Add build-args to Dockerfile.armhf

When the /system/info endpoint was expanded to include information about the gateway a number of build-args were added to the main Dockerfile.  These changes were not mirrored in Dockerfile.armhf, which resulted in nil attributes and an ugly error when running `faas version` against an armhf gateway.

This change carries the changes made to Dockerfile through to Dockerfile.armhf.  As well as the build-args which fix the identified issue the license check has also been added at the latest release 0.2.3, as a armhf build has been made available.  Further changes are to introduce the app user and moving the binary location from /root/ to /home/app/

Signed-off-by: Richard Gee <richard@technologee.co.uk>

gateway/Dockerfile.armhf

 FROM golang:1.10.4 as build
+ARG GIT_COMMIT_SHA
+ARG GIT_COMMIT_MESSAGE
+ARG VERSION='dev'
+
+RUN curl -sSfL https://github.com/alexellis/license-check/releases/download/0.2.3/license-check-armhf \
+    > /usr/bin/license-check \
+    && chmod +x /usr/bin/license-check
 
 WORKDIR /go/src/github.com/openfaas/faas/gateway
 
@@ -16,17 +23,39 @@ COPY version        version
 COPY scaling        scaling
 COPY server.go      .
 
-RUN GOARM=7 CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o gateway .
+# Run a gofmt and exclude all vendored code.
+RUN license-check -path ./ --verbose=false "Alex Ellis" "OpenFaaS Project" "OpenFaaS Authors" "OpenFaaS Author(s)" \
+    && test -z "$(gofmt -l $(find . -type f -name '*.go' -not -path "./vendor/*"))" \
+    && go test $(go list ./... | grep -v integration | grep -v /vendor/ | grep -v /template/) -cover \
+    && GOARM=7 CGO_ENABLED=0 GOOS=linux go build --ldflags "-s -w \
+    -X github.com/openfaas/faas/gateway/version.GitCommitSHA=${GIT_COMMIT_SHA}\
+    -X \"github.com/openfaas/faas/gateway/version.GitCommitMessage=${GIT_COMMIT_MESSAGE}\"\
+    -X github.com/openfaas/faas/gateway/version.Version=${VERSION}" \
+    -a -installsuffix cgo -o gateway .
 
 FROM alpine:3.8
-WORKDIR /root/
+
+LABEL org.label-schema.license="MIT" \
+    org.label-schema.vcs-url="https://github.com/openfaas/faas" \
+    org.label-schema.vcs-type="Git" \
+    org.label-schema.name="openfaas/faas" \
+    org.label-schema.vendor="openfaas" \
+    org.label-schema.docker.schema-version="1.0"
+
+RUN addgroup -S app \
+    && adduser -S -g app app
+
+WORKDIR /home/app
 
 EXPOSE 8080
 ENV http_proxy      ""
 ENV https_proxy     ""
 
-COPY --from=0 /go/src/github.com/openfaas/faas/gateway/gateway    .
+COPY --from=build /go/src/github.com/openfaas/faas/gateway/gateway    .
 
 COPY assets     assets
-RUN sed -ie s/store.json/store-armhf.json/g /root/assets/script/funcstore.js
+RUN sed -ie s/store.json/store-armhf.json/g /home/app/assets/script/funcstore.js
+RUN chown -R app:app ./
+USER app
+
 CMD ["./gateway"]