Add Dockerfile

- Add ability to run pretty-format-java inside this docker container

.pre-commit-hooks.yaml

@@ -16,7 +16,7 @@
   name: Google Java Formatter
   description: Runs Google Java Formatter over Java source files
   entry: pretty-format-java
-  language: python
+  language: docker
   types: [java]
   # this is needed because the hook downloads google-java-formatter and
   # we don't have yet a nice way of ensuring a single download over multiple runs

Dockerfile

@@ -0,0 +1,24 @@
+FROM ubuntu:18.04
+
+# Make sure dependencies are installed
+RUN apt-get update && apt-get install -y python3 python3-pip
+RUN apt-get install -y python3-setuptools
+RUN apt install -y default-jre
+RUN pip3 install setuptools --upgrade
+
+# Put the source files in the build container
+COPY . /src/
+
+# Set working directory to where we want to run install commands from
+WORKDIR /src
+
+# Install formattters to container
+RUN python3 /src/setup.py install
+
+# Configure environment variables into writeable directory
+RUN mkdir -p /src/cache/.python-eggs
+RUN chmod 777 /src/cache
+ENV PYTHON_EGG_CACHE=/src/cache/.python-eggs
+ENV PRE_COMMIT_HOME /src/cache
+
+ENTRYPOINT /bin/bash