update dockerfile

Dockerfile

@@ -1,23 +1,38 @@
 # https://dev.to/code42cate/how-to-dockerize-and-deploy-astro-6ll
 
-FROM node:alpine AS base
+# use the official Bun image
+# see all versions at https://hub.docker.com/r/oven/bun/tags
+FROM oven/bun:1-alpine AS base
 WORKDIR /app
 
-COPY package.json package-lock.json ./
+# install dependencies into temp directory
+# this will cache them and speed up future builds
+FROM base AS install
+RUN mkdir -p /temp/dev
+COPY package.json bun.lock /temp/dev/
+RUN cd /temp/dev && bun install --frozen-lockfile
 
-FROM base AS deps
-RUN npm install
+# install with --production (exclude devDependencies)
+RUN mkdir -p /temp/prod
+COPY package.json bun.lock /temp/prod/
+RUN cd /temp/prod && bun install --frozen-lockfile --production
 
-FROM deps AS build
+# copy node_modules from temp directory
+# then copy all (non-ignored) project files into the image
+FROM base AS prerelease
+COPY --from=install /temp/dev/node_modules node_modules
 COPY . .
-RUN npm run build
 
-FROM base AS runtime
-COPY --from=deps /app/node_modules ./node_modules
-COPY --from=build /app/dist ./dist
+# build
+RUN bun run build
 
-ENV HOST=0.0.0.0
-ENV PORT=3000
-EXPOSE 3000
+# copy production dependencies and source code into final image
+FROM base AS release
+COPY --from=install /temp/prod/node_modules node_modules
+COPY --from=prerelease /app/index.ts .
+COPY --from=prerelease /app/package.json .
 
-CMD node ./dist/server/entry.mjs
+# run the app
+USER bun
+EXPOSE 3000
+CMD bun run ./dist/server/entry.mjs