Shrink the docker image via multi-stage builds

This restructures the entire docker image build process to first
install bw_plex and its python dependencies into a virtualenv in a
"builder" docker container; then the main image build merely installs
the runtime dependencies and copies the virtualenv contents over,
setting the appropriate $PATH variable.

Additionally, use the contents of the current git checkout to build
the docker image, as opposed to downloading the source code from
github & pip-installing that. In addition to saving space, should
allow developers to test their changes better.

.dockerignore

@@ -0,0 +1,7 @@
+__pycache__
+*.pyc
+*.pyo
+*.pyd
+.Python
+*.whl
+Dockerfile

Dockerfile

@@ -1,8 +1,24 @@
+FROM ubuntu:18.04 AS builder
+ENV DEBIAN_FRONTEND="noninteractive"
+ENV LC_ALL C.UTF-8
+ENV lang C.UTF-8
+RUN apt-get update && apt-get -y install \
+  git-core swig libpulse-dev libasound2-dev ffmpeg tesseract-ocr python3-pip pandoc python3.6-tk \
+  python3-setuptools python3-venv && apt-get clean \
+  && rm -rf /var/lib/apt/lists/* && \
+  python3 -m venv /app/bw_plex
+
+ENV PATH="/app/bw_plex/bin:$PATH"
+WORKDIR /src
+
+# Python requirements from pip
+RUN pip3 --no-cache-dir install pytest pytest-cov pytest-mock pytest_click pypandoc codecov \
+  opencv-contrib-python-headless SpeechRecognition pocketsphinx pytesseract
+
+ADD . /src
+RUN pip3 --no-cache-dir wheel -e . && pip3 --no-cache-dir install bw_plex*.whl
+
 FROM ubuntu:18.04
-
-# This images is much bigger then i want, ill try to reduce it
-# but im such a docker noob, send a PR if you know how to fix it.
-
 LABEL maintainer="hellowlol1@gmail.com"
 
 ENV DEBIAN_FRONTEND="noninteractive"
@@ -11,22 +27,12 @@ ENV lang C.UTF-8
 
 # Package requirements
 RUN apt-get update && apt-get -y install \
-  git swig libpulse-dev libasound2-dev ffmpeg tesseract-ocr python3-pip pandoc python3.6-tk \
-  python3-setuptools && apt-get clean \
-  && rm -rf /var/lib/apt/lists/* && \
-  mkdir -p /app/bw_plex
+  libpulse0 libasound2 ffmpeg tesseract-ocr python3-pip pandoc python3.6-tk \
+  && apt-get clean \
+  && rm -rf /var/lib/apt/lists/*
 
-# Python requirements from pip
-RUN pip3 install pytest pytest-cov pytest-mock pytest_click pypandoc codecov \
-  opencv-contrib-python-headless SpeechRecognition pocketsphinx pytesseract
-
-RUN git clone --depth=1 https://github.com/Hellowlol/bw_plex.git /app/bw_plex
-#&& rm -rf /app/bw_plex/.git
-
-# This is needed for the the manual install of bw_plex
-WORKDIR /app/bw_plex
-
-RUN pip3 install -e .
+COPY --from=builder /app/bw_plex /app/bw_plex
+ENV PATH="/app/bw_plex/bin:$PATH"
 
 # COPY root/ /
 VOLUME /config