Create a script for compiling the jar

Author: ibbem

Dockerfile

@@ -23,11 +23,14 @@ RUN nix-build
 RUN mkdir -p /etc/fonts && nix-build nix/fontconfig.nix --out-link /etc/fonts/fonts.conf
 RUN mkdir -p /var/cache/fontconfig && nix-shell -p fontconfig --run fc-cache
 
+# We need `cp` to copy out the jar.
+RUN nix-build '<nixpkgs>' -A coreutils -o coreutils
+
 # Copy DiffDetective with all runtime dependencies (ignoring build-time
 # dependencies) to a separate folder. Such a subset of the Nix store is called a
 # closure and enables us to create a minimal Docker container.
 RUN mkdir closure
-RUN nix-store -qR result /etc/fonts/fonts.conf | xargs cp -Rt closure
+RUN nix-store -qR result /etc/fonts/fonts.conf coreutils | xargs cp -Rt closure
 
 # Start building the final container.
 FROM scratch
@@ -48,5 +51,8 @@ COPY data /home/user/data
 COPY --from=builder /etc/fonts/fonts.conf /etc/fonts/fonts.conf
 COPY --from=builder /var/cache/fontconfig /var/cache/fontconfig
 
+# Install `cp`
+COPY --from=builder /home/user/coreutils/bin/cp /bin/cp
+
 ENV DISPLAY=:0 HOME=/home/user
 CMD ["/DiffDetective/bin/DiffDetective-Demo"]

build-jar.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+
+cd "$(dirname "${BASH_SOURCE[0]}")" || exit
+
+if command -v nix-build &>/dev/null
+then
+  echo "Using Nix to build the DiffDetective demo jar."
+  nix-build &&
+  cp result/share/java/DiffDetective-Demo.jar . &&
+  echo "The jar has been built successfully. You can find it in $(realpath DiffDetective-Demo.jar)" &&
+  echo "You might want to remove the 'result' link ('rm result') to allow the Nix garbage collector to reclaim some space."
+elif command -v docker &>/dev/null
+then
+  echo "Using Docker to build the DiffDetective demo jar."
+
+  root=0
+  if ! groups | grep -q docker
+  then
+    if [ "$(id -u)" -ne 0 ]
+    then
+      echo >&2 "You don't seem to be able to run Docker as your user. Please start this script as root (e.g., using 'sudo') or ensure you are a member of the docker group."
+      exit 2
+    fi
+  fi
+
+  if ! docker version &>/dev/null
+  then
+    echo >&2 "Docker isn't running. You need to start the docker engine first."
+    echo >&2 "On most Linux distributions you can do so using 'systemctl start docker'."
+    exit 3
+  fi
+
+  docker build . --tag diffdetective-demo:1.0.0 &&
+  docker run --volume "$(realpath .):/output:rw" diffdetective-demo:1.0.0 /bin/cp /DiffDetective/share/java/DiffDetective-Demo.jar /output
+
+  if [ "$?" -eq 0 ]
+  then
+    echo
+    echo "The jar has been built successfully. You can find it in $(realpath DiffDetective-Demo.jar)"
+    echo "You might want to remove the Docker image ('docker image rm diffdetective-demo:1.0.0')."
+
+    if [ "$(id -u)" -eq 0 ]
+    then
+      echo "You might want to change the owner of the jar ('chown username:group DiffDetective-Demo.jar') because it's current owner is root."
+    fi
+  fi
+else
+  echo "Neither Nix nor Docker are installed. You need to compile the jar for yourselves. See INSTALL.md for instructions."
+fi