GitHub CI部署Next.js时Docker无法找到.env.production文件

使用Docker和GitHub CI部署Next.js应用时，GitHub Actions流程执行正常，但Dockerfile引用.env.production文件时提示找不到。已尝试重命名文件、修改路径、更换SpicyPizza/create-envfile版本，且该文件未被.dockerignore或.gitignore忽略。

错误信息：

ERROR: failed to solve: process "/bin/sh -c cat .env.production && yarn global add pnpm && SKIP_ENV_VALIDATION=1 pnpm run build" did not complete successfully: exit code: 1
Error: buildx failed with: ERROR: failed to solve: process "/bin/sh -c cat .env.production && yarn global add pnpm && SKIP_ENV_VALIDATION=1 pnpm run build" did not complete successfully: exit code: 1

当前GitHub CI配置：

name: Docker Image CI
on:
  push:
    branches: [ "main" ]
jobs:
  build:
    environment: production
    runs-on: ubuntu-latest
    steps:
      - name: Check out the repository
        uses: actions/checkout@v3

      - name: Login to Docker Hub
        uses: docker/login-action@v2
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Create .env file
        uses: SpicyPizza/create-envfile@v2
        with:
          envkey_EMAIL_SERVER: ${{vars.EMAIL_SERVER}}
          envkey_EMAIL_FROM: ${{vars.EMAIL_FROM}}
          envkey_EMAIL_TO: ${{vars.EMAIL_TO}}
          envkey_NEXT_PUBLIC_RECAPTCHA_SITE_KEY: ${{vars.NEXT_PUBLIC_RECAPTCHA_SITE_KEY}}
          envkey_RECAPTCHA_SECRET_KEY: ${{secrets.RECAPTCHA_SECRET_KEY}}
          file_name: .env.production

      - name: Build and push Docker image
        uses: docker/build-push-action@v4
        with:
          push: true
          tags: ${{ secrets.DOCKERHUB_REPO }}:latest

Dockerfile内容：

##### DEPENDENCIES
FROM node:20-alpine AS deps
RUN apk add --no-cache libc6-compat openssl1.1-compat
WORKDIR /app

# Install dependencies
COPY package.json pnpm-lock.yaml* ./
RUN yarn global add pnpm && pnpm i

##### BUILDER
FROM node:20-alpine AS builder
WORKDIR /app
COPY . .
COPY --from=deps /app/node_modules ./node_modules

ENV NODE_ENV=production
ENV NEXT_TELEMETRY_DISABLED 1

RUN cat .env.production && yarn global add pnpm && SKIP_ENV_VALIDATION=1 pnpm run build

##### RUNNER
FROM node:20-alpine AS runner
WORKDIR /app

ENV NODE_ENV production
ENV NEXT_TELEMETRY_DISABLED 1

USER root
RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 nextjs

COPY --from=builder /app/next.config.mjs ./
COPY --from=builder /app/public ./public
COPY --from=builder /app/package.json ./package.json

COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static

COPY --from=builder --chown=nextjs:nodejs .env.production ./


USER nextjs
EXPOSE 3000
ENV PORT 3000

CMD ["node", "server.js"]

核心问题是**.env.production被.dockerignore规则排除，导致无法复制到Docker构建的builder阶段**。默认的Next.js项目.dockerignore通常会包含.env*这类本地环境文件，即使手动生成该文件，也会被忽略，最终导致cat .env.production执行失败。

以下是三种可行的修复方案，任选其一即可：

方案1：修改.dockerignore允许复制.env.production #

在项目根目录的.dockerignore文件中添加一行，取消对.env.production的忽略：

!.env.production

如果你的.dockerignore中已有.env*或.env.production的忽略规则，这行代码会覆盖原有规则，确保该文件能被复制到构建上下文。

方案2：在Dockerfile中单独复制.env.production #

先按方案1修改.dockerignore，然后在Dockerfile的builder阶段，将COPY . .替换为更精准的文件复制，同时单独指定.env.production：

##### BUILDER
FROM node:20-alpine AS builder
WORKDIR /app
# 复制项目核心文件
COPY package.json pnpm-lock.yaml* ./
COPY next.config.mjs ./
COPY src/ ./src/
COPY public/ ./public/
# 单独复制.env.production
COPY .env.production ./
COPY --from=deps /app/node_modules ./node_modules

ENV NODE_ENV=production
ENV NEXT_TELEMETRY_DISABLED 1

RUN yarn global add pnpm && SKIP_ENV_VALIDATION=1 pnpm run build

这种方式避免了复制不必要的文件，也确保.env.production被正确复制到镜像中。

方案3：通过构建参数传递环境变量（推荐） #

不需要生成.env.production文件，直接在GitHub CI中通过构建参数传递环境变量，完全规避.dockerignore的问题：

修改GitHub CI配置 #

在Build and push Docker image步骤中添加build-args：

- name: Build and push Docker image
  uses: docker/build-push-action@v4
  with:
    push: true
    tags: ${{ secrets.DOCKERHUB_REPO }}:latest
    build-args: |
      EMAIL_SERVER=${{vars.EMAIL_SERVER}}
      EMAIL_FROM=${{vars.EMAIL_FROM}}
      EMAIL_TO=${{vars.EMAIL_TO}}
      NEXT_PUBLIC_RECAPTCHA_SITE_KEY=${{vars.NEXT_PUBLIC_RECAPTCHA_SITE_KEY}}
      RECAPTCHA_SECRET_KEY=${{secrets.RECAPTCHA_SECRET_KEY}}

修改Dockerfile的builder阶段 #

添加构建参数声明并设置为环境变量：

##### BUILDER
FROM node:20-alpine AS builder
WORKDIR /app
COPY . .
COPY --from=deps /app/node_modules ./node_modules

# 声明构建参数
ARG EMAIL_SERVER
ARG EMAIL_FROM
ARG EMAIL_TO
ARG NEXT_PUBLIC_RECAPTCHA_SITE_KEY
ARG RECAPTCHA_SECRET_KEY

# 将构建参数转为环境变量
ENV NODE_ENV=production
ENV NEXT_TELEMETRY_DISABLED 1
ENV EMAIL_SERVER=$EMAIL_SERVER
ENV EMAIL_FROM=$EMAIL_FROM
ENV EMAIL_TO=$EMAIL_TO
ENV NEXT_PUBLIC_RECAPTCHA_SITE_KEY=$NEXT_PUBLIC_RECAPTCHA_SITE_KEY
ENV RECAPTCHA_SECRET_KEY=$RECAPTCHA_SECRET_KEY

RUN yarn global add pnpm && SKIP_ENV_VALIDATION=1 pnpm run build

这种方式更安全，环境变量不会以文件形式出现在镜像中，也避免了.dockerignore的干扰。

内容的提问来源于stack exchange，提问作者user16976770