告别Dockerfile,拥抱 docker init 构建Docker镜像
概述
Docker 是一个开源的应用容器引擎，它允许开发者打包他们的应用以及依赖包到一个可移植的容器中，然后发布到任何流行的 Linux 机器上，也可以实现虚拟化。容器是完全使用沙箱机制，相互之间不会有任何接口，更重要的是容器性能开销极低。
什么是 docker init？
docker init 是一个命令行应用程序，可帮助初始化项目中的 Docker 资源。它根据项目的要求创建 Dockerfiles、docker-compose 文件和 .dockerignore 文件。这简化了为项目配置 Docker 的过程，节省时间并降低复杂性。
最新版本的 docker init 支持 Go、Python、Node.js、Rust、ASP.NET、PHP 和 Java。目前它只能于 Docker Desktop 一起使用，也就是说大家目前在 Linux 系统中是无法使用 docker init 的。
如何使用
使用 docker init 很简单，只需几个简单的步骤。首先，转到您要在其中设置 Docker 资源的项目目录。
举个例子，我来创建一个基本的 PHP 应用程序。
创建 index.php
<?php
echo 'Hello World! 开源技术小栈！';初始化
docker init 将扫描您的项目并要求您确认并选择最适合您的应用程序的模板。选择模板后docker init 会要求您提供一些特定于项目的信息，自动为您的项目生成必要的 Docker 资源。
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接下来要做的就是选择应用程序平台，在示例中使用 PHP。它将建议您的项目的推荐值，例如 PHP 版本、端口、入口点命令。
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您可以选择默认值或提供所需的值，它将创建您的 docker 配置文件以及动态运行应用程序的说明。让我们来看看这个自动生成的配置是什么样子。
$ ls
Dockerfile README.Docker.md compose.yaml index.php生成 Dockerfile 文件
# syntax=docker/dockerfile:1
# Comments are provided throughout this file to help you get started.
# If you need more help, visit the Dockerfile reference guide at
# https://docs.docker.com/go/dockerfile-reference/
################################################################################
# The example below uses the PHP Apache image as the foundation for running the app.
# By specifying the "7.4.28-apache" tag, it will also use whatever happens to be the
# most recent version of that tag when you build your Dockerfile.
# If reproducability is important, consider using a specific digest SHA, like
# php@sha256:99cede493dfd88720b610eb8077c8688d3cca50003d76d1d539b0efc8cca72b4.
FROM php:7.4.28-apache
# Copy app files from the app directory.
COPY . /var/www/html
# Your PHP application may require additional PHP extensions to be installed
# manually. For detailed instructions for installing extensions can be found, see
# https://github.com/docker-library/docs/tree/master/php#how-to-install-more-php-extensions
# The following code blocks provide examples that you can edit and use.
#
# Add core PHP extensions, see
# https://github.com/docker-library/docs/tree/master/php#php-core-extensions
# This example adds the apt packages for the 'gd' extension's dependencies and then
# installs the 'gd' extension. For additional tips on running apt-get:
# https://docs.docker.com/go/dockerfile-aptget-best-practices/
# RUN apt-get update && apt-get install -y \
# libfreetype-dev \
# libjpeg62-turbo-dev \
# libpng-dev \
# && rm -rf /var/lib/apt/lists/* \
# && docker-php-ext-configure gd --with-freetype --with-jpeg \
# && docker-php-ext-install -j$(nproc) gd
#
# Add PECL extensions, see
# https://github.com/docker-library/docs/tree/master/php#pecl-extensions
# This example adds the 'redis' and 'xdebug' extensions.
# RUN pecl install redis-5.3.7 \
# && pecl install xdebug-3.2.1 \
# && docker-php-ext-enable redis xdebug
# Use the default production configuration for PHP runtime arguments, see
# https://github.com/docker-library/docs/tree/master/php#configuration
RUN mv "$PHP_INI_DIR/php.ini-production" "$PHP_INI_DIR/php.ini"
# Switch to a non-privileged user (defined in the base image) that the app will run under.
# See https://docs.docker.com/go/dockerfile-user-best-practices/
USER www-data它遵循人们在所有 Linkedin 和 Medium 帖子中不断告诉我们的所有性能和安全最佳实践。
docker-compose.yml
# Comments are provided throughout this file to help you get started.
# If you need more help, visit the Docker compose reference guide at
# https://docs.docker.com/go/compose-spec-reference/
# Here the instructions define your application as a service called "server".
# This service is built from the Dockerfile in the current directory.
# You can add other services your application may depend on here, such as a
# database or a cache. For examples, see the Awesome Compose repository:
# https://github.com/docker/awesome-compose
services:
server:
build:
context: .
ports:
- 9009:80
# The commented out section below is an example of how to define a PostgreSQL
# database that your application can use. `depends_on` tells Docker Compose to
# start the database before your application. The `db-data` volume persists the
# database data between container restarts. The `db-password` secret is used
# to set the database password. You must create `db/password.txt` and add
# a password of your choosing to it before running `docker-compose up`.
# depends_on:
# db:
# condition: service_healthy
# db:
# image: postgres
# restart: always
# user: postgres
# secrets:
# - db-password
# volumes:
# - db-data:/var/lib/postgresql/data
# environment:
# - POSTGRES_DB=example
# - POSTGRES_PASSWORD_FILE=/run/secrets/db-password
# expose:
# - 5432
# healthcheck:
# test: [ "CMD", "pg_isready" ]
# interval: 10s
# timeout: 5s
# retries: 5
# volumes:
# db-data:
# secrets:
# db-password:
# file: db/password.txt它编写了 docker-compose.yaml 配置来运行应用程序。由于我们的应用程序不包含与数据库的任何连接，因此它注释掉了数据库容器可能需要的代码。
构建镜像
docker compose up --build' fill='%23FFFFFF'%3E%3Crect x='249' y='126' width='1' height='1'%3E%3C/rect%3E%3C/g%3E%3C/g%3E%3C/svg%3E)
运行容器
' fill='%23FFFFFF'%3E%3Crect x='249' y='126' width='1' height='1'%3E%3C/rect%3E%3C/g%3E%3C/g%3E%3C/svg%3E)
[+] Running 1/1
✔ Container init-server-1 Recreated 0.2s
Attaching to server-1
server-1 | AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.19.0.2. Set the 'ServerName' directive globally to suppress this message
server-1 | AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.19.0.2. Set the 'ServerName' directive globally to suppress this message
server-1 | [Wed Apr 17 15:36:35.110763 2024] [mpm_prefork:notice] [pid 1] AH00163: Apache/2.4.53 (Debian) PHP/7.4.28 configured -- resuming normal operations
server-1 | [Wed Apr 17 15:36:35.110809 2024] [core:notice] [pid 1] AH00094: Command line: 'apache2 -D FOREGROUND'
server-1 | 172.19.0.1 - - [17/Apr/2024:15:36:39 +0000] "GET / HTTP/1.1" 200 208 "-" "curl/7.70.0"
server-1 | 172.19.0.1 - - [17/Apr/2024:15:37:18 +0000] "GET / HTTP/1.1" 200 208 "-" "curl/7.70.0"
server-1 | 172.19.0.1 - - [17/Apr/2024:15:37:19 +0000] "GET / HTTP/1.1" 200 208 "-" "curl/7.70.0"
server-1 | 172.19.0.1 - - [17/Apr/2024:15:37:19 +0000] "GET / HTTP/1.1" 200 208 "-" "curl/7.70.0"请求访问
$ curl http://127.0.0.1:9009/
Hello World !
$ curl http://127.0.0.1:9009/
Hello World! 开源技术小栈！为什么使用 docker init？
docker init 使 Docker 化变得轻而易举，特别是对于 Docker 新手来说。它消除了编写 Dockerfile 和其他配置文件的手动任务，从而节省时间并最大限度地减少错误。它使用模板根据您的应用程序类型自定义 Docker 设置，同时遵循行业最佳实践。