The quieter you become, the more you are able to hear.
Spring Security 是一个轻量级的安全框架，可以和 Spring 项目很好地集成，提供了丰富的身份认证和授权相关的功能，而且还能防止一些常见的网络攻击。我在工作中有很多项目都使用了 Spring Security 框架，但基本上都是浅尝辄止，按照说明文档配置好就完事了，一直没有时间深入地研究过。最近在 Reflectoring 上看到了一篇文章 Getting started with Spring Security and Spring Boot，写得非常全面仔细，感觉是一篇不错的 Spring Security 入门文章，于是花了一点时间拜读了一番，结合着 官方文档 和 源码 系统地学习一下 Spring Security 的实现原理。入门示例我们先从一个简单的例子开始，这里我直接使用了 使用 Spring 项目脚手架 中的 Hello World 示例。为了让这个示例程序开启 Spring Security 功能，我们在 pom.xml 文件中引入 spring-boot-starter-security 依赖即可：<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-security</artifactId> </dependency>启动程序，会在控制台日志中看到类似下面这样的信息：2023-05-15 06:52:52.418 INFO 8596 --- [ main] .s.s.UserDetailsServiceAutoConfiguration : Using generated security password: eeb386a9-e16a-4b9b-bbc6-c054c8d263b0这个是由 Spring Security 随机生成的密码。访问 /hello 页面，可以看到出现了一个登录页面：输入用户名（默认为 user）和密码（控制台日志）登录成功后我们才能正常访问页面。默认的用户名和密码可以使用下面的配置进行修改：spring.security.user.name=admin spring.security.user.password=123456为了后续更好地对 Spring Security 进行配置，理解 Spring Security 的实现原理，我们需要进一步学习 Spring Security 的三大核心组件：过滤器（Servlet Filters）认证（Authentication）授权（Authorization）Servlet Filters：Spring Security 的基础我们知道，在 Spring MVC 框架中，DispatcherServlet 负责对用户的 Web 请求进行分发和处理，在请求到达 DispatcherServlet 之前，会经过一系列的 Servlet Filters，这被称之为过滤器，主要作用是拦截请求并对请求做一些前置或后置处理。这些过滤器串在一起，形成一个过滤器链（FilterChain）：我们可以在配置文件中加上下面的日志配置：logging.level.org.springframework.boot.web.servlet.ServletContextInitializerBeans=TRACE然后重新启动服务，会在控制台输出类似下面这样的日志（为了方便查看，我做了一点格式化）：2023-05-18 07:08:14.805 TRACE 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Added existing Filter initializer bean 'webMvcMetricsFilter'; order=-2147483647, resource=class path resource [org/springframework/boot/actuate/autoconfigure/metrics/web/servlet/WebMvcMetricsAutoConfiguration.class] 2023-05-18 07:08:14.806 TRACE 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Added existing Filter initializer bean 'securityFilterChainRegistration'; order=-100, resource=class path resource [org/springframework/boot/autoconfigure/security/servlet/SecurityFilterAutoConfiguration.class] 2023-05-18 07:08:14.808 TRACE 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Added existing Servlet initializer bean 'dispatcherServletRegistration'; order=2147483647, resource=class path resource [org/springframework/boot/autoconfigure/web/servlet/DispatcherServletAutoConfiguration$DispatcherServletRegistrationConfiguration.class] 2023-05-18 07:08:14.810 TRACE 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Added existing Filter initializer bean 'errorPageSecurityFilter'; order=2147483647, resource=class path resource [org/springframework/boot/autoconfigure/security/servlet/SpringBootWebSecurityConfiguration$ErrorPageSecurityFilterConfiguration.class] 2023-05-18 07:08:14.813 TRACE 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Added existing ServletContextInitializer initializer bean 'servletEndpointRegistrar'; order=2147483647, resource=class path resource [org/springframework/boot/actuate/autoconfigure/endpoint/web/ServletEndpointManagementContextConfiguration$WebMvcServletEndpointManagementContextConfiguration.class] 2023-05-18 07:08:14.828 TRACE 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Created Filter initializer for bean 'characterEncodingFilter'; order=-2147483648, resource=class path resource [org/springframework/boot/autoconfigure/web/servlet/HttpEncodingAutoConfiguration.class] 2023-05-18 07:08:14.831 TRACE 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Created Filter initializer for bean 'formContentFilter'; order=-9900, resource=class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration.class] 2023-05-18 07:08:14.834 TRACE 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Created Filter initializer for bean 'requestContextFilter'; order=-105, resource=class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class] 2023-05-18 07:08:14.842 DEBUG 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Mapping filters: filterRegistrationBean urls=[/*] order=-2147483647, springSecurityFilterChain urls=[/*] order=-100, filterRegistrationBean urls=[/*] order=2147483647, characterEncodingFilter urls=[/*] order=-2147483648, formContentFilter urls=[/*] order=-9900, requestContextFilter urls=[/*] order=-105 2023-05-18 07:08:14.844 DEBUG 10020 --- [ main] o.s.b.w.s.ServletContextInitializerBeans : Mapping servlets: dispatcherServlet urls=[/] 这里显示了应用开启的所有 Filter 以及对应的自动配置类，可以看到 Spring Security 自动注入了两个 FilterRegistrationBean：来自配置类 SecurityFilterAutoConfiguration 的 securityFilterChainRegistration来自配置类 ErrorPageSecurityFilterConfiguration 的 errorPageSecurityFilterDelegatingFilterProxy：Servlet Filter 与 Spring Bean 的桥梁注意上面显示的并非 Filter 的名字，而是 FilterRegistrationBean 的名字，这是一种 RegistrationBean，它实现了 ServletContextInitializer 接口，用于在程序启动时，将 Filter 或 Servlet 注入到 ServletContext 中：public abstract class RegistrationBean implements ServletContextInitializer, Ordered { @Override public final void onStartup(ServletContext servletContext) throws ServletException { ... register(description, servletContext); } }其中 securityFilterChainRegistration 的定义如下：@Bean @ConditionalOnBean(name = DEFAULT_FILTER_NAME) public DelegatingFilterProxyRegistrationBean securityFilterChainRegistration( SecurityProperties securityProperties) { DelegatingFilterProxyRegistrationBean registration = new DelegatingFilterProxyRegistrationBean( DEFAULT_FILTER_NAME); registration.setOrder(securityProperties.getFilter().getOrder()); registration.setDispatcherTypes(getDispatcherTypes(securityProperties)); return registration; }这个 RegistrationBean 的类型为 DelegatingFilterProxyRegistrationBean，由它注入的 Filter 叫 DelegatingFilterProxy：public class DelegatingFilterProxyRegistrationBean extends AbstractFilterRegistrationBean<DelegatingFilterProxy> { ... }这是一个非常重要的 Servlet Filter，它充当着 Servlet 容器和 Spring 上下文之间的桥梁，由于 Servlet 容器有着它自己的标准，在注入 Filter 时并不知道 Spring Bean 的存在，所以我们可以通过 DelegatingFilterProxy 来实现 Bean Filter 的延迟加载：看一下 DelegatingFilterProxy 的实现：public class DelegatingFilterProxy extends GenericFilterBean { @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws ServletException, IOException { // Lazily initialize the delegate if necessary. Filter delegateToUse = this.delegate; if (delegateToUse == null) { synchronized (this.delegateMonitor) { delegateToUse = this.delegate; if (delegateToUse == null) { WebApplicationContext wac = findWebApplicationContext(); if (wac == null) { throw new IllegalStateException("No WebApplicationContext found: " + "no ContextLoaderListener or DispatcherServlet registered?"); } delegateToUse = initDelegate(wac); } this.delegate = delegateToUse; } } // Let the delegate perform the actual doFilter operation. invokeDelegate(delegateToUse, request, response, filterChain); } }这段代码很容易理解，首先判断代理的 Bean Filter 是否存在，如果不存在则根据 findWebApplicationContext() 找到 Web 应用上下文，然后从上下文中获取 Bean Filter 并初始化，最后再调用该 Bean Filter。FilterChainProxy：Spring Security 的统一入口那么接下来的问题是，这个 DelegatingFilterProxy 代理的 Bean Filter 是什么呢？我们从上面定义 DelegatingFilterProxyRegistrationBean 的地方可以看出，代理的 Bean Filter 叫做 DEFAULT_FILTER_NAME，查看它的定义就知道，实际上就是 springSecurityFilterChain：public static final String DEFAULT_FILTER_NAME = "springSecurityFilterChain";那么这个 springSecurityFilterChain 是在哪定义的呢？我们可以在 WebSecurityConfiguration 配置类中找到答案：public class WebSecurityConfiguration { @Bean(name = AbstractSecurityWebApplicationInitializer.DEFAULT_FILTER_NAME) public Filter springSecurityFilterChain() throws Exception { boolean hasConfigurers = this.webSecurityConfigurers != null && !this.webSecurityConfigurers.isEmpty(); boolean hasFilterChain = !this.securityFilterChains.isEmpty(); if (!hasConfigurers && !hasFilterChain) { WebSecurityConfigurerAdapter adapter = this.objectObjectPostProcessor .postProcess(new WebSecurityConfigurerAdapter() { }); this.webSecurity.apply(adapter); } for (SecurityFilterChain securityFilterChain : this.securityFilterChains) { this.webSecurity.addSecurityFilterChainBuilder(() -> securityFilterChain); for (Filter filter : securityFilterChain.getFilters()) { if (filter instanceof FilterSecurityInterceptor) { this.webSecurity.securityInterceptor((FilterSecurityInterceptor) filter); break; } } } for (WebSecurityCustomizer customizer : this.webSecurityCustomizers) { customizer.customize(this.webSecurity); } return this.webSecurity.build(); } }很显然，springSecurityFilterChain 经过一系列的安全配置，最后通过 this.webSecurity.build() 构建出来的，进一步深入到 webSecurity 的源码我们就可以发现它的类型是 FilterChainProxy：public final class WebSecurity extends AbstractConfiguredSecurityBuilder<Filter, WebSecurity> implements SecurityBuilder<Filter>, ApplicationContextAware, ServletContextAware { @Override protected Filter performBuild() throws Exception { int chainSize = this.ignoredRequests.size() + this.securityFilterChainBuilders.size(); List<SecurityFilterChain> securityFilterChains = new ArrayList<>(chainSize); List<RequestMatcherEntry<List<WebInvocationPrivilegeEvaluator>>> requestMatcherPrivilegeEvaluatorsEntries = new ArrayList<>(); for (RequestMatcher ignoredRequest : this.ignoredRequests) { SecurityFilterChain securityFilterChain = new DefaultSecurityFilterChain(ignoredRequest); securityFilterChains.add(securityFilterChain); requestMatcherPrivilegeEvaluatorsEntries .add(getRequestMatcherPrivilegeEvaluatorsEntry(securityFilterChain)); } for (SecurityBuilder<? extends SecurityFilterChain> securityFilterChainBuilder : this.securityFilterChainBuilders) { SecurityFilterChain securityFilterChain = securityFilterChainBuilder.build(); securityFilterChains.add(securityFilterChain); requestMatcherPrivilegeEvaluatorsEntries .add(getRequestMatcherPrivilegeEvaluatorsEntry(securityFilterChain)); } FilterChainProxy filterChainProxy = new FilterChainProxy(securityFilterChains); if (this.httpFirewall != null) { filterChainProxy.setFirewall(this.httpFirewall); } if (this.requestRejectedHandler != null) { filterChainProxy.setRequestRejectedHandler(this.requestRejectedHandler); } filterChainProxy.afterPropertiesSet(); Filter result = filterChainProxy; this.postBuildAction.run(); return result; } }从 FilterChainProxy 的名字可以看出来，它也是一个代理类，它代理的类叫做 SecurityFilterChain，它包含了多个 Security Filters 形成一个过滤器链，这和 Servlet Filters 有点类似，只不过这些 Security Filters 都是普通的 Spring Bean：使用 FilterChainProxy 来代理 Security Filters 相比于直接使用 Servlet Filters 或使用 DelegatingFilterProxy 来代理有几个明显的好处：FilterChainProxy 作为 Spring Security 对 Servlet 的支持入口，方便理解和调试；FilterChainProxy 可以对 Spring Security 做一些集中处理，比如统一清除 SecurityContext 防止内存泄漏，以及统一使用 HttpFirewall 对应用进行保护等；支持多个 SecurityFilterChain，传统的 Servlet Filters 只能通过 URL 来匹配，使用 FilterChainProxy 可以配合 RequestMatcher 更灵活地控制调用哪个 SecurityFilterChain；构建 SecurityFilterChain上面讲到，FilterChainProxy 是通过 webSecurity 构建的，一个 FilterChainProxy 里包含一个或多个 SecurityFilterChain，那么 SecurityFilterChain 是由谁构建的呢？答案是 httpSecurity。我们可以在 SecurityFilterChainConfiguration 配置类中看到 SecurityFilterChain 的构建过程：@Configuration(proxyBeanMethods = false) @ConditionalOnDefaultWebSecurity static class SecurityFilterChainConfiguration { @Bean @Order(SecurityProperties.BASIC_AUTH_ORDER) SecurityFilterChain defaultSecurityFilterChain(HttpSecurity http) throws Exception { http.authorizeRequests().anyRequest().authenticated(); http.formLogin(); http.httpBasic(); return http.build(); } }深入到 http.build() 的源码，可以看到过滤器链的默认实现为 DefaultSecurityFilterChain：public final class HttpSecurity extends AbstractConfiguredSecurityBuilder<DefaultSecurityFilterChain, HttpSecurity> implements SecurityBuilder<DefaultSecurityFilterChain>, HttpSecurityBuilder<HttpSecurity> { @SuppressWarnings("unchecked") @Override protected DefaultSecurityFilterChain performBuild() { this.filters.sort(OrderComparator.INSTANCE); List<Filter> sortedFilters = new ArrayList<>(this.filters.size()); for (Filter filter : this.filters) { sortedFilters.add(((OrderedFilter) filter).filter); } return new DefaultSecurityFilterChain(this.requestMatcher, sortedFilters); } }构建 Security Filters通过上面的梳理，我们大概清楚了 SecurityFilterChain 的构建过程，接下来，我们继续看 Security Filters 的构建过程。我们知道，一个SecurityFilterChain 中包含了多个 Security Filters，那么这些 Security Filters 是从哪里来的呢？在 HttpSecurity 的代码里可以找到这么几个方法：public HttpSecurity addFilter(Filter filter)public HttpSecurity addFilterBefore(Filter filter, Class<? extends Filter> beforeFilter)public HttpSecurity addFilterAfter(Filter filter, Class<? extends Filter> afterFilter)public HttpSecurity addFilterAt(Filter filter, Class<? extends Filter> atFilter)我们不妨在 addFilter 方法内下个断点，然后以调试模式启动程序，每次触发断点时，我们将对应的 Filter 记录下来，并通过堆栈找到该 Filter 是从何处添加的：序号Filter来源1WebAsyncManagerIntegrationFilterHttpSecurityConfiguration.httpSecurity()2CsrfFilterCsrfConfigurer.configure()3ExceptionTranslationFilterExceptionHandlingConfigurer.configure()4HeaderWriterFilterHeadersConfigurer.configure()5SessionManagementFilterSessionManagementConfigurer.configure()6DisableEncodeUrlFilterSessionManagementConfigurer.configure()7SecurityContextPersistenceFilterSecurityContextConfigurer.configure()8RequestCacheAwareFilterRequestCacheConfigurer.configure()9AnonymousAuthenticationFilterAnonymousConfigurer.configure()10SecurityContextHolderAwareRequestFilterServletApiConfigurer.configure()11DefaultLoginPageGeneratingFilterDefaultLoginPageConfigurer.configure()12DefaultLogoutPageGeneratingFilterDefaultLoginPageConfigurer.configure()13LogoutFilterLogoutConfigurer.configure()14FilterSecurityInterceptorAbstractInterceptUrlConfigurer.configure()15UsernamePasswordAuthenticationFilterAbstractAuthenticationFilterConfigurer.configure()16BasicAuthenticationFilterHttpBasicConfigurer.configure()除了第一个 WebAsyncManagerIntegrationFilter 是在创建 HttpSecurity 的时候直接添加的，其他的 Filter 都是通过 XXXConfigurer 这样的配置器添加的。我们继续深挖下去可以发现，生成这些配置器的地方有两个，第一个地方是在 HttpSecurityConfiguration 配置类中创建 HttpSecurity 时，如下所示：class HttpSecurityConfiguration { @Bean(HTTPSECURITY_BEAN_NAME) @Scope("prototype") HttpSecurity httpSecurity() throws Exception { WebSecurityConfigurerAdapter.LazyPasswordEncoder passwordEncoder = new WebSecurityConfigurerAdapter.LazyPasswordEncoder( this.context); AuthenticationManagerBuilder authenticationBuilder = new WebSecurityConfigurerAdapter.DefaultPasswordEncoderAuthenticationManagerBuilder( this.objectPostProcessor, passwordEncoder); authenticationBuilder.parentAuthenticationManager(authenticationManager()); authenticationBuilder.authenticationEventPublisher(getAuthenticationEventPublisher()); HttpSecurity http = new HttpSecurity(this.objectPostProcessor, authenticationBuilder, createSharedObjects()); // @formatter:off http .csrf(withDefaults()) .addFilter(new WebAsyncManagerIntegrationFilter()) .exceptionHandling(withDefaults()) .headers(withDefaults()) .sessionManagement(withDefaults()) .securityContext(withDefaults()) .requestCache(withDefaults()) .anonymous(withDefaults()) .servletApi(withDefaults()) .apply(new DefaultLoginPageConfigurer<>()); http.logout(withDefaults()); // @formatter:on applyDefaultConfigurers(http); return http; } }另外一个地方则是在上面的 SecurityFilterChainConfiguration 配置类中使用 http.build() 构建 SecurityFilterChain 之前（参见上面 defaultSecurityFilterChain 的代码），至此，我们大概理清了所有的 Security Filters 是如何创建的，下面再以表格的形式重新整理下：序号FilterhttpSecurity 配置1WebAsyncManagerIntegrationFilterhttp.addFilter(new WebAsyncManagerIntegrationFilter())2CsrfFilterhttp.csrf(withDefaults())3ExceptionTranslationFilterhttp.exceptionHandling(withDefaults())4HeaderWriterFilterhttp.headers(withDefaults())5SessionManagementFilterhttp.sessionManagement(withDefaults())6DisableEncodeUrlFilterhttp.sessionManagement(withDefaults())7SecurityContextPersistenceFilterhttp.securityContext(withDefaults())8RequestCacheAwareFilterhttp.requestCache(withDefaults())9AnonymousAuthenticationFilterhttp.anonymous(withDefaults())10SecurityContextHolderAwareRequestFilterhttp.servletApi(withDefaults())11DefaultLoginPageGeneratingFilterhttp.apply(new DefaultLoginPageConfigurer<>())12DefaultLogoutPageGeneratingFilterhttp.apply(new DefaultLoginPageConfigurer<>())13LogoutFilterhttp.logout(withDefaults())14FilterSecurityInterceptorhttp.authorizeRequests().anyRequest().authenticated()15UsernamePasswordAuthenticationFilterhttp.formLogin()16BasicAuthenticationFilterhttp.httpBasic()其实，如果仔细观察我们的程序输出的日志，也可以看到 Spring Security 默认的过滤器链为 DefaultSecurityFilterChain，以及它注入的所有 Security Filters：2023-05-17 08:16:18.173 INFO 3936 --- [ main] o.s.s.web.DefaultSecurityFilterChain : Will secure any request with [ org.springframework.security.web.session.DisableEncodeUrlFilter@1d6751e3, org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter@2d258eff, org.springframework.security.web.context.SecurityContextPersistenceFilter@202898d7, org.springframework.security.web.header.HeaderWriterFilter@2c26ba07, org.springframework.security.web.csrf.CsrfFilter@52d3fafd, org.springframework.security.web.authentication.logout.LogoutFilter@235c997d, org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter@5d5c41e5, org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter@50b93353, org.springframework.security.web.authentication.ui.DefaultLogoutPageGeneratingFilter@6dca31eb, org.springframework.security.web.authentication.www.BasicAuthenticationFilter@22825e1e, org.springframework.security.web.savedrequest.RequestCacheAwareFilter@2c719bd4, org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter@53aa38be, org.springframework.security.web.authentication.AnonymousAuthenticationFilter@4a058df8, org.springframework.security.web.session.SessionManagementFilter@42ea7565, org.springframework.security.web.access.ExceptionTranslationFilter@77cb452c, org.springframework.security.web.access.intercept.FilterSecurityInterceptor@8054fe2]在某些低版本中，可能会显示 DefaultSecurityFilterChain: Will not secure any request 这样的日志，这可能是 Spring Security 的 BUG，升级到最新版本即可。其中有几个 Security Filters 比较重要，是实现认证和授权的基础：CsrfFilter：默认开启对所有接口的 CSRF 防护，关于 CSRF 的详细信息，可以参考 Configuring CSRF/XSRF with Spring Security；DefaultLoginPageGeneratingFilter：用于生成 /login 登录页面；DefaultLogoutPageGeneratingFilter：用于生成 /login?logout 登出页面；LogoutFilter：当用户退出应用时被调用，它通过注册的 LogoutHandler 删除会话并清理 SecurityContext，然后通过 LogoutSuccessHandler 将页面重定向到 /login?logout；UsernamePasswordAuthenticationFilter：实现基于用户名和密码的安全认证，当认证失败，抛出 AuthenticationException 异常；BasicAuthenticationFilter：实现 Basic 安全认证，当认证失败，抛出 AuthenticationException 异常；AnonymousAuthenticationFilter：如果 SecurityContext 中没有 Authentication 对象时，它自动创建一个匿名用户 anonymousUser，角色为 ROLE_ANONYMOUS；FilterSecurityInterceptor：这是 Spring Security 的最后一个 Security Filters，它从 SecurityContext 中获取 Authentication 对象，然后对请求的资源做权限判断，当授权失败，抛出 AccessDeniedException 异常；ExceptionTranslationFilter：用于处理过滤器链中抛出的 AuthenticationException 和 AccessDeniedException 异常，AuthenticationException 异常由 AuthenticationEntryPoint 来处理，AccessDeniedException 异常由 AccessDeniedHandler 来处理；认证和授权有了 Security Filters，我们就可以实现各种 Spring Security 的相关功能了。应用程序的安全性归根结底包括了两个主要问题：认证（Authentication） 和 授权（Authorization）。认证解决的是 你是谁？ 的问题，而授权负责解决 你被允许做什么？，授权也被称为 访问控制（Access Control）。这一节将深入学习 Spring Security 是如何实现认证和授权的。跳转到 /login 页面让我们回到第一节的例子，当访问 /hello 时，可以看到浏览器自动跳转到了 /login 登录页面，那么 Spring Security 是如何实现的呢？为了一探究竟，我们可以将 Spring Security 的日志级别调到 TRACE：logging.level.org.springframework.security=TRACE这样我们就能完整地看到这个请求经过 Security Filters 的处理过程：2023-05-20 09:37:38.558 DEBUG 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Securing GET /hello 2023-05-20 09:37:38.559 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking DisableEncodeUrlFilter (1/17) 2023-05-20 09:37:38.559 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking WebAsyncManagerIntegrationFilter (2/17) 2023-05-20 09:37:38.560 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking SecurityContextPersistenceFilter (3/17) 2023-05-20 09:37:38.561 TRACE 6632 --- [nio-8080-exec-9] w.c.HttpSessionSecurityContextRepository : No HttpSession currently exists 2023-05-20 09:37:38.561 TRACE 6632 --- [nio-8080-exec-9] w.c.HttpSessionSecurityContextRepository : Created SecurityContextImpl [Null authentication] 2023-05-20 09:37:38.562 DEBUG 6632 --- [nio-8080-exec-9] s.s.w.c.SecurityContextPersistenceFilter : Set SecurityContextHolder to empty SecurityContext 2023-05-20 09:37:38.562 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking HeaderWriterFilter (4/17) 2023-05-20 09:37:38.562 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking CorsFilter (5/17) 2023-05-20 09:37:38.566 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking CsrfFilter (6/17) 2023-05-20 09:37:38.567 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.csrf.CsrfFilter : Did not protect against CSRF since request did not match CsrfNotRequired [TRACE, HEAD, GET, OPTIONS] 2023-05-20 09:37:38.568 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking LogoutFilter (7/17) 2023-05-20 09:37:38.571 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.a.logout.LogoutFilter : Did not match request to Ant [pattern='/logout', POST] 2023-05-20 09:37:38.573 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking UsernamePasswordAuthenticationFilter (8/17) 2023-05-20 09:37:38.574 TRACE 6632 --- [nio-8080-exec-9] w.a.UsernamePasswordAuthenticationFilter : Did not match request to Ant [pattern='/login', POST] 2023-05-20 09:37:38.576 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking DefaultLoginPageGeneratingFilter (9/17) 2023-05-20 09:37:38.578 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking DefaultLogoutPageGeneratingFilter (10/17) 2023-05-20 09:37:38.582 TRACE 6632 --- [nio-8080-exec-9] .w.a.u.DefaultLogoutPageGeneratingFilter : Did not render default logout page since request did not match [Ant [pattern='/logout', GET]] 2023-05-20 09:37:38.583 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking BasicAuthenticationFilter (11/17) 2023-05-20 09:37:38.584 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.a.www.BasicAuthenticationFilter : Did not process authentication request since failed to find username and password in Basic Authorization header 2023-05-20 09:37:38.587 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking RequestCacheAwareFilter (12/17) 2023-05-20 09:37:38.588 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.s.HttpSessionRequestCache : No saved request 2023-05-20 09:37:38.590 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking SecurityContextHolderAwareRequestFilter (13/17) 2023-05-20 09:37:38.591 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking AnonymousAuthenticationFilter (14/17) 2023-05-20 09:37:38.592 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.a.AnonymousAuthenticationFilter : Set SecurityContextHolder to AnonymousAuthenticationToken [Principal=anonymousUser, Credentials=[PROTECTED], Authenticated=true, Details=WebAuthenticationDetails [RemoteIpAddress=127.0.0.1, SessionId=null], Granted Authorities=[ROLE_ANONYMOUS]] 2023-05-20 09:37:38.593 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking SessionManagementFilter (15/17) 2023-05-20 09:37:38.593 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking ExceptionTranslationFilter (16/17) 2023-05-20 09:37:38.594 TRACE 6632 --- [nio-8080-exec-9] o.s.security.web.FilterChainProxy : Invoking FilterSecurityInterceptor (17/17) 2023-05-20 09:37:38.596 TRACE 6632 --- [nio-8080-exec-9] edFilterInvocationSecurityMetadataSource : Did not match request to EndpointRequestMatcher includes=[health], excludes=[], includeLinks=false - [permitAll] (1/2) 2023-05-20 09:37:38.610 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.a.i.FilterSecurityInterceptor : Did not re-authenticate AnonymousAuthenticationToken [Principal=anonymousUser, Credentials=[PROTECTED], Authenticated=true, Details=WebAuthenticationDetails [RemoteIpAddress=127.0.0.1, SessionId=null], Granted Authorities=[ROLE_ANONYMOUS]] before authorizing 2023-05-20 09:37:38.619 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.a.i.FilterSecurityInterceptor : Authorizing filter invocation [GET /hello] with attributes [authenticated] 2023-05-20 09:37:38.626 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.a.expression.WebExpressionVoter : Voted to deny authorization 2023-05-20 09:37:38.632 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.a.i.FilterSecurityInterceptor : Failed to authorize filter invocation [GET /hello] with attributes [authenticated] using AffirmativeBased [DecisionVoters=[org.springframework.security.web.access.expression.WebExpressionVoter@f613067], AllowIfAllAbstainDecisions=false] 2023-05-20 09:37:38.640 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.a.ExceptionTranslationFilter : Sending AnonymousAuthenticationToken [Principal=anonymousUser, Credentials=[PROTECTED], Authenticated=true, Details=WebAuthenticationDetails [RemoteIpAddress=127.0.0.1, SessionId=null], Granted Authorities=[ROLE_ANONYMOUS]] to authentication entry point since access is denied org.springframework.security.access.AccessDeniedException: Access is denied at org.springframework.security.access.vote.AffirmativeBased.decide(AffirmativeBased.java:73) ~[spring-security-core-5.7.8.jar:5.7.8] 2023-05-20 09:37:38.691 DEBUG 6632 --- [nio-8080-exec-9] o.s.s.w.s.HttpSessionRequestCache : Saved request http://localhost:8080/hello to session 2023-05-20 09:37:38.693 DEBUG 6632 --- [nio-8080-exec-9] s.w.a.DelegatingAuthenticationEntryPoint : Trying to match using And [Not [RequestHeaderRequestMatcher [expectedHeaderName=X-Requested-With, expectedHeaderValue=XMLHttpRequest]], MediaTypeRequestMatcher [contentNegotiationStrategy=org.springframework.web.accept.HeaderContentNegotiationStrategy@4b95451, matchingMediaTypes=[application/xhtml+xml, image/*, text/html, text/plain], useEquals=false, ignoredMediaTypes=[*/*]]] 2023-05-20 09:37:38.701 DEBUG 6632 --- [nio-8080-exec-9] s.w.a.DelegatingAuthenticationEntryPoint : Match found! Executing org.springframework.security.web.authentication.LoginUrlAuthenticationEntryPoint@168ad26f 2023-05-20 09:37:38.709 DEBUG 6632 --- [nio-8080-exec-9] o.s.s.web.DefaultRedirectStrategy : Redirecting to http://localhost:8080/login 2023-05-20 09:37:38.712 TRACE 6632 --- [nio-8080-exec-9] o.s.s.w.header.writers.HstsHeaderWriter : Not injecting HSTS header since it did not match request to [Is Secure] 2023-05-20 09:37:38.720 DEBUG 6632 --- [nio-8080-exec-9] w.c.HttpSessionSecurityContextRepository : Did not store empty SecurityContext 2023-05-20 09:37:38.730 DEBUG 6632 --- [nio-8080-exec-9] w.c.HttpSessionSecurityContextRepository : Did not store empty SecurityContext 2023-05-20 09:37:38.731 DEBUG 6632 --- [nio-8080-exec-9] s.s.w.c.SecurityContextPersistenceFilter : Cleared SecurityContextHolder to complete request这个过程中有两点比较重要：第一点是经过 AnonymousAuthenticationFilter 时，将当前用户设置为 anonymousUser，角色为 ROLE_ANONYMOUS；第二点是经过 FilterSecurityInterceptor 时，校验当前用户是否有访问 /hello 页面的权限，在上面的 defaultSecurityFilterChain 中，可以看到 http.authorizeRequests().anyRequest().authenticated() 这样的代码，这说明 Spring Security 默认对所有的页面都开启了鉴权，所以会抛出 AccessDeniedException 异常，而这个异常被 ExceptionTranslationFilter 拦截，并将这个异常交给 LoginUrlAuthenticationEntryPoint 处理，从而重定向到 /login 页面，整个过程的示意图如下：接下来，浏览器开始访问重定向后的 /login 页面，这时请求又会再一次经历一系列的 Security Filters，和上面的 /hello 请求不一样的是，/login 请求经过 DefaultLoginPageGeneratingFilter 时，会生成上面我们看到的登录页面并结束整个调用链：public class DefaultLoginPageGeneratingFilter extends GenericFilterBean { private void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException { boolean loginError = isErrorPage(request); boolean logoutSuccess = isLogoutSuccess(request); if (isLoginUrlRequest(request) || loginError || logoutSuccess) { String loginPageHtml = generateLoginPageHtml(request, loginError, logoutSuccess); response.setContentType("text/html;charset=UTF-8"); response.setContentLength(loginPageHtml.getBytes(StandardCharsets.UTF_8).length); response.getWriter().write(loginPageHtml); return; } chain.doFilter(request, response); } }AuthenticationManager：剖析认证流程接下来，输入用户名和密码并提交，请求会再一次经历 Security Filters，这一次，请求在 UsernamePasswordAuthenticationFilter 这里被拦截下来，并开始了用户名和密码的认证过程：public class UsernamePasswordAuthenticationFilter extends AbstractAuthenticationProcessingFilter { @Override public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException { if (this.postOnly && !request.getMethod().equals("POST")) { throw new AuthenticationServiceException("Authentication method not supported: " + request.getMethod()); } String username = obtainUsername(request); username = (username != null) ? username.trim() : ""; String password = obtainPassword(request); password = (password != null) ? password : ""; UsernamePasswordAuthenticationToken authRequest = UsernamePasswordAuthenticationToken.unauthenticated(username, password); // Allow subclasses to set the "details" property setDetails(request, authRequest); return this.getAuthenticationManager().authenticate(authRequest); } }这里将遇到 Spring Security 中处理认证的核心接口：AuthenticationManager：public interface AuthenticationManager { Authentication authenticate(Authentication authentication) throws AuthenticationException; }这个接口只有一个 authenticate() 方法，它的入参是一个未认证的 Authentication，从 UsernamePasswordAuthenticationFilter 的代码中可以看到使用了 UsernamePasswordAuthenticationToken，它的返回有三种情况：如果认证成功，则返回认证成功后的 Authentication（通常带有 authenticated=true）；如果认证失败，则抛出 AuthenticationException 异常；如果无法判断，则返回 null；AuthenticationManager 接口最常用的一个实现是 ProviderManager 类，它包含了一个或多个 AuthenticationProvider 实例：public class ProviderManager implements AuthenticationManager { private List<AuthenticationProvider> providers; }AuthenticationProvider 有点像 AuthenticationManager，但它有一个额外的方法 boolean supports(Class<?> authentication)：public interface AuthenticationProvider { Authentication authenticate(Authentication authentication) throws AuthenticationException; boolean supports(Class<?> authentication); }Spring Security 会遍历列表中所有的 AuthenticationProvider，并通过 supports() 方法来选取合适的 AuthenticationProvider 实例来实现认证，从上文中我们知道，UsernamePasswordAuthenticationFilter 在认证时使用的 Authentication 类型为 UsernamePasswordAuthenticationToken，对于这个 Authentication，默认使用的 AuthenticationProvider 是 DaoAuthenticationProvider，它继承自抽象类 AbstractUserDetailsAuthenticationProvider：public abstract class AbstractUserDetailsAuthenticationProvider implements AuthenticationProvider, InitializingBean, MessageSourceAware { @Override public Authentication authenticate(Authentication authentication) throws AuthenticationException { String username = determineUsername(authentication); UserDetails user = retrieveUser(username, (UsernamePasswordAuthenticationToken) authentication); this.preAuthenticationChecks.check(user); additionalAuthenticationChecks(user, (UsernamePasswordAuthenticationToken) authentication); this.postAuthenticationChecks.check(user); Object principalToReturn = user; if (this.forcePrincipalAsString) { principalToReturn = user.getUsername(); } return createSuccessAuthentication(principalToReturn, authentication, user); } }其中，最关键的代码有两行，第一行是通过 retrieveUser() 方法获取 UserDetails：public class DaoAuthenticationProvider extends AbstractUserDetailsAuthenticationProvider { @Override protected final UserDetails retrieveUser(String username, UsernamePasswordAuthenticationToken authentication) throws AuthenticationException { UserDetails loadedUser = this.getUserDetailsService().loadUserByUsername(username); return loadedUser; } }进入 retrieveUser() 方法内部，可以看到它是通过 UserDetailsService 的 loadUserByUsername() 方法来获取 UserDetails 的，而这个 UserDetailsService 默认实现是 InMemoryUserDetailsManager：public class InMemoryUserDetailsManager implements UserDetailsManager, UserDetailsPasswordService { @Override public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException { UserDetails user = this.users.get(username.toLowerCase()); if (user == null) { throw new UsernameNotFoundException(username); } return new User(user.getUsername(), user.getPassword(), user.isEnabled(), user.isAccountNonExpired(), user.isCredentialsNonExpired(), user.isAccountNonLocked(), user.getAuthorities()); } }它的实现非常简单，就是从 users 这个 Map 中直接获取 UserDetails，那么 users 这个 Map 又是从哪来的呢？ 答案就是我们在配置文件中配置的 spring.security.user，我们可以从自动配置类 UserDetailsServiceAutoConfiguration 中找到 InMemoryUserDetailsManager 的初始化代码：public class UserDetailsServiceAutoConfiguration { @Bean @Lazy public InMemoryUserDetailsManager inMemoryUserDetailsManager(SecurityProperties properties, ObjectProvider<PasswordEncoder> passwordEncoder) { SecurityProperties.User user = properties.getUser(); List<String> roles = user.getRoles(); return new InMemoryUserDetailsManager(User.withUsername(user.getName()) .password(getOrDeducePassword(user, passwordEncoder.getIfAvailable())) .roles(StringUtils.toStringArray(roles)) .build()); } }另一行关键代码是通过 additionalAuthenticationChecks() 方法对 UserDetails 和 UsernamePasswordAuthenticationToken 进行校验，一般来说，就是验证密码是否正确：public class DaoAuthenticationProvider extends AbstractUserDetailsAuthenticationProvider { @Override protected void additionalAuthenticationChecks(UserDetails userDetails, UsernamePasswordAuthenticationToken authentication) throws AuthenticationException { String presentedPassword = authentication.getCredentials().toString(); if (!this.passwordEncoder.matches(presentedPassword, userDetails.getPassword())) { this.logger.debug("Failed to authenticate since password does not match stored value"); throw new BadCredentialsException(this.messages .getMessage("AbstractUserDetailsAuthenticationProvider.badCredentials", "Bad credentials")); } } }一旦用户名和密码都验证通过，就调用 createSuccessAuthentication() 方法创建并返回一个认证成功后的 Authentication，然后经过一系列的后处理，整个认证的流程如下所示：其中，SecurityContextHolder 将认证成功后的 Authentication 保存到安全上下文中供后续 Filter 使用；AuthenticationSuccessHandler 用于定义一些认证成功后的自定义逻辑，默认实现为 SimpleUrlAuthenticationSuccessHandler，它返回一个重定向，将浏览器转到登录之前用户访问的页面。在我的测试中，SimpleUrlAuthenticationSuccessHandler 貌似并没有触发，新版本的逻辑有变动？AccessDecisionManager：剖析授权流程其实，在上面分析重定向 /login 页面的流程时已经大致了解了实现授权的逻辑，请求经过 FilterSecurityInterceptor 时，校验当前用户是否有访问页面的权限，如果没有，则会抛出 AccessDeniedException 异常。FilterSecurityInterceptor 的核心代码如下：public class FilterSecurityInterceptor extends AbstractSecurityInterceptor implements Filter { public void invoke(FilterInvocation filterInvocation) throws IOException, ServletException { InterceptorStatusToken token = super.beforeInvocation(filterInvocation); try { filterInvocation.getChain().doFilter(filterInvocation.getRequest(), filterInvocation.getResponse()); } finally { super.finallyInvocation(token); } super.afterInvocation(token, null); } }可以看到，主要逻辑就包含在 beforeInvocation()、finallyInvocation() 和 afterInvocation() 这三个方法中，而对授权相关的部分则位于 beforeInvocation() 方法中：public abstract class AbstractSecurityInterceptor implements InitializingBean, ApplicationEventPublisherAware, MessageSourceAware { protected InterceptorStatusToken beforeInvocation(Object object) { Collection<ConfigAttribute> attributes = this.obtainSecurityMetadataSource().getAttributes(object); Authentication authenticated = authenticateIfRequired(); // Attempt authorization attemptAuthorization(object, attributes, authenticated); if (this.publishAuthorizationSuccess) { publishEvent(new AuthorizedEvent(object, attributes, authenticated)); } return new InterceptorStatusToken(SecurityContextHolder.getContext(), false, attributes, object); } private void attemptAuthorization(Object object, Collection<ConfigAttribute> attributes, Authentication authenticated) { try { this.accessDecisionManager.decide(authenticated, object, attributes); } catch (AccessDeniedException ex) { publishEvent(new AuthorizationFailureEvent(object, attributes, authenticated, ex)); throw ex; } } }在这里，我们遇到了 Spring Security 实现授权的核心接口：AccessDecisionManager，Spring Security 就是通过该接口的 decide() 方法来决定用户是否有访问某个资源的权限。AccessDecisionManager 接口的默认实现为 AffirmativeBased，可以从 AbstractInterceptUrlConfigurer 中找到它的踪影：public abstract class AbstractInterceptUrlConfigurer<C extends AbstractInterceptUrlConfigurer<C, H>, H extends HttpSecurityBuilder<H>> extends AbstractHttpConfigurer<C, H> { private AccessDecisionManager createDefaultAccessDecisionManager(H http) { AffirmativeBased result = new AffirmativeBased(getDecisionVoters(http)); return postProcess(result); } }AffirmativeBased 实例中包含一个或多个 AccessDecisionVoter，它通过遍历所有的 AccessDecisionVoter 依次投票决定授权是否允许，只要有一个 AccessDecisionVoter 拒绝，则抛出 AccessDeniedException 异常：public class AffirmativeBased extends AbstractAccessDecisionManager { @Override @SuppressWarnings({ "rawtypes", "unchecked" }) public void decide(Authentication authentication, Object object, Collection<ConfigAttribute> configAttributes) throws AccessDeniedException { int deny = 0; for (AccessDecisionVoter voter : getDecisionVoters()) { int result = voter.vote(authentication, object, configAttributes); switch (result) { case AccessDecisionVoter.ACCESS_GRANTED: return; case AccessDecisionVoter.ACCESS_DENIED: deny++; break; default: break; } } if (deny > 0) { throw new AccessDeniedException( this.messages.getMessage("AbstractAccessDecisionManager.accessDenied", "Access is denied")); } // To get this far, every AccessDecisionVoter abstained checkAllowIfAllAbstainDecisions(); } }默认情况下，AffirmativeBased 实例中只有一个 AccessDecisionVoter，那就是 WebExpressionVoter：public class WebExpressionVoter implements AccessDecisionVoter<FilterInvocation> { @Override public int vote(Authentication authentication, FilterInvocation filterInvocation, Collection<ConfigAttribute> attributes) { WebExpressionConfigAttribute webExpressionConfigAttribute = findConfigAttribute(attributes); EvaluationContext ctx = webExpressionConfigAttribute.postProcess( this.expressionHandler.createEvaluationContext(authentication, filterInvocation), filterInvocation); boolean granted = ExpressionUtils.evaluateAsBoolean(webExpressionConfigAttribute.getAuthorizeExpression(), ctx); if (granted) { return ACCESS_GRANTED; } return ACCESS_DENIED; } }WebExpressionVoter 将授权转换为 SpEL 表达式，检查授权是否通过，就是看执行 SpEL 表达式的结果是否为 true，这里的细节还有很多，详细内容还是参考 官方文档 吧。参考Spring Security DocumentationGetting started with Spring Security and Spring BootSpring Security Tutorial 《Spring Security 教程》Spring Security 从入门到进阶Spring Security 认证流程Spring Security 鉴权流程更多Spring Security 的安全防护Protection Against ExploitsConfiguring CSRF/XSRF with Spring SecurityConfiguring CORS with Spring Boot and Spring SecuritySpring Security 自定义配置Java ConfigurationA Custom Spring SecurityConfigurerSpring Security 单元测试Testing
GitOps 这个概念最早是由 Weaveworks 的 CEO Alexis Richardson 在 2017 年提出的，它是一种全新的基于 Git 仓库来管理 Kubernetes 集群和交付应用程序的方式。它包含以下四个基本原则：声明式（Declarative）：整个系统必须通过声明式的方式进行描述，比如 Kubernetes 就是声明式的，它通过 YAML 来描述系统的期望状态；版本控制和不可变（Versioned and immutable）：所有的声明式描述都存储在 Git 仓库中，通过 Git 我们可以对系统的状态进行版本控制，记录了整个系统的修改历史，可以方便地回滚；自动拉取（Pulled automatically）：我们通过提交代码的形式将系统的期望状态提交到 Git 仓库，系统从 Git 仓库自动拉取并做出变更，这种被称为 Pull 模式，整个过程不需要安装额外的工具，也不需要配置 Kubernetes 的认证授权；而传统的 CI/CD 工具如 Jenkins 或 CircleCI 等使用的是 Push 模式，这种模式一般都会在 CI 流水线运行完成后通过执行命令将应用部署到系统中，这不仅需要安装额外工具（比如 kubectl），还需要配置 Kubernetes 的授权，而且这种方式无法感知部署状态，所以也就无法保证集群状态的一致性了；持续调谐（Continuously reconciled）：通过在目标系统中安装一个 Agent，一般使用 Kubernetes Operator 来实现，它会定期检测实际状态与期望状态是否一致，一旦检测到不一致，Agent 就会自动进行修复，确保系统达到期望状态，这个过程就是调谐（Reconciliation）；这样做的好处是将 Git 仓库作为单一事实来源，即使集群由于误操作被修改，Agent 也会通过持续调谐自动恢复。其实，在提出 GitOps 概念之前，已经有另一个概念 IaC （Infrastructure as Code，基础设施即代码）被提出了，IaC 表示使用代码来定义基础设施，方便编辑和分发系统配置，它作为 DevOps 的最佳实践之一得到了社区的广泛关注。关于 IaC 和 GitOps 的区别，可以参考 The GitOps FAQ。Argo CD 快速入门基于 GitOps 理念，很快诞生出了一批 声明式的持续交付（Declarative Continuous Deployment） 工具，比如 Weaveworks 的 Flux CD 和 Intuit 的 Argo CD，虽然 Weaveworks 是 GitOps 概念的提出者，但是从社区的反应来看，似乎 Argo CD 要更胜一筹。Argo 项目最初是由 Applatix 公司于 2017 年创建，2018 年这家公司被 Intuit 收购，Argo 项目就由 Intuit 继续维护和演进。Argo 目前包含了四个子项目：Argo Workflows、Argo Events、Argo CD 和 Argo Rollouts，主要用于运行和管理 Kubernetes 上的应用程序和任务，所有的 Argo 项目都是基于 Kubernetes 控制器和自定义资源实现的，它们组合在一起，提供了创建应用程序和任务的三种模式：服务模式、工作流模式和基于事件的模式。2020 年 4 月 7 日，Argo 项目加入 CNCF 开始孵化，并于 2022 年 12 月正式毕业，成为继 Kubernetes、Prometheus 和 Envoy 之后的又一个 CNCF 毕业项目。这一节我们将学习 Argo CD，学习如何通过 Git 以及声明式描述来部署 Kubernetes 资源。安装 Argo CDArgo CD 提供了两种 安装形式：多租户模式（Multi-Tenant） 和 核心模式（Core）。多租户模式提供了 Argo CD 的完整特性，包括 UI、SSO、多集群管理等，适用于多个团队用户共同使用；而核心模式只包含核心组件，不包含 UI 及多租户功能，适用于集群管理员独自使用。使用比较多的是多租户模式，官方还为其提供了两份部署配置：非高可用配置 install.yaml 和高可用配置 ha/install.yaml，生产环境建议使用高可用配置，开发和测试环境可以使用非高可用配置，下面就使用非高可用配置来安装 Argo CD。首先，创建一个 argocd 命名空间：$ kubectl create namespace argocd namespace/argocd created接着将 Argo CD 部署到该命名空间中：$ kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml customresourcedefinition.apiextensions.k8s.io/applications.argoproj.io created customresourcedefinition.apiextensions.k8s.io/applicationsets.argoproj.io created customresourcedefinition.apiextensions.k8s.io/appprojects.argoproj.io created serviceaccount/argocd-application-controller created serviceaccount/argocd-applicationset-controller created serviceaccount/argocd-dex-server created serviceaccount/argocd-notifications-controller created serviceaccount/argocd-redis created serviceaccount/argocd-repo-server created serviceaccount/argocd-server created role.rbac.authorization.k8s.io/argocd-application-controller created role.rbac.authorization.k8s.io/argocd-applicationset-controller created role.rbac.authorization.k8s.io/argocd-dex-server created role.rbac.authorization.k8s.io/argocd-notifications-controller created role.rbac.authorization.k8s.io/argocd-server created clusterrole.rbac.authorization.k8s.io/argocd-application-controller created clusterrole.rbac.authorization.k8s.io/argocd-server created rolebinding.rbac.authorization.k8s.io/argocd-application-controller created rolebinding.rbac.authorization.k8s.io/argocd-applicationset-controller created rolebinding.rbac.authorization.k8s.io/argocd-dex-server created rolebinding.rbac.authorization.k8s.io/argocd-notifications-controller created rolebinding.rbac.authorization.k8s.io/argocd-redis created rolebinding.rbac.authorization.k8s.io/argocd-server created clusterrolebinding.rbac.authorization.k8s.io/argocd-application-controller created clusterrolebinding.rbac.authorization.k8s.io/argocd-server created configmap/argocd-cm created configmap/argocd-cmd-params-cm created configmap/argocd-gpg-keys-cm created configmap/argocd-notifications-cm created configmap/argocd-rbac-cm created configmap/argocd-ssh-known-hosts-cm created configmap/argocd-tls-certs-cm created secret/argocd-notifications-secret created secret/argocd-secret created service/argocd-applicationset-controller created service/argocd-dex-server created service/argocd-metrics created service/argocd-notifications-controller-metrics created service/argocd-redis created service/argocd-repo-server created service/argocd-server created service/argocd-server-metrics created deployment.apps/argocd-applicationset-controller created deployment.apps/argocd-dex-server created deployment.apps/argocd-notifications-controller created deployment.apps/argocd-redis created deployment.apps/argocd-repo-server created deployment.apps/argocd-server created statefulset.apps/argocd-application-controller created networkpolicy.networking.k8s.io/argocd-application-controller-network-policy created networkpolicy.networking.k8s.io/argocd-applicationset-controller-network-policy created networkpolicy.networking.k8s.io/argocd-dex-server-network-policy created networkpolicy.networking.k8s.io/argocd-notifications-controller-network-policy created networkpolicy.networking.k8s.io/argocd-redis-network-policy created networkpolicy.networking.k8s.io/argocd-repo-server-network-policy created networkpolicy.networking.k8s.io/argocd-server-network-policy created另外，还可以通过 Helm 来部署 Argo CD，这里是社区维护的 Helm Charts。通过 Web UI 访问 Argo CDArgo CD 部署好之后，默认情况下，API Server 从集群外是无法访问的，这是因为 API Server 的服务类型是 ClusterIP：$ kubectl get svc argocd-server -n argocd NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE argocd-server ClusterIP 10.111.209.6 <none> 80/TCP,443/TCP 23h我们可以使用 kubectl patch 将其改为 NodePort 或 LoadBalancer：$ kubectl patch svc argocd-server -n argocd -p '{"spec": {"type": "NodePort"}}'修改之后，Kubernetes 会为 API Server 随机分配端口：$ kubectl get svc argocd-server -n argocd NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE argocd-server NodePort 10.111.209.6 <none> 80:32130/TCP,443:31205/TCP 23h这时我们就可以通过 localhost:32130 或 localhost:31205 来访问 API Server 了：可以看到 API Server 需要登录才能访问，初始用户名为 admin，初始密码在部署时随机生成，并保存在 argocd-initial-admin-secret 这个 Secret 里：$ kubectl get secrets argocd-initial-admin-secret -n argocd -o yaml apiVersion: v1 data: password: SlRyZDYtdEpOT1JGcXI3QQ== kind: Secret metadata: creationTimestamp: "2023-05-04T00:14:19Z" name: argocd-initial-admin-secret namespace: argocd resourceVersion: "17363" uid: 0cce4b4a-ff9d-44b3-930d-48bc5530bef0 type: Opaque密码以 BASE64 形式存储，可以使用下面的命令快速得到明文密码：$ kubectl get secrets argocd-initial-admin-secret -n argocd --template={{.data.password}} | base64 -d JTrd6-tJNORFqr7A输入用户名和密码登录成功后，进入 Argo CD 的应用管理页面：除了修改服务类型，官方还提供了两种方法暴露 API Server：一种是 使用 Ingress 网关，另一种是使用 kubectl port-forward 命令进行端口转发：$ kubectl port-forward svc argocd-server -n argocd 8080:443通过 CLI 访问 Argo CD我们也可以使用命令行客户端来访问 Argo CD，首先使用 curl 命令下载：$ curl -LO https://github.com/argoproj/argo-cd/releases/download/v2.7.1/argocd-linux-amd64然后使用 install 命令安装：$ sudo install -m 555 argocd-linux-amd64 /usr/local/bin/argocd使用 argocd version 查看 Argo CD 的版本信息，验证安装是否成功：$ argocd version argocd: v2.7.1+5e54351 BuildDate: 2023-05-02T16:54:25Z GitCommit: 5e543518dbdb5384fa61c938ce3e045b4c5be325 GitTreeState: clean GoVersion: go1.19.8 Compiler: gc Platform: linux/amd64 FATA[0000] Argo CD server address unspecified由于此时还没有配置服务端，所以 argocd version 只显示了 Argo CD 客户端的版本信息，没有服务端的版本信息。通过上一节的方法将 API Server 暴露之后，就可以使用 argocd login 连接服务端：$ argocd login localhost:32130 WARNING: server certificate had error: x509: certificate signed by unknown authority. Proceed insecurely (y/n)? y Username: admin Password: 'admin:login' logged in successfully Context 'localhost:32130' updated登录成功后，再次查看版本：$ argocd version argocd: v2.7.1+5e54351 BuildDate: 2023-05-02T16:54:25Z GitCommit: 5e543518dbdb5384fa61c938ce3e045b4c5be325 GitTreeState: clean GoVersion: go1.19.8 Compiler: gc Platform: linux/amd64 argocd-server: v2.7.1+5e54351.dirty BuildDate: 2023-05-02T16:35:40Z GitCommit: 5e543518dbdb5384fa61c938ce3e045b4c5be325 GitTreeState: dirty GoVersion: go1.19.6 Compiler: gc Platform: linux/amd64 Kustomize Version: v5.0.1 2023-03-14T01:32:48Z Helm Version: v3.11.2+g912ebc1 Kubectl Version: v0.24.2 Jsonnet Version: v0.19.1部署应用这一节我们将学习如何通过 Argo CD 来部署一个 Kubernetes 应用，官方在 argoproj/argocd-example-apps 仓库中提供了很多示例应用可供我们直接使用，这里我们将使用其中的 guestbook 应用。通过 Web UI 部署应用最简单的方法是通过 Argo CD 提供的可视化页面 Web UI 来部署应用，打开 Argo CD 的应用管理页面，点击 + NEW APP 按钮，弹出新建应用的对话框：对话框中的选项比较多，但是我们只需要填写红框部分的内容即可，包括：通用配置应用名称：guestbook项目名称：default同步策略：Manual源配置Git 仓库地址：https://github.com/argoproj/argocd-example-apps.git分支：HEAD代码路径：guestbook目标配置集群地址：https://kubernetes.default.svc命名空间：default其他的选项暂时可以不用管，如果想了解具体内容可以参考官方文档 Sync Options，填写完成后，点击 CREATE 按钮即可创建应用：因为刚刚填写的同步策略是手工同步，所以我们能看到应用的状态还是 OutOfSync，点击应用详情：可以看到 Argo CD 已经从 Git 仓库的代码中解析出应用所包含的 Kubernetes 资源了，guestbook 应用包含了一个 Deployment 和 一个 Service，点击 SYNC 按钮触发同步，Deployment 和 Service（以及它们关联的资源）被成功部署到 Kubernetes 集群中：测试完成后，点击 DELETE 删除应用，该应用关联的资源将会被级联删除。通过 CLI 部署应用我们还可以通过 Argo CD 提供的命令行工具来部署应用，经过上一节的步骤，我们已经登录了 API Server，我们只需要执行下面的 argocd app create 命令即可创建 guestbook 应用：$ argocd app create guestbook \ --repo https://github.com/argoproj/argocd-example-apps.git \ --path guestbook \ --dest-server https://kubernetes.default.svc \ --dest-namespace default application 'guestbook' created也可以使用 YAML 文件声明式地创建 Argo CD 应用：apiVersion: argoproj.io/v1alpha1 kind: Application metadata: name: guestbook namespace: argocd spec: project: default source: repoURL: https://github.com/argoproj/argocd-example-apps.git targetRevision: HEAD path: guestbook destination: server: https://kubernetes.default.svc namespace: guestbook我们创建一个 YAML 文件，包含以上内容，然后执行 kubectl apply -f 即可，和 Web UI 操作类似，刚创建的应用处于 OutOfSync 状态，我们可以使用 argocd app get 命令查询应用详情进行确认：$ argocd app get guestbook Name: argocd/guestbook Project: default Server: https://kubernetes.default.svc Namespace: default URL: https://localhost:32130/applications/guestbook Repo: https://github.com/argoproj/argocd-example-apps.git Target: Path: guestbook SyncWindow: Sync Allowed Sync Policy: <none> Sync Status: OutOfSync from (53e28ff) Health Status: Missing GROUP KIND NAMESPACE NAME STATUS HEALTH HOOK MESSAGE Service default guestbook-ui OutOfSync Missing apps Deployment default guestbook-ui OutOfSync Missing接着我们执行 argocd app sync 命令，手工触发同步：$ argocd app sync guestbook TIMESTAMP GROUP KIND NAMESPACE NAME STATUS HEALTH HOOK MESSAGE 2023-05-06T08:22:53+08:00 Service default guestbook-ui OutOfSync Missing 2023-05-06T08:22:53+08:00 apps Deployment default guestbook-ui OutOfSync Missing 2023-05-06T08:22:53+08:00 Service default guestbook-ui Synced Healthy 2023-05-06T08:22:54+08:00 Service default guestbook-ui Synced Healthy service/guestbook-ui created 2023-05-06T08:22:54+08:00 apps Deployment default guestbook-ui OutOfSync Missing deployment.apps/guestbook-ui created 2023-05-06T08:22:54+08:00 apps Deployment default guestbook-ui Synced Progressing deployment.apps/guestbook-ui created Name: argocd/guestbook Project: default Server: https://kubernetes.default.svc Namespace: default URL: https://localhost:32130/applications/guestbook Repo: https://github.com/argoproj/argocd-example-apps.git Target: Path: guestbook SyncWindow: Sync Allowed Sync Policy: <none> Sync Status: Synced to (53e28ff) Health Status: Progressing Operation: Sync Sync Revision: 53e28ff20cc530b9ada2173fbbd64d48338583ba Phase: Succeeded Start: 2023-05-06 08:22:53 +0800 CST Finished: 2023-05-06 08:22:54 +0800 CST Duration: 1s Message: successfully synced (all tasks run) GROUP KIND NAMESPACE NAME STATUS HEALTH HOOK MESSAGE Service default guestbook-ui Synced Healthy service/guestbook-ui created apps Deployment default guestbook-ui Synced Progressing deployment.apps/guestbook-ui created等待一段时间后，应用关联资源就部署完成了：$ kubectl get all NAME READY STATUS RESTARTS AGE pod/guestbook-ui-b848d5d9d-rtzwf 1/1 Running 0 67s NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/guestbook-ui ClusterIP 10.107.51.212 <none> 80/TCP 67s service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 30d NAME READY UP-TO-DATE AVAILABLE AGE deployment.apps/guestbook-ui 1/1 1 1 67s NAME DESIRED CURRENT READY AGE replicaset.apps/guestbook-ui-b848d5d9d 1 1 1 67s测试完成后，执行 argocd app delete 命令删除应用，该应用关联的资源将会被级联删除：$ argocd app delete guestbook Are you sure you want to delete 'guestbook' and all its resources? [y/n] y application 'guestbook' deleted参考Argo CD Getting StartedGitOps 介绍Argo CD 入门教程GitOps 应用实践系列 - 综述GitOps 应用实践系列 - Argo CD 的基本介绍Guide To GitOpsThe GitOps FAQWhat Is GitOpsThe History of GitOpsCNCF 宣布 Argo 正式毕业更多部署其他的应用类型Argo CD 不仅支持原生的 Kubernetes 配置清单，也支持 Helm Chart、Kustomize 或者 Jsonnet 部署清单，甚至可以通过 Config Management Plugins 实现自定义配置。Flux CDGitOps 应用实践系列 - Flux CD 及其核心组件Argo CD vs Flux CD — Right GitOps tool for your Kubernetes cluster