Add docker cross-compile for arm64

This makes use of the docker buildx to cross-compile images for amd64/arm64. It is worth noting that there are ongoing issues with the Go compiler and qemu (used by buildx/buildkit) and the solution I ended up using here was to limit the affinity to `go build`. Better solutions may be forthcoming.

Refs:
https://github.com/golang/go/issues/24656
https://bugs.launchpad.net/qemu/+bug/1696773

This relates to issue #11 regarding container images built for running on Raspberry Pi.

Dockerfile

@@ -11,19 +11,19 @@ COPY cmd cmd/
 COPY internal internal/
 COPY public public/
 
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GO111MODULE=on go build -a -o q3 ./cmd/q3
+RUN CGO_ENABLED=0 GOOS=linux GO111MODULE=on taskset -c 1 /usr/local/go/bin/go build -a -o q3 ./cmd/q3
 
 FROM alpine:3.12 as quake-n-bake
 
-RUN apk add --no-cache git gcc make libc-dev sdl2-dev mesa-dev
+RUN apk add --no-cache git gcc make libc-dev
 RUN git clone https://github.com/ioquake/ioq3
-RUN cd /ioq3 && make
+RUN cd /ioq3 && make BUILD_MISSIONPACK=0 BUILD_BASEGAME=0 BUILD_CLIENT=0 BUILD_SERVER=1 BUILD_GAME_SO=0 BUILD_GAME_QVM=0 BUILD_RENDERER_OPENGL2=0
-RUN cp /ioq3/build/release-linux-x86_64/ioq3ded.x86_64 /usr/local/bin/ioq3ded
+RUN cp /ioq3/build/release-linux-$(uname -m)/ioq3ded.$(uname -m) /usr/local/bin/ioq3ded
 
 FROM alpine:3.12
 
 COPY --from=builder /workspace/q3 /usr/local/bin
 COPY --from=quake-n-bake /usr/local/bin/ioq3ded /usr/local/bin
-COPY --from=quake-n-bake /lib/ld-musl-x86_64.so.1 /lib
+COPY --from=quake-n-bake /lib/ld-musl-*.so.1 /lib
 
 ENTRYPOINT ["/usr/local/bin/q3"]

Makefile

@@ -9,9 +9,13 @@ q3: gen
 gen: ## Generate and embed templates
 	@go run tools/genstatic.go public public
 
-VERSION ?= v1.0.2
+VERSION ?= v1.0.3
 IMAGE   ?= docker.io/criticalstack/quake:$(VERSION)
 
 .PHONY: build
 build:
 	@docker build . --force-rm --build-arg GOPROXY --build-arg GOSUMDB -t $(IMAGE)
+
+.PHONY: buildx
+buildx:
+	@docker buildx build . --platform=linux/amd64,linux/arm64 --progress=auto -t $(IMAGE) --push

README.md

@@ -122,6 +122,17 @@ The easiest way to develop quake-kube is building the binary locally with `make`
 $ bin/q3 server -c config.yaml --assets-dir $HOME/.q3a --agree-eula
 ```
 
+### Multi-platform images
+
+Container images are being cross-compiled with [Docker Buildx](https://docs.docker.com/buildx/working-with-buildx/) so it can run on hardware with different architectures and operating systems. Currently, it is building for `linux/amd64` and `linux/arm64`. While not specifically compiling to the macOS platform (`darwin/amd64`) QuakeKube should also work on macOS and maybe even Windows. This is due to the fact that they both use a linux VM to provide container support.
+
+Docker Buildx uses [QEMU](https://www.qemu.org/) to virtualize non-native platforms, which has unfortunately had long-running issues running the Go compiler:
+
+* [golang/go#24656](https://github.com/golang/go/issues/24656)
+* [https://bugs.launchpad.net/qemu/+bug/1696773](https://bugs.launchpad.net/qemu/+bug/1696773)
+
+This issue is circumvented by ensuring that the Go compiler does not run across multiple hardware threads, which is why the affinity is being limited in the Dockerfile.
+
 ## Credits
 
 * [inolen/quakejs](https://github.com/inolen/quakejs) - The really awesome QuakeJS project that makes this possible.

example.yaml

@@ -22,7 +22,7 @@ spec:
         - --config=/config/config.yaml
         - --content-server=http://localhost:9090
         - --agree-eula
-        image: docker.io/criticalstack/quake:v1.0.2
+        image: docker.io/criticalstack/quake:v1.0.3
         name: server
         ports:
         - containerPort: 8080
@@ -40,7 +40,7 @@ spec:
         - q3
         - content
         - --seed-content-url=http://content.quakejs.com
-        image: docker.io/criticalstack/quake:v1.0.2
+        image: docker.io/criticalstack/quake:v1.0.3
         name: content-server
         ports:
         - containerPort: 9090

internal/quake/server/server.go

@@ -22,14 +22,17 @@ var (
 		Name: "quake_active_players",
 		Help: "The current number of active players",
 	})
+
 	scores = promauto.NewGaugeVec(prometheus.GaugeOpts{
 		Name: "quake_player_scores",
 		Help: "Current scores by player, by map",
 	}, []string{"player", "map"})
+
 	pings = promauto.NewGaugeVec(prometheus.GaugeOpts{
 		Name: "quake_player_pings",
 		Help: "Current ping by player",
 	}, []string{"player"})
+
 	configReloads = promauto.NewCounter(prometheus.CounterOpts{
 		Name: "quake_config_reloads",
 		Help: "Config file reload count",
@@ -97,6 +100,7 @@ func (s *Server) Start(ctx context.Context) error {
 		}
 		tick := time.NewTicker(5 * time.Second)
 		defer tick.Stop()
+
 		for {
 			select {
 			case <-tick.C:
@@ -107,7 +111,9 @@ func (s *Server) Start(ctx context.Context) error {
 				}
 				actrvePlayers.Set(float64(len(status.Players)))
 				for _, p := range status.Players {
-					scores.WithLabelValues(p.Name, status.Configuration["mapname"]).Set(float64(p.Score))
+					if mapname, ok := status.Configuration["mapname"]; ok {
+						scores.WithLabelValues(p.Name, mapname).Set(float64(p.Score))
+					}
 					pings.WithLabelValues(p.Name).Set(float64(p.Ping))
 				}
 			case <-ctx.Done():