Add sample, stack and port to ARM64

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

contrib/golang/Dockerfile

+FROM debian:stretch
+
+RUN mkdir -p /usr/local/go
+ENV PATH=$PATH:/usr/local/go/bin
+RUN apt update && apt -qy install curl \
+ && curl -SL https://storage.googleapis.com/golang/go1.9.linux-arm64.tar.gz > go1.9.linux-arm64.tar.gz \
+ && tar -xvf go1.9.linux-arm64.tar.gz  -C /usr/local/go --strip-components=1
+
+RUN go version
+
+CMD ["/bin/sh"]

contrib/prometheus/Dockerfile

+FROM arm64v8/alpine:3.5
+
+workdir /root
+RUN apk add --update libarchive-tools
+
+ADD https://github.com/prometheus/prometheus/releases/download/v1.5.2/prometheus-1.5.2.linux-arm64.tar.gz /root/
+RUN bsdtar -xvf prometheus-*.tar.gz -C ./ --strip-components=1
+
+RUN mkdir -p /usr/share/prometheus
+RUN mkdir -p /etc/prometheus
+
+RUN cp prometheus                             /bin/prometheus
+RUN cp promtool                               /bin/promtool
+RUN cp prometheus.yml  /etc/prometheus/prometheus.yml
+RUN cp -r console_libraries/                     /usr/share/prometheus/console_libraries/
+RUN cp -r consoles/                              /usr/share/prometheus/consoles/
+
+#RUN ln -s /usr/share/prometheus/console_libraries /usr/share/prometheus/consoles/ /etc/prometheus/
+
+EXPOSE     9090
+VOLUME     [ "/prometheus" ]
+WORKDIR    /prometheus
+ENTRYPOINT [ "/bin/prometheus" ]
+CMD        [ "-config.file=/etc/prometheus/prometheus.yml", \
+             "-storage.local.path=/prometheus", \
+             "-web.console.libraries=/usr/share/prometheus/console_libraries", \
+             "-web.console.templates=/usr/share/prometheus/consoles" ]
+

docker-compose.arm64.yml

+version: "3.2"
+services:
+    gateway:
+        volumes:
+            - "/var/run/docker.sock:/var/run/docker.sock"
+        ports:
+            - 8080:8080
+        image: alexellis2/gateway:0.6.6-beta-arm64
+        networks:
+            - functions
+        environment:
+            dnsrr: "true"  # Temporarily use dnsrr in place of VIP while issue persists on PWD
+        deploy:
+            placement:
+                constraints:
+                    - 'node.role == manager'
+                    - 'node.platform.os == linux'
+    prometheus:
+        image: alexellis2/prometheus:1.5.2-arm64
+        command: "-config.file=/etc/prometheus/prometheus.yml -storage.local.path=/prometheus -storage.local.memory-chunks=10000 --alertmanager.url=http://alertmanager:9093"
+        ports:
+            - 9090:9090
+        depends_on:
+            - gateway
+            - alertmanager
+        environment:
+            no_proxy: "gateway"
+        networks:
+            - functions
+        deploy:
+            placement:
+                constraints:
+                    - 'node.role == manager'
+                    - 'node.platform.os == linux'
+
+networks:
+    functions:
+        driver: overlay
+        # Docker does not support this option yet - maybe create outside of the stack and reference as "external"?
+        #attachable: true

gateway/Dockerfile.arm64

+FROM alexellis2/golang:1.9-arm64 as build
+WORKDIR /go/src/github.com/alexellis/faas/gateway
+ENV GOPATH=/go
+
+COPY vendor         vendor
+
+COPY handlers       handlers
+COPY metrics        metrics
+COPY requests       requests
+COPY tests          tests
+
+COPY types          types
+COPY queue          queue
+COPY plugin         plugin
+COPY server.go      .
+
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o gateway .
+
+FROM debian:stretch
+WORKDIR /root/
+
+EXPOSE 8080
+ENV http_proxy      ""
+ENV https_proxy     ""
+
+COPY --from=build /go/src/github.com/alexellis/faas/gateway/gateway    .
+
+COPY assets     assets
+
+CMD ["./gateway"]

sample-functions/AlpineFunction/Dockerfile.arm64

+FROM arm64v8/alpine:3.6
+
+ADD https://github.com/alexellis/faas/releases/download/0.6.5/fwatchdog-arm64 /usr/bin/fwatchdog
+# COPY ./fwatchdog /usr/bin/
+RUN chmod +x /usr/bin/fwatchdog
+
+# Populate example here
+# ENV fprocess="wc -l"
+
+HEALTHCHECK --interval=5s CMD [ -e /tmp/.lock ] || exit 1
+CMD ["fwatchdog"]