COPY failed: stat app/build: file does not exist

Docker fullstack app

github -> travis ci -> docker hub -> aws

강의에서 travis ci에서

5.28s$ docker build -t [secure]/docker-frontend ./frontend

진행시 오류가 납니다.

Step 10/10 : COPY --from=builder /app/build /usr/share/nginx/html

320COPY failed: stat app/build: file does not exist

Dockerfile 내용

FROM node:alpine as builder

WORKDIR /app

COPY ./package.json ./

RUN npm install

COPY ./ ./

CMD npm run build

FROM nginx
EXPOSE 3000
COPY ./nginx/default.conf /etc/nginx/conf.d/default.conf
COPY --from=builder /app/build /usr/share/nginx/html