Rework auth Dockerfile so it builds on M1

src/api/sso/Dockerfile

@@ -1,12 +1,50 @@
-FROM node:lts-alpine as base
-RUN apk add dumb-init
-WORKDIR /app
-COPY --chown=node:node ./package.json ./
+## Base ########################################################################
+# Use a larger node image to do the build for native deps (e.g., gcc, pytyhon)
+FROM node:lts as base
 
-FROM base AS dependencies
-RUN npm install --only=production --no-package-lock
+# Reduce npm log spam and colour during install within Docker
+ENV NPM_CONFIG_LOGLEVEL=warn
+ENV NPM_CONFIG_COLOR=false
 
-FROM dependencies as deploy
-COPY --chown=node:node ./src ./src
+# We'll run the app as the `node` user, so put it in their home directory
+WORKDIR /home/node/app
+# Copy the package.json and lock file over
+COPY package*.json /home/node/app/
+
+## Development #################################################################
+# Define a development target that installs devDeps and runs in dev mode
+FROM base as development
+WORKDIR /home/node/app
+# Install (not ci) with dependencies, and for Linux vs. Linux Musl (which we use for -alpine)
+RUN npm install
+# Copy the source code over
+COPY --chown=node:node . /home/node/app/
+# Switch to the node user vs. root
+USER node
+# Start the app in debug mode so we can attach the debugger
+CMD ["npm", "run", "dev"]
+
+## Production ##################################################################
+# Also define a production target which doesn't use devDeps
+FROM base as production
+WORKDIR /home/node/app
+# We'll install production only deps, and target the Linux Musl x64 for alpine.
+RUN npm install --platform=linuxmusl --arch=x64 --production
+
+## Deploy ######################################################################
+# Use a smaller node image (-alpine) at runtime
+FROM node:lts-alpine as deploy
+# Install dumb-init, see:
+# https://snyk.io/blog/10-best-practices-to-containerize-nodejs-web-applications-with-docker/
+# Install specific version, and don't cache https://github.com/hadolint/hadolint/wiki/DL3018
+# https://pkgs.alpinelinux.org/package/edge/community/x86/dumb-init
+RUN apk --no-cache add dumb-init=1.2.5-r1
+WORKDIR /home/node/app
+# Copy what we've installed/built from production
+COPY --chown=node:node --from=production /home/node/app/node_modules /home/node/app/node_modules/
+# Copy the source code
+COPY --chown=node:node . /home/node/app/
+# Switch to the node user vs. root
 USER node
+# Start the app
 CMD ["dumb-init", "node", "src/server.js"]