Docker

In many cases, we build our application with Docker to enable easy hosting on external servers.

One of the most efficient ways to do this is using a technique called Multi-stage builds, which consists of multiple stages that prepare the application and produce a final image containing only the production code. Here’s an example:

# Phase 1: Build the application
FROM node:22-alpine AS builder
WORKDIR /app

COPY package.json package-lock.json ./
RUN npm ci

COPY . .
RUN npm run build

# Phase 2: Prepare the production image
FROM node:22-alpine AS production
WORKDIR /app

ENV NODE_ENV=production

COPY package.json package-lock.json ./
RUN npm ci --include=prod

## Output from build step on builder stage
COPY --from=builder /app/dist ./dist
## Production server
COPY server.js ./

EXPOSE 5173

CMD ["node", "server.js"]

This strategy produces a much leaner image that includes only production dependencies and the bundled files.

If you are already using this approach and add layerfig, you may encounter an error like this:

Error: File "/app/config/base.json" does not exist
    at ConfigBuilder.addSource (file:///app/node_modules/@layerfig/config/dist/index.js:78:46)
    at file:///app/dist/server/entry-server.js:6:48
    at ModuleJob.run (node:internal/modules/esm/module_job:274:25)
    at async onImport.tracePromise.__proto__ (node:internal/modules/esm/loader:644:26)
    at async file:///app/server.js:51:17

This error occurs because you need to include the configuration files in the final production stage:

# Phase 1: Build the application
FROM node:22-alpine AS builder
WORKDIR /app

COPY package.json package-lock.json ./
RUN npm ci

COPY . .
RUN npm run build

# Phase 2: Prepare the production image
FROM node:22-alpine AS production
WORKDIR /app

ENV NODE_ENV=production

COPY package.json package-lock.json ./
RUN npm ci --include=prod

## Output from build step on builder stage
COPY --from=builder /app/dist ./dist
## Production server
COPY server.js .

## Include configuration files
COPY ./config ./config

EXPOSE 5173

CMD ["node", "server.js"]

Now your application will include the configuration files and load them correctly.