Create smaller docker images

Utilise multi-stage docker builds to reduce size from over 500MB to 100MB

* Base image uses minimal dependencies to run scripts in final stage e.g. only
using node in final CMD means we can move npm to compile stage.
* Reduced dbus-python build dependencies to those actually required.
* Using `pip install --user` to easily copy over Python requirements.
* Bumped Python base image version to 3.10
* Excluded unneeded files from final image.

.dockerignore

@@ -1 +1,7 @@
 node_modules
+.git
+.gitignore
+.github
+Dockerfile
+*.md
+LICENSE

Dockerfile

@@ -1,16 +1,40 @@
-FROM python:3.9.16-alpine3.17
+FROM python:3.10.10-alpine3.17 as base
 LABEL maintainer="Ben Hardill [email protected]"
+RUN apk add --no-cache --update \
+ dbus-libs \
+ 'nodejs<19'
 
-RUN \
- apk add --update autoconf automake make cmake pkgconfig gcc libc-dev g++ glib-dev linux-headers dbus dbus-dev && \
- apk add --update 'nodejs<19' 'npm<10' && \
- pip install -U pip && pip install pipenv && \
- rm -rf /var/lib/apt/lists/*
+# Install dependencies
+FROM base as compile-image
 
 WORKDIR /usr/src/app
 
-COPY . .
-RUN pip install mdns-publisher && \
- npm install
+RUN apk add --no-cache --update \
+ cmake \
+ g++ \
+ glib-dev \
+ dbus \
+ dbus-dev \
+ glib-dev \
+ 'npm<10' && \
+ pip install --upgrade --no-cache-dir pip
 
-CMD ["npm", "start"]
+RUN pip install --user --no-cache-dir mdns-publisher
+
+COPY package.json package-lock.json .
+RUN npm ci --production
+
+# Build application
+FROM base as build-image
+
+WORKDIR /usr/src/app
+
+# app
+COPY cname.py index.js .
+# npm packages
+COPY --from=compile-image /usr/src/app/node_modules node_modules
+# pip packages
+COPY --from=compile-image /root/.local /root/.local
+ENV PATH=/root/.local/bin:$PATH
+
+CMD ["node", "index.js"]