Refactor, run as root instead

Dockerfile

@@ -2,12 +2,12 @@
 
 FROM ubuntu:16.04
 
-# Never ask for confirmations
-ENV DEBIAN_FRONTEND noninteractive
-
 # SDK version
 ENV ANDROID_SDK_VERSION 3859397
 
+# Never ask for confirmations
+ENV DEBIAN_FRONTEND noninteractive
+
 # Update apt-get
 RUN apt-get -qq update \
   && apt-get -qq install -y --no-install-recommends \
@@ -29,15 +29,15 @@ RUN wget https://dl.google.com/android/repository/sdk-tools-linux-$ANDROID_SDK_V
   && unzip -q sdk-tools-linux-$ANDROID_SDK_VERSION.zip -d /usr/local/android \
   && rm sdk-tools-linux-$ANDROID_SDK_VERSION.zip
 
+# Export JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-8-openjdk-amd64
+
 # Environment variables
 ENV ANDROID_HOME /usr/local/android
 ENV ANDROID_SDK_HOME $ANDROID_HOME
 ENV ANDROID_NDK_HOME $ANDROID_HOME/ndk-bundle
 ENV PATH $ANDROID_HOME/tools/bin:$PATH
 
-# Export JAVA_HOME variable
-ENV JAVA_HOME /usr/lib/jvm/java-8-openjdk-amd64
-
 # Install Android SDK components
 RUN echo "y" | sdkmanager \
 #  "ndk-bundle" \
@@ -47,34 +47,11 @@ RUN echo "y" | sdkmanager \
   "platforms;android-26" \
   "build-tools;26.0.2"
 
+# Build directory
+ENV SRC /src
+RUN mkdir $SRC
+WORKDIR $SRC
 
-# Support Gradle
-ENV TERM dumb
-ENV JAVA_OPTS "-Xms512m -Xmx1024m"
-ENV GRADLE_OPTS "-XX:+UseG1GC -XX:MaxGCPauseMillis=1000"
-
-# Add build user account, values are set to default below
-ENV RUN_USER builder
-ENV RUN_UID 5000
-
-RUN id $RUN_USER || adduser --uid "$RUN_UID" \
-  --gecos 'Build User' \
-  --shell '/bin/sh' \
-  --disabled-login \
-  --disabled-password "$RUN_USER"
-
-# Fix permissions
-RUN chown -R $RUN_USER:$RUN_USER $ANDROID_HOME
-RUN chmod -R a+rx $ANDROID_HOME
-
-# Creating project directories prepared for build when running
-# `docker run`
-ENV PROJECT /project
-RUN mkdir $PROJECT
-RUN chown -R $RUN_USER:$RUN_USER $PROJECT
-WORKDIR $PROJECT
-
-USER $RUN_USER
 RUN echo "sdk.dir=$ANDROID_HOME" > local.properties
 
 CMD ["./gradlew", "build"]