Adjust docker build to use current user ID (#977)

build/docker/alpine.Dockerfile

@@ -1,5 +1,11 @@
 FROM microsoft/dotnet:2.1-runtime-deps-alpine
+ARG USER
+ARG USER_ID
+ARG GROUP_ID
+
 WORKDIR /code/build
+RUN mkdir -p "/home/$USER" && chown "${USER_ID}:${GROUP_ID}" "/home/$USER"
+ENV HOME "/home/$USER"
 
 RUN apk add --no-cache \
         bash \
@@ -10,6 +16,8 @@ RUN apk add --no-cache \
         icu-libs \
         openssl
 
+USER $USER_ID:$GROUP_ID
+
 # Disable the invariant mode (set in base image)
 ENV DOTNET_SYSTEM_GLOBALIZATION_INVARIANT false
 ENV LC_ALL en_US.UTF-8
@@ -26,6 +34,5 @@ COPY global.json /tmp/global.json
 RUN DOTNET_SDK_VERSION="$(jq -r '.sdk.version' /tmp/global.json)" \
     && echo "Installing SDK ${DOTNET_SDK_VERSION}" \
     && wget -q --tries 10 -O /tmp/dotnet.tar.gz https://dotnetcli.blob.core.windows.net/dotnet/Sdk/$DOTNET_SDK_VERSION/dotnet-sdk-$DOTNET_SDK_VERSION-alpine.3.6-x64.tar.gz \
-    && mkdir -p /usr/share/dotnet \
+    && mkdir -p "$HOME/.dotnet" \
-    && tar xzf /tmp/dotnet.tar.gz -C /usr/share/dotnet \
+    && tar xzf /tmp/dotnet.tar.gz -C "$HOME/.dotnet"
-    && ln -s /usr/share/dotnet/dotnet /usr/bin/dotnet

dockerbuild.sh

@@ -97,7 +97,12 @@ tagname="universe-build-$image"
 cp "$DIR/global.json" "$(dirname "$dockerfile")"
 #endworkaround
 
-docker build "$(dirname "$dockerfile")" -f "$dockerfile" --tag $tagname
+docker build "$(dirname "$dockerfile")" \
+    --build-arg "USER=$(whoami)" \
+    --build-arg "USER_ID=$(id -u)" \
+    --build-arg "GROUP_ID=$(id -g)" \
+    --tag $tagname \
+    -f "$dockerfile"
 
 docker run \
     --rm \