add versioning

Dockerfile

@@ -1,7 +1,9 @@
 # Build container
 FROM golang:alpine AS buildstage
 
-RUN mkdir /cloudflared
+ARG CLOUDFLARED_TAG
+
+RUN mkdir -p /root-layer/cloudflared
 WORKDIR /src
 
 RUN apk --no-cache add git build-base curl jq
@@ -9,26 +11,30 @@ RUN apk --no-cache add git build-base curl jq
 ENV GO111MODULE=on \
     CGO_ENABLED=0
 
-RUN curl -s https://api.github.com/repos/cloudflare/cloudflared/releases/latest \
-  | jq -rc ".tag_name" \
-  | xargs -I TAG sh -c 'git -c advice.detachedHead=false clone https://github.com/cloudflare/cloudflared --depth=1 --branch TAG .'
+RUN \
+  if [ -z "${CLOUDFLARED_TAG}" ]; then \
+    curl -s https://api.github.com/repos/cloudflare/cloudflared/releases/latest \
+      | jq -rc ".tag_name" \
+      | xargs -I TAG sh -c 'git -c advice.detachedHead=false clone https://github.com/cloudflare/cloudflared --depth=1 --branch TAG .'; \
+  else \
+    git -c advice.detachedHead=false clone https://github.com/cloudflare/cloudflared --depth=1 --branch ${CLOUDFLARED_TAG} .; \
+  fi
 
 RUN GOOS=linux GOARCH=amd64 make cloudflared
-RUN mv cloudflared /cloudflared/cloudflared-amd64
+RUN mv cloudflared /root-layer/cloudflared/cloudflared-amd64
 
 RUN GOOS=linux GOARCH=arm64 make cloudflared
-RUN mv cloudflared /cloudflared/cloudflared-arm64
+RUN mv cloudflared /root-layer/cloudflared/cloudflared-arm64
 
 RUN GOOS=linux GOARCH=arm make cloudflared
-RUN mv cloudflared /cloudflared/cloudflared-armhf
+RUN mv cloudflared /root-layer/cloudflared/cloudflared-armhf
 
-# Runtime container
+COPY root/ /root-layer/
+
+## Single layer deployed image ##
 FROM scratch
-WORKDIR /
 
 LABEL maintainer="Spunkie"
 
-# copy cloudflared bins
-COPY --from=buildstage /cloudflared /cloudflared
-# copy local files
-COPY root/ /
+# Add files from buildstage
+COPY --from=buildstage /root-layer/ /