Docker镜像安装Node.js 14后npm缺失的问题求助

问题背景 #

我用以下Dockerfile构建同时包含Python 3.8和Node.js 14的镜像：

FROM python:3.8-slim

ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
ENV DJANGO_DEVELOPMENT 1

#Installing neccessary packages
RUN apt-get update && apt-get install -y git curl virtualenv default-mysql-server default-mysql-client
RUN curl -sL https://deb.nodesource.com/setup_14.x | bash -
RUN apt-get install nodejs -y
RUN npm install -g @vue/cli

#Installing Python dependencies
RUN pip install --upgrade pip && pip install nodeenv

按照预期，通过curl -sL https://deb.nodesource.com/setup_14.x | bash -和apt-get install nodejs -y应该同时安装Node.js和npm，但执行docker build .时出现报错，提示找不到npm：

=> [internal] load build definition from dev.Dockerfile                                                                                                           0.1s 
 => => transferring dockerfile: 482B                                                                                                                               0.0s 
 => [internal] load .dockerignore                                                                                                                                  0.0s 
 => => transferring context: 2B                                                                                                                                    0.0s
 => [internal] load metadata for docker.io/library/python:3.8-slim                                                                                                 0.4s
 => [1/6] FROM docker.io/library/python:3.8-slim@sha256:10e07e36f86af4371accc42642852aa60eab74e6896fc065345ebc2c576eec0d                                           0.0s
 => CACHED [2/6] RUN apt-get update && apt-get install -y git curl virtualenv default-mysql-server default-mysql-client                                            0.0s
 => CACHED [3/6] RUN curl -sL https://deb.nodesource.com/setup_14.x | bash -                                                                                       0.0s
 => CACHED [4/6] RUN apt-get install nodejs -y                                                                                                                     0.0s
 => ERROR [5/6] RUN npm install -g @vue/cli                                                                                                                        0.3s
------                                                                                                                                                                  
 > [5/6] RUN npm install -g @vue/cli:
#0 0.267 /bin/sh: 1: npm: not found
------
dev.Dockerfile:11
--------------------
   9 |     RUN curl -sL https://deb.nodesource.com/setup_14.x | bash -
  10 |     RUN apt-get install nodejs -y
  11 | >>> RUN npm install -g @vue/cli
  12 |     
  13 |     #Installing Python dependencies
--------------------
ERROR: failed to solve: process "/bin/sh -c npm install -g @vue/cli" did not complete successfully: exit code: 127

我的package.json内容如下：

{
  "name": "name",
  "version": "0.1.0",
  "private": true,
  "resolutions": {
    "glob-parent": "^5.1.2",
    "node-forge": "1.3.0",
    "ansi-regex": "5.0.1",
    "ejs": "3.1.7"
  },
  "scripts": {
    "preinstall": "npx npm-force-resolutions",
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "test:unit": "vue-cli-service test:unit --setupTestFrameworkScriptFile=./tests/setup.js",
    "lint": "vue-cli-service lint"
  },
  "dependencies": {
    "axios": "^0.24.0",
    "core-js": "^3.22.7",
    "js-cookie": "^3.0.1",
    "vue": "^2.6.11",
    "vue-pdf-app": "^2.1.0",
    "vue-router": "^3.5.4",
    "vue-spinner": "^1.0.4",
    "vuetify": "^2.6.6"
  },
  "devDependencies": {
    "@vue/cli-plugin-babel": "~4.5.0",
    "@vue/cli-plugin-eslint": "~4.5.0",
    "@vue/cli-plugin-router": "~4.5.0",
    "@vue/cli-plugin-unit-jest": "~4.5.0",
    "@vue/cli-service": "~4.5.0",
    "@vue/eslint-config-airbnb": "^5.0.2",
    "@vue/test-utils": "^1.0.3",
    "babel-eslint": "^10.1.0",
    "eslint": "^6.7.2",
    "eslint-plugin-import": "^2.26.0",
    "eslint-plugin-vue": "^6.2.2",
    "sass": "~1.32.0",
    "sass-loader": "^10.2.1",
    "vue-cli-plugin-vuetify": "^2.4.8",
    "vue-template-compiler": "^2.6.11",
    "vuetify-loader": "^1.7.0"
  },
  "eslintConfig": {
    "rules": {
      "no-console": "off"
    }
  }
}

尝试过添加RUN apt-get install npm，但会安装不兼容的npm版本，导致后续代码报错。

解决方案 #

1. 清理Docker缓存后重新构建 #

当前构建过程中[3/6]和[4/6]步骤显示CACHED，说明Docker复用了之前的缓存层，可能之前的安装未正确完成npm部署。执行以下命令清理缓存后重新构建：

docker builder prune
docker build .

2. 修改Dockerfile，合并安装命令 #

将Node.js相关安装步骤合并到一个RUN指令中，避免缓存导致的流程断裂，同时添加镜像优化操作：

FROM python:3.8-slim

ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
ENV DJANGO_DEVELOPMENT 1

# 安装依赖包及Node.js 14
RUN apt-get update && apt-get install -y --no-install-recommends \
    git curl virtualenv default-mysql-server default-mysql-client \
    && curl -sL https://deb.nodesource.com/setup_14.x | bash - \
    && apt-get install -y nodejs \
    && npm install -g @vue/cli \
    # 清理apt缓存以减小镜像体积
    && apt-get clean \
    && rm -rf /var/lib/apt/lists/*

# 安装Python依赖
RUN pip install --upgrade pip && pip install nodeenv

3. 验证安装完整性（可选） #

可以在Dockerfile中添加验证步骤，确保Node.js和npm安装成功：

RUN node --version && npm --version

说明 #

• 合并RUN指令能避免Docker缓存中间层导致的安装不完整问题，确保Node.js与npm的安装流程连贯执行。
• nodesource的setup脚本会配置对应版本的软件源，安装的nodejs包已包含兼容的npm，无需单独安装系统默认的npm包。
• 清理apt缓存是Docker镜像优化的常规操作，可有效减小镜像体积。

内容的提问来源于stack exchange，提问作者hjbello