dev
+
+WORKDIR /go/mp707
+ADD . .
+RUN make static
+
+FROM scratch
+COPY --from=builder /go/mp707/cmd/mp707/mp707 /
+ENTRYPOINT ["/mp707"]

Makefile

@@ -1,8 +1,11 @@
+SLUG = $(shell head -1 go.mod | cut -d/ -f2-)
 NAME = mp707
 
 CGO_ENABLED = 1
 GO111MODULE = on
 
+export SLUG
+export NAME
 export CGO_ENABLED
 export GO111MODULE
 
@@ -25,6 +28,7 @@ test:
 .PHONY: clean
 clean:
  rm -vf cmd/$(NAME)/$(NAME)
+ rm -rvf release
 
 .PHONY: build
 build: cmd/$(NAME)/$(NAME)
@@ -35,3 +39,8 @@ static: build
 
 cmd/$(NAME)/$(NAME):
  cd cmd/$(NAME); go build -v -ldflags "$(LDFLAGS)"
+
+release: release/$(NAME).linux.386 release/$(NAME).linux.amd64
+
+release/$(NAME).linux.%:
+ GOARCH=$* OUTPUT=$@ scripts/release.sh

scripts/release.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+set -exo pipefail
+
+mkdir -p "$(dirname "$OUTPUT")"
+
+FROM=${FROM:-golang:1.15-buster}
+GOARCH=${GOARCH:amd64}
+
+DIGEST=$(docker manifest inspect "$FROM" | jq -r '.manifests[] | select(.platform.architecture == "'"$GOARCH"'") | .digest')
+FROM=$FROM@$DIGEST
+
+TAG=$SLUG:$GOARCH
+
+docker build \
+ --pull \
+ -t "$TAG" \
+ --build-arg FROM="$FROM" \
+ .
+
+CONTAINER=$(docker create "$TAG")
+
+docker cp "$CONTAINER":/"$NAME" "$OUTPUT"
+docker rm "$CONTAINER"