Dockerfile

# syntax=docker/dockerfile:1.7

# ---------------------------------------------------------------
# WatchDocs - Multi-stage production image
# Image:  watchdocs:1.0.0
# Port:   3355
# Output: Next.js standalone server
# ---------------------------------------------------------------

# ----- Stage 1: dependencies ---------------------------------------
FROM node:20-alpine AS deps
WORKDIR /app

# Enable corepack so pnpm is available without an extra install step
RUN corepack enable

# Copy only lockfiles to maximize Docker layer cache hits
COPY package.json pnpm-lock.yaml* package-lock.json* yarn.lock* ./

# Install dependencies using whichever lockfile is present
RUN \
  if [ -f pnpm-lock.yaml ]; then pnpm install --frozen-lockfile; \
  elif [ -f package-lock.json ]; then npm ci; \
  elif [ -f yarn.lock ]; then yarn install --frozen-lockfile; \
  else pnpm install; \
  fi


# ----- Stage 2: build ----------------------------------------------
FROM node:20-alpine AS builder
WORKDIR /app
RUN corepack enable

# Bring in installed modules and source
COPY --from=deps /app/node_modules ./node_modules
COPY . .

# Disable Next.js telemetry at build time
ENV NEXT_TELEMETRY_DISABLED=1

# Build the Next.js app (produces .next/standalone when output: 'standalone')
RUN \
  if [ -f pnpm-lock.yaml ]; then pnpm build; \
  elif [ -f package-lock.json ]; then npm run build; \
  elif [ -f yarn.lock ]; then yarn build; \
  else pnpm build; \
  fi


# ----- Stage 3: runner (slim production image) --------------------
FROM node:20-alpine AS runner
WORKDIR /app

# Production defaults
ENV NODE_ENV=production
ENV NEXT_TELEMETRY_DISABLED=1
ENV PORT=3355
ENV HOSTNAME=0.0.0.0

# Create a non-root user so the app does not run as root
RUN addgroup --system --gid 1001 nodejs \
 && adduser  --system --uid 1001 nextjs

# Copy the public directory (static assets served directly)
COPY --from=builder /app/public ./public

# Copy the standalone server and its required static chunks
# Ownership is assigned to the nextjs user for tighter permissions
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static

USER nextjs

EXPOSE 3355

# Lightweight healthcheck - Next.js standalone answers on the root path
HEALTHCHECK --interval=30s --timeout=5s --start-period=20s --retries=3 \
  CMD wget --no-verbose --tries=1 --spider http://127.0.0.1:3355/ || exit 1

# server.js is generated by Next.js standalone output
CMD ["node", "server.js"]