# ❌ 低效：先复制所有代码，再安装依赖
FROM node:18
WORKDIR /app
COPY . .
RUN npm ci      # 代码变了就要重新安装

# ✅ 高效：先复制依赖文件，安装依赖，再复制代码
FROM node:18
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci            # 只有依赖文件变化才重装
COPY . .
RUN npm run build

# ❌ 多个 RUN 指令，每层都有缓存
RUN apt-get update
RUN apt-get install -y curl
RUN apt-get install -y vim

# ✅ 合并为一个 RUN 层
RUN apt-get update && \
    apt-get install -y curl vim && \
    rm -rf /var/lib/apt/lists/*

# .dockerignore - 减少上下文大小
node_modules
.git
*.log
.env
dist
.cache
.DS_Store

# syntax=docker/dockerfile:1
FROM golang:1.21

# Go 模块缓存
RUN --mount=type=cache,target=/go/pkg/mod \
    go mod download

# Go 构建缓存
RUN --mount=type=cache,target=/root/.cache/go-build \
    go build -o /app/server

FROM node:18

# npm 缓存
RUN --mount=type=cache,target=/root/.npm \
    npm ci

# 如果使用 pnpm
RUN --mount=type=cache,target=/root/.local/share/pnpm/store \
    pnpm install

# 只读挂载构建时的依赖
RUN --mount=type=bind,source=package.json,target=package.json \
    --mount=type=bind,source=package-lock.json,target=package-lock.json \
    npm ci

- name: Build with cache
  uses: docker/build-push-action@v5
  with:
    push: true
    cache-from: type=gha
    cache-to: type=gha,mode=max

build:
  script:
    - docker buildx build
        --cache-from type=registry,ref=$CI_REGISTRY_IMAGE:cache
        --cache-to type=registry,ref=$CI_REGISTRY_IMAGE:cache,mode=max
        -t $CI_REGISTRY_IMAGE:$CI_COMMIT_SHORT_SHA
        --push .

# 使用 registry 缓存
docker build \
  --cache-from registry.example.com/myapp:cache \
  --build-arg BUILDKIT_INLINE_CACHE=1 \
  -t myapp:latest .

# 推送缓存
docker push myapp:cache

# 合理拆分阶段，最大化缓存利用
FROM node:18 AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci

FROM node:18 AS build
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
RUN npm run build

FROM nginx:alpine AS production
COPY --from=build /app/dist /usr/share/nginx/html

# 检查缓存使用情况
DOCKER_BUILDKIT=1 docker build --progress=plain -t myapp . 2>&1 | grep "CACHED"

# 检查镜像层
docker history myapp:latest

# 分析哪层缓存未命中
docker build --no-cache-filter=build -t myapp .

# 只有 package.json 变化时重建依赖层
COPY package.json yarn.lock ./
RUN --mount=type=cache,target=/usr/local/share/.cache/yarn \
    yarn install --frozen-lockfile

# 利用 BuildKit 的 --mount 实现更精细的缓存
RUN --mount=type=cache,target=/app/node_modules \
    --mount=type=bind,source=package.json,target=package.json \
    npm install

# 让 CI 可以控制缓存层
docker build \
  --build-arg CACHE_BUST=$(date +%s) \
  --build-arg GIT_COMMIT=$CI_COMMIT_SHORT_SHA \
  -t myapp .