Dockerfile

###################
# BUILD FOR LOCAL DEVELOPMENT
###################
# In this step we copy over everything we need and install all dependancies
# We stop at the end of this step in development, so it also includes the deploy command
# We install jest, eslint and ts-node so we can run tests and lint.

FROM node:20.5.0-alpine AS development

ENV TZ="America/Chicago"
ENV NODE_ENV=development
RUN date

# Create app directory
WORKDIR /usr/src/app

# Copy application dependency manifests to the container image.
# A wildcard is used to ensure copying both package.json AND package-lock.json (when available).
# Copying this first prevents re-running npm install on every code change.
COPY --chown=node:node package*.json ./

# Install app dependencies using the `npm ci` command instead of `npm install`
# Use NPM CI even though this may be your first time, cuz package-lock already thinks you installed stuff
RUN npm ci

# Bundle app source
COPY --chown=node:node . .

# Use the node user from the image (instead of the root user)
# USER node

# For container development, the following command runs forever, so we can inspect the container
CMD npx tsc-watch --onSuccess "npx nodemon --config ./nodemon.json"

###################
# BUILD FOR PRODUCTION
###################
# This stage prepares for and builds the production .js code
# We copy over the node_modules directory from the development image to ensure that the production image has access to all the dependencies it needs
# Then we copy over everything else that may be needed to run
# We run the build command which creates the production bundle
# We run npm ci --only=production to ensure that only the production dependencies are installed

FROM node:20.5.0-alpine AS build

ENV TZ="America/Chicago"
ENV NODE_ENV=production
RUN date

# Create app directory
WORKDIR /usr/src/app

# Run the build command which creates the production bundle
# This comes before the next command cuz ts is a dev requirement and we don't want it in the production image
RUN npm install -g --save-dev typescript

# In order to run `npm run build` we need access to the Nest CLI which is a dev dependency. In the previous development stage we ran `npm ci` which installed all dependencies, so we can copy over the node_modules directory from the development image
COPY --chown=node:node --from=development /usr/src/app/node_modules ./node_modules

# Copy over the existing source code
COPY --chown=node:node . .

# Running `npm ci` removes the existing node_modules directory and passing in --only=production ensures that only the production dependencies are installed. This ensures that the node_modules directory is as optimized as possible
RUN npm ci --omit:dev && npm cache clean --force

###################
# PRODUCTION
###################
# This stage creates the final, small-as-can-be, production image
# We copy over the node_modules directory from the build stage
# Then we ONLY copy over the /build folder with the js files
# We already deployed before, so the only thing left to do is run the bot with PM2

FROM node:20.5.0-alpine AS production

ENV TZ="America/Chicago"
ENV NODE_ENV=production
RUN date

# Create app directory
WORKDIR /usr/src/app

# Install pm2
RUN npm install pm2 -g

# # Copy the bundled code from the build stage to the production image
COPY --chown=node:node --from=build /usr/src/app/node_modules ./node_modules
COPY --chown=node:node --from=build /usr/src/app/build ./build

USER node

# Start the bot using the production build
CMD ["pm2-runtime", "build/start.js"]