docker-compose：未能解决：rpc 错误：代码 = Unknown desc = 无法计算缓存键答案

【问题标题】：docker-compose: failed to solve: rpc error: code = Unknown desc = failed to compute cache keydocker-compose：未能解决：rpc 错误：代码 = Unknown desc = 无法计算缓存键
【发布时间】：2021-09-30 09:26:28
【问题描述】：

当我使用docker build 和docker run 运行我的dockerfile 时，它运行良好。但是当我创建一个docker-compose.yml 文件来连接 mongoDB 时，我得到了一个错误。

错误：failed to solve: rpc error: code = Unknown desc = failed to compute cache key: failed to walk /var/lib/docker/tmp/buildkit-mount285447202/backend: lstat /var/lib/docker/tmp/buildkit-mount285447202/backend: no such file or directory。

这是我的 docker-compose 代码：

version: "3"
services:   
  backend: 
    build: 
      context: ./docker
      dockerfile: Dockerfile.backend
    container_name: backend
    ports: 
      - '8081:8081'
    links:  
      - mongodb
  mongodb:
    container_name: mongodb
    image: mongo
    ports:
      - '27017:27017'

这是我的 dockerfile 代码：

FROM node:14-alpine AS builder
WORKDIR /app
COPY backend/package.json backend/package-lock.json ./
RUN npm install

COPY backend/src/ ./src
COPY backend/.env ./
COPY backend/.babelrc ./
RUN mkdir -p build/src
RUN npm run build

FROM node:alpine AS runner
WORKDIR /app

RUN apk add --no-cache \
      chromium \
      nss \
      freetype \
      harfbuzz \
      ca-certificates \
      ttf-freefont

ENV PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true \
    PUPPETEER_EXECUTABLE_PATH=/usr/bin/chromium-browser

RUN npm install puppeteer@10.0.0

RUN addgroup -S pptruser && adduser -S -g pptruser pptruser \
    && mkdir -p /home/pptruser/Downloads /app \
    && chown -R pptruser:pptruser /home/pptruser \
    && chown -R pptruser:pptruser /app

# USER pptruser
USER root

COPY --from=builder /app/package.json ./
COPY --from=builder /app/package-lock.json ./
COPY --from=builder /app/.env ./
COPY --from=builder /app/build ./build
COPY --from=builder /app/node_modules ./node_modules

EXPOSE 8081

CMD ["node", "build/src/index.js"]

我在以下位置遇到错误：

=> ERROR [builder 3/9] COPY backend/package.json backend/package-lock.json ./                                   0.0s 
 => CACHED [builder 4/9] RUN npm install                                                                         0.0s 
 => ERROR [builder 5/9] COPY backend/src/ ./src                                                                  0.0s 
 => ERROR [builder 6/9] COPY backend/.env ./                                                                     0.0s 
 => ERROR [builder 7/9] COPY backend/.babelrc ./                                                                 0.0s

我的目录：

|-docker-compose.yml
|-backend
| |-src
| |-package.json
| |-package-lock.json 
| |-build
| |-...
|-docker
| |-Dockerfile.backend
| |-Dockerfile.frontend
|....

【问题讨论】：

标签： node.js docker docker-compose

【解决方案1】：

这通常发生在Dockerfile 找不到文件夹时，例如

Dockerfile：

FROM alpine:3.8
COPY backend /tmp

执行：

$ docker build .
Sending build context to Docker daemon  2.048kB
Step 1/2 : FROM alpine:3.8
 ---> c8bccc0af957
Step 2/2 : COPY backend /tmp
COPY failed: stat /var/lib/docker/tmp/docker-builder736780062/backend: no such file or directory

确保context 文件夹（这里是docker）拥有backend 文件夹。

对你来说，正确的做法应该是：

version: "3"
services:
  backend:
    build:
      context: .
      dockerfile: docker/Dockerfile.backend

【讨论】：