Update the docker multistage to copy only the necessary files (#9899)

* copy only the necessary files during stage 2 in multi-stage.

* update readme

examples/with-docker/Dockerfile.multistage

@@ -9,6 +9,8 @@ RUN yarn build && yarn --production
 # And then copy over node_modules, etc from that stage to the smaller base image
 FROM mhart/alpine-node:base
 WORKDIR /app
-COPY --from=builder /app .
+COPY --from=builder /app/node_modules ./node_modules
+COPY --from=builder /app/.next ./.next
+COPY --from=builder /app/next.config.js ./next.config.js
 EXPOSE 3000
 CMD ["node_modules/.bin/next", "start"]

examples/with-docker/README.md

@@ -30,7 +30,13 @@ docker build -t next-app .
 docker build -t next-app -f ./Dockerfile.multistage .
 ```
 
-Run it:
+Alternatively you can add these commands as scripts to your package.json and simply run
+
+`yarn build-docker`
+or
+`yarn build-docker-multistage`
+
+Run the docker image:
 
 ```bash
 docker run --rm -it \
@@ -39,6 +45,8 @@ docker run --rm -it \
   next-app
 ```
 
+or use `yarn build-docker-multistage`
+
 Deploy it to the cloud with [now](https://zeit.co/now) ([download](https://zeit.co/download))
 
 ```bash

examples/with-docker/package.json

@@ -4,7 +4,10 @@
   "scripts": {
     "dev": "next",
     "build": "next build",
-    "start": "next start"
+    "start": "next start",
+    "build-docker": "docker build -t next-app .",
+    "build-docker-multistage": "docker build -t next-app -f ./Dockerfile.multistage .",
+    "run-docker": "docker run --rm -it -p 3000:3000 -e 'API_URL=https://example.com' next-app"
   },
   "dependencies": {
     "next": "latest",