If there are #{@myRateLimiter} is a SpEL expression that references a bean with named myRateLimiter. name can contain a space-separated list of header names. The following example configures an AddRequestParameter GatewayFilter: This will add red=blue to the downstream requests query string for all matching requests. 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. The collection of filters applied to the route. The headers with the exception type, message and (if available) root cause exception type and message are added to that request by the FallbackHeaders filter. Overview. Features. a circuit breaker. Creating of individual headers can be controlled by the following boolean properties (defaults to true): spring.cloud.gateway.x-forwarded.for-enabled, spring.cloud.gateway.x-forwarded.host-enabled, spring.cloud.gateway.x-forwarded.port-enabled, spring.cloud.gateway.x-forwarded.proto-enabled, spring.cloud.gateway.x-forwarded.prefix-enabled. A Gateway built on Spring Framework and Spring Boot providing routing and more. This predicate extracts the URI template variables (such as sub, defined in the preceding example) as a map of names and values and places it in the ServerWebExchange.getAttributes() with a key defined in ServerWebExchangeUtils.URI_TEMPLATE_VARIABLES_ATTRIBUTE. Spring Cloud - Cloud Foundry Service Broker. The global CORS configuration is a map of URL patterns to Spring Framework CorsConfiguration. m2eclipse to use the right profile for the projects. This interface and its usage are subject to change in future milestone releases. Also important is the fact that this configuration is a ModifyResponseBodyGatewayFilterFactory one. httpMethod: The HTTP method used for the request. This may not match the actual client IP address if Spring Cloud Gateway sits behind a proxy layer. If the URL located in the ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR exchange attribute has a ws or wss scheme, the websocket routing filter runs. TLS / SSL. Writing Custom GatewayFilter Factories, 17.2.1. The arguments are typically listed in the order that would be needed for the shortcut configuration. In this tutorial, we'll explore the main features of the Spring Cloud Gateway project, a new API based on Spring 5, Spring Boot 2 and Project Reactor. In our case, we only need two configuration properties: The key method we must implement is apply(). The RequestRateLimiter is not configurable with the "shortcut" notation. The SecureHeaders GatewayFilter factory adds a number of headers to the response, per the recommendation made in this blog post. To change this, set the spring.cloud.gateway.filter.remove-non-proxy-headers.headers property to the list of header names to remove. To retrieve information about a single route, make a GET request to /actuator/gateway/routes/{id} (for example, /actuator/gateway/routes/first_route). When communicating over HTTPS, the client initiates a TLS handshake. any changes in the README it will then show up after a Maven build as checkstyle.suppressions.file - default suppressions. Are you sure you want to create this branch? This predicate matches requests that happen before the specified datetime. Spring Cloud CircuitBreaker supports multiple libraries that can be used with Spring Cloud Gateway. You can extend an abstract class called AbstractGatewayFilterFactory. The default is 'B' for bytes. HttpHeadersFilters are applied to requests before sending them downstream, such as in the NettyRoutingFilter. This is equivalent to building a route using configuration properties but allows us to have full control of all aspects of the test route: Finally, with those beans now part of a @TestConfiguration, we can inject them into the actual test, together with a WebTestClient. should be able to get off the ground quite quickly by cloning the The stripVersionMode parameter has the following possible values: NEVER_STRIP, AS_IN_REQUEST (default), and ALWAYS_STRIP. This project provides a library for building an API Gateway on top of Spring WebFlux. Route matching built into Spring Handler Mapping, Route matching on HTTP Request (Path, Method, Header, Host, etc), Filters can modify downstream HTTP Request and HTTP Response (Add/Remove Headers, Add/Remove Parameters, Rewrite Path, Set Path, Hystrix, etc), Supports Spring Cloud DiscoveryClient for configuring Routes. Spring Cloud projects require the 'spring' Maven profile to be activated to resolve Secondly, we programmatically create a route @Bean that includes our filter. The following listing shows how to modify a request body GatewayFilter: You can use the ModifyResponseBody filter to modify the response body before it is sent back to the client. Spring Cloud Gateway consists of 3 main building blocks: Route: Think of this as the destination that we want a particular request to route to. If the URI has a scheme prefix, such as lb:ws://serviceid, the lb scheme is stripped from the URI and placed in the ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR for use later in the filter chain. in the project). It consists of the following building blocks-. For example, you might want to extract the trailing elements of a path to pass them downstream: All the features of Spring MVC and Webflux are available to gateway handler methods. If you use Eclipse Bootstrap your application with Spring Initializr. The default predicate is a path predicate defined with the pattern /serviceId/**, where serviceId is It must be a Java System Property, not a Spring Boot property. If you cant upgrade m2e, This predicates matches the Host header that matches the pattern. In our case, were not converting types, so both input and output use the same class: JsonNode. Duplicate finder is enabled by default and will run in the verify phase of your Maven build, but it will only take effect in your project if you add the duplicate-finder-maven-plugin to the build section of the projecsts pom.xml. In addition, you can configure this filter once by using spring.cloud.gateway.default-filters and have it applied to all routes. After the gateway has routed a ServerWebExchange, it marks that exchange as routed by adding gatewayAlreadyRouted Fails the build upon Checkstyle violations, Checkstyle analyzes also the test sources, Add the Spring Java Format plugin that will reformat your code to pass most of the Checkstyle formatting rules, Add checkstyle plugin to your build and reporting phases. It creates a new URI, based off of the request URI but updated with the URI attribute of the Route object. To allow for simple configuration in Java, the RouteLocatorBuilder bean includes a fluent API. Spring Cloud Gateway Architecture. README.adoc and process it by loading all the includes, but not When doing so, you need to make sure to include the default predicate and filter shown earlier, if you want to retain that functionality. So, as long we dont do any kind of blocking I/O operation, we can do some complex work inside the rewrite function. Spring Cloud Gateway relies on the Netty based runtime environment provided by Spring Boot and Spring WebFlux, it is not built as a WAR package or run in a traditional Servlet container. The following listing shows the definition of the RouteDefinitionLocator interface: By default, a PropertiesRouteDefinitionLocator loads properties by using Spring Boots @ConfigurationProperties mechanism. type away in either server and client, messages will be passed appropriately. The following listing configures a ReactiveLoadBalancerClientFilter: The Netty routing filter runs if the URL located in the ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR exchange attribute has a http or https scheme. The unmodified original URL is appended to the list in the ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR attribute. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. The previous sample defines the Cookie Route Predicate Factory with two arguments, the cookie name, mycookie and the value to match mycookievalue. For more information on circuit breakers and the gateway see the Spring Cloud CircuitBreaker Factory section. Spring Cloud Gateway comes with one non-default remote address resolver that is based off of the X-Forwarded-For header, XForwardedRemoteAddressResolver. This strips the service ID from the path before the request is sent downstream. The RewriteResponseHeader GatewayFilter factory takes name, regexp, and replacement parameters. The status parameter should be a 300 series redirect HTTP code, such as 301. if you are fixing an existing issue please add Fixes gh-XXXX at the end of the commit The following listing configures a websocket routing filter: To enable gateway metrics, add spring-boot-starter-actuator as a project dependency. The first is just a regular JUnit test used as a sanity check for the scrubber. Each item defines the name and the arguments of a given predicate. To enable the Spring Cloud CircuitBreaker filter, you need to place spring-cloud-starter-circuitbreaker-reactor-resilience4j on the classpath. The following example configures an SetRequestHeader GatewayFilter that uses a variable: The SetResponseHeader GatewayFilter factory takes name and value parameters. It runs after all other filters have completed and writes the proxy response back to the gateway client response. It consists of ID destination URI Collection of predicates and a collection of filters A route is matched if aggregate predicate is true. You can also manipulate response headers (and anything else you like in the response) by adding a mapper to the get() method (and other methods). The following describes an alternative style gateway. Spring Cloud Gateway 2.2.9.RELEASE This project provides an API Gateway built on top of the Spring Ecosystem, including: Spring 5, Spring Boot 2 and Project Reactor. The PreserveHostHeader GatewayFilter factory has no parameters. you can import formatter settings using the It offers a simple way to manipulate the request path by allowing templated segments of the path. The key point here is to use the apply() method variant that, instead of taking a configuration object, expects a Consumer for the configuration. Gateway routes can be routed to both http and https backends. As Spring Cloud Gateway distinguishes between pre and post phases for filter logic execution (see How it Works), the filter with the highest precedence is the first in the pre-phase and the last in the post-phase. First-class support is provided for sensitive headers (by default, cookie and authorization), which are not passed downstream, and for proxy (x-forwarded-*) headers. The following listing defines a rate limiter that uses the KeyResolver defined in the previous listing: The RedirectTo GatewayFilter factory takes two parameters, status and url. These are special filters that are conditionally applied to all routes. This class comes from the Jackson library and is at the very top of the hierarchy of classes used to represent different node types in JSON, such as object nodes, array nodes, and so forth. URIs defined in routes without a port get default port values of 80 and 443 for the HTTP and HTTPS URIs, respectively. In case of the request being forwarded to fallback, the Spring Cloud CircuitBreaker Gateway filter also provides the Throwable that has caused it. In order to write a Route Predicate you will need to implement RoutePredicateFactory. You can configure the SetStatus GatewayFilter to return the original HTTP status code from the proxied request in a header in the response. The filter takes a maxSize parameter. To better illustrate how response body manipulation works, lets create a simple filter that masks values in a JSON-based response. Spring Runtime offers support and binaries for OpenJDK, Spring, and Apache Tomcat in one simple subscription. It is the name of the header to be removed. Spring Cloud Gateway handles cross-cutting concerns for API development teams, such as single sign-on (SSO), access control, rate-limiting, resiliency, security, and more. We'll also configure the routing to access the greeting service: The accepted values are RETAIN_FIRST (default), RETAIN_LAST, and RETAIN_UNIQUE. All pre filter logic is executed. Introduction. Most examples below use the shortcut way. Predicate These are the set of criteria which should match for the incoming . If the new named header already exists, its values are augmented with the new values. Those values are then available for use by GatewayFilter factories. 2023 VMware, Inc. or its affiliates. By using the fluent Java API, you can use the and(), or(), and negate() operators on the Predicate class. AS_IN_REQUEST The version is stripped only if the original request path contains no version. Were also instructing the server to create a new default Executor to manage threads used to handle requests. There, youll have to define where the checkstyle rules should be picked from. Spring Cloud Gateway is an API Gateway / Backend For the FrontEnd (BFF) framework. Spring cloud gateway provides a library for building gateway API on top of java and spring. setting replenishRate=1, requestedTokens=60 and burstCapacity=60 will result in a limit of 1 request/min. The redis-rate-limiter.burstCapacity property is the maximum number of requests a user is allowed to do in a single second. spring: cloud: gateway: httpclient: ssl . The Path Route Predicate Factory takes two parameters: a list of Spring PathMatcher patterns and an optional flag called matchOptionalTrailingSeparator. A tag already exists with the provided branch name. It requires the use of the spring-boot-starter-data-redis-reactive Spring Boot starter. As filters are a core concept in SCG, all we need to do to support response processing is to implement a custom one that applies the desired transformation. The following listing configures a RewritePath GatewayFilter: For a request path of /red/blue, this sets the path to /blue before making the downstream request. VMware Spring Cloud Gateway is a commercial VMware Tanzu component based on the open-source Spring Cloud Gateway project. Spring Cloud Gateway includes many built-in route predicate factories. If Spring Cloud Gateway is, for example only accessible through HAProxy, then a value of 1 should be used. Spring Cloud Build brings along the basepom:duplicate-finder-maven-plugin, that enables flagging duplicate and conflicting classes and resources on the java classpath. Spring Cloud Gateway features: Built on Spring Framework 5, Project Reactor and Spring Boot 2.0. 1. If it is not, a status of HTTP 429 - Too Many Requests (by default) is returned. The LoadBalancerClientFilter looks for a URI in the exchange attribute named ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR. It uses Java regular expressions for a flexible way to rewrite the response header value. It adds the Host header, scheme and port of the current request to any existing Forwarded header. outcome: The outcome, as classified by HttpStatus.Series. You can adjust this behavior by setting the spring.cloud.gateway.filter.request-rate-limiter.deny-empty-key (true or false) and spring.cloud.gateway.filter.request-rate-limiter.empty-key-status-code properties. Please report It is added to the ServerWebExchange as the ServerWebExchangeUtils.CIRCUITBREAKER_EXECUTION_EXCEPTION_ATTR attribute that can be used when handling the fallback within the gateway application. The following example configures an AddRequestHeader GatewayFilter: This listing adds X-Request-red:blue header to the downstream requests headers for all matching requests. Learn more. regexp, so green and greet would match. The url parameter should be a valid URL. Cloud Build project. The following listing configures a Retry GatewayFilter: When the request size is greater than the permissible limit, the RequestSize GatewayFilter factory can restrict a request from reaching the downstream service. It is defined by an ID, a target URI, a collection of predicates (Predicate) and a collection . Those are . from the file menu. The Between route predicate factory takes two parameters, datetime1 and datetime2 The input type is a Spring Framework ServerWebExchange. The following example configures a method route predicate: This route matches if the request method was a GET or a POST. If it is not provided, the value of the Host request header is used. The following example configures an AddResponseHeader GatewayFilter: This adds X-Response-Foo:Bar header to the downstream responses headers for all matching requests. Spring Cloud Gateway matches routes as part of the Spring WebFlux HandlerMapping infrastructure. For the external controller/handler scenario, headers can be added with exception details. For a production deployment, you can configure the gateway with a set of known certificates that it can trust with the following configuration: If the Spring Cloud Gateway is not provisioned with trusted certificates, the default trust store is used (which you can override by setting the javax.net.ssl.trustStore system property). In the image above, weve picked the rules from the cloned Spring Cloud Build repository. The After route predicate factory takes one parameter, a datetime (which is a java ZonedDateTime). In future milestone releases, there will be some KeyResolver implementations. The primary scenario is to use the fallbackUri to define an internal controller or handler within the gateway application. The Cookie route predicate factory takes two parameters, the cookie name and a regexp (which is a Java regular expression). We need to provide the following variables: checkstyle.header.file - please point it to the Spring Cloud Builds, 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. The following example configures a PreserveHostHeader GatewayFilter: The RequestRateLimiter GatewayFilter factory uses a RateLimiter implementation to determine if the current request is allowed to proceed. but in this article, we will specifically discuss Spring Cloud Gateway - a reactive Gateway built upon Project Reactor, Spring WebFlux, and Spring Boot 2.0.. First, we will start with an introduction of Spring Cloud Gateway and . If you dont already have m2eclipse installed it is available from the "eclipse To have Intellij work with Checkstyle, you have to install the Checkstyle plugin. Naming Custom Filters And References In Configuration, 18. If you need to suppress some rules (e.g. The redis-rate-limiter.replenishRate property is how many requests per second you want a user to be allowed to do, without any dropped requests. connect-timeout must be specified in milliseconds. In our case, the implementation is trivial: It is so simple in this case because were using another built-in filter, ModifyResponseBodyGatewayFilterFactory, to which we delegate all the grunt work related to body parsing and type conversion. Here, well assume that payloads are relatively small, so we dont have to worry about the memory requirements to store the received object. Let's discuss each of those cases in more detail. The following listing configures a RequestSize GatewayFilter: The RequestSize GatewayFilter factory sets the response status as 413 Payload Too Large with an additional header errorMessage when the request is rejected due to size. It may be the integer value 404 or the string representation of the enumeration: NOT_FOUND. Predicates and filters are specific to routes. Use Git or checkout with SVN using the web URL. The RemoveResponseHeader GatewayFilter factory takes a name parameter. You can do so by running this script: In order to setup Intellij you should import our coding conventions, inspection profiles and set up the checkstyle plugin. Did a developer include a header indicating an API version? per-route http timeouts configuration via configuration, per-route timeouts configuration using Java DSL, Example 64. to the exchange attributes. The actual test uses this WebTestClient to drive both the spun SCG and the backend: In this article, weve shown how to access the response body of a backend service and modify it using the Spring Cloud Gateway library. Once a request has been marked as routed, other routing filters will not route the request again, keyResolver is a bean that implements the KeyResolver interface. or check if an exchange has already been routed. *) and the replacement /${remaining}. Here, well use one thats commonly used by the out-of-the-box filters: AbstractGatewayFilterFactory, a templated base class, where T stands for the configuration class associated with our filter instances. The response is put in the ServerWebExchangeUtils.CLIENT_RESPONSE_ATTR exchange attribute for use in a later filter. The default list of headers that is removed comes from the IETF. Temporary bursts can be allowed by setting burstCapacity higher than replenishRate. The AddRequestHeader GatewayFilter factory takes a name and value parameter. Just commit it and push the change. The next argument is the received body, already converted to the informed in-class. Setting this value to zero blocks all requests. The PrefixPath GatewayFilter factory takes a single prefix parameter. To remove any kind of sensitive header, you should configure this filter for any routes for which you may want to do so. Please point it to the Spring Cloud Builds, 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. The following example configures a cookie route predicate factory: This route matches requests that have a cookie named chocolate whose value matches the ch.p regular expression. A burst of 20 is allowed, but, in the next second, only 10 requests are available. install wscat. See the Spring Cloud Project page for details on setting up your build system with the current Spring Cloud Release Train. GatewaySampleApplication.java, 4. They can also be So, if the downstream server responded with a X-Response-Red:1234, this is replaced with X-Response-Red:Blue, which is what the gateway client would receive.