Smaller Docker image (#622)

* Docker image has been greatly slimmed down and caches node_modules for rebuilds

* Update Dockerfile

* Dockerfile improvements

* Remove devDependencies from final image (#2)

* Remove devDependencies from final image

* Move to single-stage build

Dockerfile

@@ -1,24 +1,29 @@
-FROM node:7.8.0
+ARG NODE_IMAGE=node:10.1-alpine
 
-# Install runtime dependencies and remove state generated by apt-get before
-# creating intermediate image.
-RUN apt-get update && apt-get install -y mediainfo && rm -rf /var/lib/apt/lists/*
+FROM ${NODE_IMAGE} as nodebuild
 
-# Create app working directory.
-RUN mkdir -p /usr/src/app
 WORKDIR /usr/src/app
-COPY . /usr/src/app
 
-# Copy docker configuration file. This allows for specifying common configs with
-# just environment variables.
-COPY config.docker.js /usr/src/app/config.js
+# Generate node_modules
+COPY package.json ./package.json
+COPY package-lock.json ./package-lock.json
+RUN apk add --no-cache --virtual=build-dependencies \
+    python \
+    build-base && \
+    npm install && \
+    apk del --purge build-dependencies
 
-# Install Dependencies and remove cache to keep image small. This is done in one
-# step to keep the cache out of intermediate image.
-RUN npm install && npm cache clean --force
+# Build static assets and remove devDependencies.
+COPY client ./client
+COPY shared ./shared
+COPY config.docker.js ./config.js
+RUN npm run build && \
+    npm prune --production
+COPY server ./server
 
-# Build static assets.
-RUN npm run build
+# Install runtime dependencies.
+RUN apk --no-cache add \
+    mediainfo
 
 # Hints for consumers of the container.
 EXPOSE 3000