This project provides an API Gateway built on top of the Spring Ecosystem, including: Spring 5, Spring Boot 2 and Project Reactor. Spring Cloud Gateway aims to provide a simple, yet effective way to route to APIs and provide cross cutting concerns to them such as: security, monitoring/metrics, and resiliency.

Features

• Java 8

• Spring Framework 5

• Spring Boot 2

• Dynamic routing

• Route matching built into Spring Handler Mapping

• Route matching on HTTP Request (Path, Method, Header, Host, etc…​)

• Filters scoped to Matching Route

• Filters can modify downstream HTTP Request and HTTP Response (Add/Remove Headers, Add/Remove Parameters, Rewrite Path, Set Path, Hystrix, etc…​)

• API or configuration driven

• Supports Spring Cloud DiscoveryClient for configuring Routes

Building

Basic Compile and Test

To build the source you will need to install JDK 1.8.

Spring Cloud uses Maven for most build-related activities, and you should be able to get off the ground quite quickly by cloning the project you are interested in and typing

$ ./mvnw install

Note	You can also install Maven (>=3.3.3) yourself and run the mvn command in place of ./mvnw in the examples below. If you do that you also might need to add -P spring if your local Maven settings do not contain repository declarations for spring pre-release artifacts.

Note

Be aware that you might need to increase the amount of memory available to Maven by setting a MAVEN_OPTS environment variable with a value like -Xmx512m -XX:MaxPermSize=128m. We try to cover this in the .mvn configuration, so if you find you have to do it to make a build succeed, please raise a ticket to get the settings added to source control.

The projects that require middleware (i.e. Redis) for testing generally require that a local instance of [Docker](https://www.docker.com/get-started) is installed and running.

Documentation

The spring-cloud-build module has a "docs" profile, and if you switch that on it will try to build asciidoc sources from src/main/asciidoc. As part of that process it will look for a README.adoc and process it by loading all the includes, but not parsing or rendering it, just copying it to ${main.basedir} (defaults to ${basedir}, i.e. the root of the project). If there are any changes in the README it will then show up after a Maven build as a modified file in the correct place. Just commit it and push the change.

Working with the code

If you don’t have an IDE preference we would recommend that you use Spring Tools Suite or Eclipse when working with the code. We use the m2eclipse eclipse plugin for maven support. Other IDEs and tools should also work without issue as long as they use Maven 3.3.3 or better.

Activate the Spring Maven profile

Spring Cloud projects require the 'spring' Maven profile to be activated to resolve the spring milestone and snapshot repositories. Use your preferred IDE to set this profile to be active, or you may experience build errors.

Importing into eclipse with m2eclipse

We recommend the m2eclipse eclipse plugin when working with eclipse. If you don’t already have m2eclipse installed it is available from the "eclipse marketplace".

Note

Older versions of m2e do not support Maven 3.3, so once the projects are imported into Eclipse you will also need to tell m2eclipse to use the right profile for the projects. If you see many different errors related to the POMs in the projects, check that you have an up to date installation. If you can’t upgrade m2e, add the "spring" profile to your settings.xml. Alternatively you can copy the repository settings from the "spring" profile of the parent pom into your settings.xml.

Importing into eclipse without m2eclipse

If you prefer not to use m2eclipse you can generate eclipse project metadata using the following command:

$ ./mvnw eclipse:eclipse

The generated eclipse projects can be imported by selecting import existing projects from the file menu.

Contributing

Spring Cloud is released under the non-restrictive Apache 2.0 license, and follows a very standard Github development process, using Github tracker for issues and merging pull requests into master. If you want to contribute even something trivial please do not hesitate, but follow the guidelines below.

Sign the Contributor License Agreement

Before we accept a non-trivial patch or pull request we will need you to sign the Contributor License Agreement. Signing the contributor’s agreement does not grant anyone commit rights to the main repository, but it does mean that we can accept your contributions, and you will get an author credit if we do. Active contributors might be asked to join the core team, and given the ability to merge pull requests.

Code of Conduct

This project adheres to the Contributor Covenant code of conduct. By participating, you are expected to uphold this code. Please report unacceptable behavior to spring-code-of-conduct@pivotal.io.

Code Conventions and Housekeeping

None of these is essential for a pull request, but they will all help. They can also be added after the original pull request but before a merge.

• Use the Spring Framework code format conventions. If you use Eclipse you can import formatter settings using the eclipse-code-formatter.xml file from the Spring Cloud Build project. If using IntelliJ, you can use the Eclipse Code Formatter Plugin to import the same file.

• Make sure all new .java files to have a simple Javadoc class comment with at least an @author tag identifying you, and preferably at least a paragraph on what the class is for.

• Add the ASF license header comment to all new .java files (copy from existing files in the project)

• Add yourself as an @author to the .java files that you modify substantially (more than cosmetic changes).

• Add some Javadocs and, if you change the namespace, some XSD doc elements.

• A few unit tests would help a lot as well — someone has to do it.

• If no-one else is using your branch, please rebase it against the current master (or other target branch in the main project).

• When writing a commit message please follow these conventions, if you are fixing an existing issue please add Fixes gh-XXXX at the end of the commit message (where XXXX is the issue number).

Checkstyle

Spring Cloud Build comes with a set of checkstyle rules. You can find them in the spring-cloud-build-tools module. The most notable files under the module are:

spring-cloud-build-tools/

└── src
    ├── checkstyle
    │   └── checkstyle-suppressions.xml (3)
    └── main
        └── resources
            ├── checkstyle-header.txt (2)
            └── checkstyle.xml (1)

1. Default Checkstyle rules

2. File header setup

3. Default suppression rules

Checkstyle configuration

Checkstyle rules are disabled by default. To add checkstyle to your project just define the following properties and plugins.

pom.xml

<properties>
<maven-checkstyle-plugin.failsOnError>true</maven-checkstyle-plugin.failsOnError> (1)
        <maven-checkstyle-plugin.failsOnViolation>true
        </maven-checkstyle-plugin.failsOnViolation> (2)
        <maven-checkstyle-plugin.includeTestSourceDirectory>true
        </maven-checkstyle-plugin.includeTestSourceDirectory> (3)
</properties>

<build>
        <plugins>
            <plugin> (4)
                <groupId>io.spring.javaformat</groupId>
                <artifactId>spring-javaformat-maven-plugin</artifactId>
            </plugin>
            <plugin> (5)
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-checkstyle-plugin</artifactId>
            </plugin>
        </plugins>

    <reporting>
        <plugins>
            <plugin> (5)
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-checkstyle-plugin</artifactId>
            </plugin>
        </plugins>
    </reporting>
</build>

1. Fails the build upon Checkstyle errors

2. Fails the build upon Checkstyle violations

3. Checkstyle analyzes also the test sources

4. Add the Spring Java Format plugin that will reformat your code to pass most of the Checkstyle formatting rules

5. Add checkstyle plugin to your build and reporting phases

If you need to suppress some rules (e.g. line length needs to be longer), then it’s enough for you to define a file under ${project.root}/src/checkstyle/checkstyle-suppressions.xml with your suppressions. Example:

projectRoot/src/checkstyle/checkstyle-suppresions.xml

<?xml version="1.0"?>
<!DOCTYPE suppressions PUBLIC
		"-//Puppy Crawl//DTD Suppressions 1.1//EN"
		"https://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
<suppressions>
	<suppress files=".*ConfigServerApplication\.java" checks="HideUtilityClassConstructor"/>
	<suppress files=".*ConfigClientWatch\.java" checks="LineLengthCheck"/>
</suppressions>

It’s advisable to copy the ${spring-cloud-build.rootFolder}/.editorconfig and ${spring-cloud-build.rootFolder}/.springformat to your project. That way, some default formatting rules will be applied. You can do so by running this script:

$ curl https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/.editorconfig -o .editorconfig
$ touch .springformat

IDE setup

Intellij IDEA

In order to setup Intellij you should import our coding conventions, inspection profiles and set up the checkstyle plugin. The following files can be found in the Spring Cloud Build project.

spring-cloud-build-tools/

└── src
    ├── checkstyle
    │   └── checkstyle-suppressions.xml (3)
    └── main
        └── resources
            ├── checkstyle-header.txt (2)
            ├── checkstyle.xml (1)
            └── intellij
                ├── Intellij_Project_Defaults.xml (4)
                └── Intellij_Spring_Boot_Java_Conventions.xml (5)

1. Default Checkstyle rules

2. File header setup

3. Default suppression rules

4. Project defaults for Intellij that apply most of Checkstyle rules

5. Project style conventions for Intellij that apply most of Checkstyle rules

Figure 1. Code style

Go to File → Settings → Editor → Code style. There click on the icon next to the Scheme section. There, click on the Import Scheme value and pick the Intellij IDEA code style XML option. Import the spring-cloud-build-tools/src/main/resources/intellij/Intellij_Spring_Boot_Java_Conventions.xml file.

Figure 2. Inspection profiles

Go to File → Settings → Editor → Inspections. There click on the icon next to the Profile section. There, click on the Import Profile and import the spring-cloud-build-tools/src/main/resources/intellij/Intellij_Project_Defaults.xml file.

Checkstyle

To have Intellij work with Checkstyle, you have to install the Checkstyle plugin. It’s advisable to also install the Assertions2Assertj to automatically convert the JUnit assertions

Go to File → Settings → Other settings → Checkstyle. There click on the + icon in the Configuration file section. There, you’ll have to define where the checkstyle rules should be picked from. In the image above, we’ve picked the rules from the cloned Spring Cloud Build repository. However, you can point to the Spring Cloud Build’s GitHub repository (e.g. for the checkstyle.xml : https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/main/resources/checkstyle.xml). We need to provide the following variables:

• checkstyle.header.file - please point it to the Spring Cloud Build’s, spring-cloud-build-tools/src/main/resources/checkstyle-header.txt file either in your cloned repo or via the https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/main/resources/checkstyle-header.txt URL.

• checkstyle.suppressions.file - default suppressions. Please point it to the Spring Cloud Build’s, spring-cloud-build-tools/src/checkstyle/checkstyle-suppressions.xml file either in your cloned repo or via the https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/checkstyle/checkstyle-suppressions.xml URL.

• checkstyle.additional.suppressions.file - this variable corresponds to suppressions in your local project. E.g. you’re working on spring-cloud-contract. Then point to the project-root/src/checkstyle/checkstyle-suppressions.xml folder. Example for spring-cloud-contract would be: /home/username/spring-cloud-contract/src/checkstyle/checkstyle-suppressions.xml.

Important

Remember to set the Scan Scope to All sources since we apply checkstyle rules for production and test sources.

请求→Predicate→Route(匹配)→Filter(做过滤) 网关的核心功能时路由转发，因此不要有耗时操作在网关上处理，让请求快速转发到后端服务上 网关可以做统一的熔断、限流、认证、日志监控等 客户端向Spring Cloud Gateway发出请求，然后在Gateway Handler Mapping中找到与请求相匹配的路由，将其发送到Gateway Web Handler Handler再通过指定的过滤器链来将请求发送到我们实际的服务执行业务逻辑，然后返回，

路由：有ID、目标URI、断言集合、过滤器集合组成

断言：允许开发人员匹配HTTP请求中的任何内容，比如请求头或请求参数，最后根据匹配结果返回一个布尔值 内置了许多Predict，这些Predict的源码在org.springframework.cloud.gateway.handler.predict包中 - path=/api-boot-datasource-switch.html 在上面的配置中，当访问http://localhost:9090/api-boot-datasource-switch.html时就会被自动转发到http://blog.xx.com/api-boot-datasource-switch.html，这里要注意完全匹配Path的值时才会进行路由转发 - Before=2019-05-01T00:00:00+08:00[Asia/Shanghai] 在上面的配置中，我们允许2019-05-01日凌晨之前请求允许转发 -After=2019-04-29T00:00:00+08:00[Asia/Shanghai] 在上面配置中允许2019-04-29凌晨之后请求允许转发 - Between=2019-04-29T00:00:00+08:00[Asia/Shanghai], 2019-05-01T00:00:00+08:00[Asia/Shanghai] 在上面配置中，允许在2019-04-29日凌晨后 & 2019-05-01凌晨之前请求允许转发 - Cookie=hengboy, leo 在上面配置中，如果客户端发送请求时携带了"hengboy=leo"的Cookie信息，则允许请求转发；提供了根据Cookie值的方式匹配转发请求 - Header=X-Request-Id, \d+ 在上面配置中，如果X-Request-Id的值为数字，则允许请求转发；可以根据发送请求的Header信息进行匹配转发 - Host=*\*.xx.com 在上面配置中，如果客户端发送请求是*\*.xx.com域名，则允许请求转发；可以根据Host主机名进行匹配转发 - Method=POST 在上面配置中，如果客户端发送请求是POST请求，则允许请求转发 - Query=xxx 在上面配置中，如果客户端发送请求时携带"xxx"的参数信息，则允许请求转发；可以根据指定参数进行匹配转发 - Query=xxx, zzz 在上面配置中，如果客户端发送请求时携带"xxx=zzz"的参数信息，则允许请求转发 - Path=/article/{articleId} 在上面配置中，如果客户端发送请求路径是/article/1、/article/abc，则允许请求转发，如果客户端发送请求路径是/article/1/1，则不允许请求转发 - RemoteAddr=192.168.1.56/24 在上面配置中，如果客户端发送请求时客户端IP地址是192.168.1.56，则允许请求转发；可以限制允许访问接口的客户端IP地址，配置后只对指定IP的客户端进行请求转发

过滤器：可以在返回请求之前或之后修改请求和响应的内容 生命周期： PRE：这种过滤器在请求被路由之前调用。我们可利用这种过滤器实现身份验证、在集群中选择请求的微服务、记录调试信息 POST：这种过滤器在路由到微服务以后执行，这种过滤器可用来响应添加标准的HTTP Header、收集统计信息和指标、将响应从微服务发送给客户端等 过滤器从作用范围可分为两种： GatewayFilter：应用到单个路由或者一个分组路由上，内置了许多局部过滤器，局部过滤器需要在指定路由配置才能生效 GlobalFilter：应用到所有路由上，内置了许多全局过滤器，功能和GatewayFilter相同，只是GlobalFilter作用域是所有路由配置，而不是在指定的路由配置上 过滤器规则： PrefixPath - PrefixPath=/app 在请求路径前加上app RewritePath - RewritePath=/test, /app/test 访问localhost:9022/test,请求会转发到localhost:8001/app/test SetPath SetPath=/app/{path} 通过模板设置路径，转发的规则会在路径前增加app，{path}表示原请求路径 RedirectTo 重定向 RemoveRequestHeader 去掉某个请求头信息