feature/846-async-logging (#84)

* Update docker config to handle logfile output

* Fix npm audit failure

Author: lewisdaly

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:10.15.3-alpine
+FROM node:10.15.3-alpine as builder
 USER root
 
 WORKDIR /opt/email-notifier
@@ -10,15 +10,23 @@ RUN apk add --no-cache -t build-dependencies make gcc g++ python libtool autocon
     && npm install -g node-gyp
 
 COPY package.json package-lock.json* /opt/email-notifier/
-RUN npm install --production && \
-  npm uninstall -g npm
-
-RUN apk del build-dependencies
+RUN npm install
 
 COPY src /opt/email-notifier/src
 COPY config /opt/email-notifier/config
 COPY app.js /opt/email-notifier/
 COPY templates /opt/email-notifier/templates
 
+FROM node:10.15.3-alpine
+
+WORKDIR /opt/email-notifier
+
+COPY --from=builder /opt/email-notifier .
+RUN npm prune --production
+
+# Create empty log file & link stdout to the application log file
+RUN mkdir ./logs && touch ./logs/combined.log
+RUN ln -sf /dev/stdout ./logs/combined.log
+
 EXPOSE 3081
 CMD node app.js