Minor cleanup to production Dockerfile. Update to Node v22. Add inline comments. Use Dockerfile best practices for ENTRYPOINT vs CMD. Switch to "npm ci" which is recommended for Docker environments.

Author: tdonohue

Dockerfile.dist

@@ -4,28 +4,46 @@
 # Test build:
 # docker build -f Dockerfile.dist -t dspace/dspace-angular:latest-dist .
 
-FROM docker.io/node:20-alpine AS build
+# Step 1 - Build code for production
+FROM docker.io/node:22-alpine AS build
 
 # Ensure Python and other build tools are available
 # These are needed to install some node modules, especially on linux/arm64
 RUN apk add --update python3 make g++ && rm -rf /var/cache/apk/*
 
 WORKDIR /app
+# Copy over package files first, so this layer will only be rebuilt if those files change.
 COPY package.json package-lock.json ./
-RUN npm install
+# NOTE: "ci" = clean install from package files
+RUN npm ci
 
-ADD . /app/
+# Around 4GB of memory is required to build the app for production.
+# This default setting can be overridden as needed in your shell, via an env file or in docker-compose.
+# See Docker environment var precedence: https://docs.docker.com/compose/environment-variables/envvars-precedence/
+ENV NODE_OPTIONS="--max_old_space_size=4096"
+
+COPY . /app/
 RUN npm run build:prod
 
-FROM node:20-alpine
+# Step 2 - Start up UI via PM2
+FROM docker.io/node:22-alpine
+
+# Install PM2
 RUN npm install --global pm2
 
+# Copy pre-built code from build image
 COPY --chown=node:node --from=build /app/dist /app/dist
+# Copy configs and PM2 startup script from local machine
 COPY --chown=node:node config /app/config
 COPY --chown=node:node docker/dspace-ui.json /app/dspace-ui.json
 
+# Start up UI in PM2 in production mode
 WORKDIR /app
 USER node
 ENV NODE_ENV=production
 EXPOSE 4000
-CMD pm2-runtime start dspace-ui.json --json
+
+# On startup, run start the DSpace UI in PM2
+ENTRYPOINT [ "pm2-runtime", "start", "dspace-ui.json" ]
+# By default, pass param that specifies to use JSON format logs.
+CMD ["--json"]