Speed up Docker build by sharing prod-deps and playwright-base stages

- Add prod-deps stage to run `npm ci --omit=dev` once (was twice)
- Add playwright-base stage to install Chromium once (was twice)
- Both app and scraper stages inherit from playwright-base
- Add BuildKit cache mounts for npm to accelerate repeated builds

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 20 insertions, 12 deletions

diff --git a/Dockerfile b/Dockerfile
index f5cfdb3..25c36dd 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,33 +1,41 @@
+# syntax=docker/dockerfile:1
+
 FROM node:20-alpine AS deps
-COPY package.json package-lock.json /app/
 WORKDIR /app
-RUN npm ci
+COPY package.json package-lock.json ./
+RUN --mount=type=cache,target=/root/.npm \
+    npm ci
 
 FROM node:20-alpine AS build
-COPY . /app/
-COPY --from=deps /app/node_modules /app/node_modules
 WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
 RUN npm run build
 
-FROM node:20-slim AS app
+FROM node:20-slim AS prod-deps
 WORKDIR /app
 COPY package.json package-lock.json ./
-RUN npm ci --omit=dev
-COPY --from=build /app/build ./build
+RUN --mount=type=cache,target=/root/.npm \
+    npm ci --omit=dev
+
+FROM node:20-slim AS playwright-base
+WORKDIR /app
+COPY package.json ./
+COPY --from=prod-deps /app/node_modules ./node_modules
 RUN npx playwright install chromium --with-deps
+
+FROM playwright-base AS app
+COPY --from=build /app/build ./build
 RUN mkdir -p /app/data
 EXPOSE 3000
 CMD ["npm", "start"]
 
-FROM node:20-slim AS scraper
-WORKDIR /app
-COPY package.json package-lock.json ./
-RUN npm ci --omit=dev && npm install tsx
+FROM playwright-base AS scraper
+RUN npm install tsx
 COPY --from=build /app/build ./build
 COPY scripts ./scripts
 COPY app ./app
 COPY tsconfig.json ./
-RUN npx playwright install chromium --with-deps
 RUN apt-get update && apt-get install -y cron && rm -rf /var/lib/apt/lists/*
 RUN echo '0 */6 * * * root cd /app && DB_PATH=/app/data/events.db node --import tsx/esm scripts/scrape.ts >> /app/data/scraper.log 2>&1' > /etc/cron.d/scraper \
     && chmod 0644 /etc/cron.d/scraper