I am currently using the spring cloud gateway project to build simple api gateway, the plan was to persist the route in mongodb, then refresh, so that the new route can be available. I have done something simple like this to get my route from mongo.
#Bean
public RouteLocator routeLocator(RouteLocatorBuilder builder){
List<CreateAPIRequest> apiRequestList = repository.findAll();
RouteLocatorBuilder.Builder routeLocator = builder.routes();
for (CreateAPIRequest request: apiRequestList) {
routeLocator
.route(r-> {
r.path("/"+request.getProxy().getListenPath())
.filters(f->f.stripPrefix(1))
.uri(request.getProxy().getTargetUrl())
});
}
return routeLocator.build();
}
I was able to create new route in the db, but I am unable to refresh on the fly.
I need to understand how to refresh the routes on the fly.
Thanks
Whenever you wish to update the routes dynamically send a RefreshRoutesEvent. The following component implements the event sending functionality.
#Component
public class GatewayRoutesRefresher implements ApplicationEventPublisherAware {
ApplicationEventPublisher publisher;
#Override
public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
publisher = applicationEventPublisher;
}
public void refreshRoutes() {
publisher.publishEvent(new RefreshRoutesEvent(this));
}
}
Here is a sample showing how to use the component above:
#Autowired
GatewayRoutesRefresher gatewayRoutesRefresher;
...
public void buildRoutes() {
// build your routes basing on your db entries then refresh the routes in gateway
...
gatewayRoutesRefresher.refreshRoutes();
}
You can find a more complete picture of the concept by looking into the following project code: https://github.com/botorabi/HomieCenter
SCG(Spring Cloud Gateway) has been provided RouteDefinitionRepository, you can write your own RouteDefinitionRepository, and implements RouteDefinitionRepository to override getRouteDefinitions method.
You can refer to this class: InMemoryRouteDefinitionRepository
For example:
#Service
public class MongodbDefinitionRepository implements RouteDefinitionRepository {
#Autowired
private RouteConfigDao routeConfigDao;
#Override
public Flux<RouteDefinition> getRouteDefinitions() {
// todo
List<RouteDefinition> routeConfigs = routeConfigDao.findAll();
return Flux.fromIterable(routeConfigs);
}
#Override
public Mono<Void> save(Mono<RouteDefinition> route) {
return route.flatMap(routeDefinition -> {
// todo
return Mono.empty();
});
}
#Override
public Mono<Void> delete(Mono<String> routeId) {
return routeId.flatMap(id -> {
// todo
int delete = routeConfigDao.delete(routeId);
if (delete > 0) {
return Mono.empty();
}
return Mono.defer(() -> Mono.error(new Exception("delete route definition error, routeId:" + routeId)));
});
}
}
How to refresh the routes on the fly
Enable actuator
place this in your application.yml
management:
endpoints:
web:
exposure:
include: gateway
POST http://ip:port/actuator/gateway/refresh
Publish RefreshRoutesEvent
#Service
public class MyPublishBiz implements ApplicationEventPublisherAware {
protected ApplicationEventPublisher publisher;
#Override
public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
this.publisher = publisher;
}
public Mono<Void> refresh() {
this.publisher.publishEvent(new RefreshRoutesEvent(this));
return Mono.empty();
}
}
I went quickly to the repo and the open issues.
And it seems that at the moment the only way to refresh the routes is from Actuator via:
/actuator/gateway/refresh
You can check the discussion here: https://github.com/spring-cloud/spring-cloud-gateway/issues/43
Can you use Consul for persisting your route definitions instead of mongo. Then a simple POST call to the actuator's refresh will reload your route definitions on the fly.
Related
I am using spring cloud gateway to route request to my downstream application
I have the router defined something like below
#Configuration
public class SpringCloudConfig {
#Bean
public RouteLocator gatewayRoutes(RouteLocatorBuilder builder) {
return builder.routes()
.route(r -> r.path("/user/test/**")
.uri("http://localhost:8081/test")
.id("testModule"))
.build();
}
}
Routing works fine, now I need to add a prefilter which can do some pre-condition and get routing path. but not getting how to change uri dynamically .uri("http://localhost:8081/test")
Below is the code I am trying for out in preFilter.
#Component
public class testPreFilter extends AbstractGatewayFilterFactory {
#Override
public GatewayFilter apply(Config config) {
System.out.println("inside testPreFilter.apply method");
return (exchange, chain) -> {
//get headers and do lookup for URI in mapping DB
**//If contains return modify the uri**
return chain.filter(exchange.mutate().request(request).build());
//else 401
};
}
}
so I need to forward from incoming path /user/test/** to http://localhost:8081/test1 or http://localhost:8081/test2 based on db lookup return in my custom filter
You are basically changing the path I believe , so you can do that in this fashion .
Based on the value you get from the database , set the path .
I'm learning how to build an API Gateway using Spring Cloud. I've scoured through the documentation on how to pass a parameter and all examples seem to show them as hardcoded in. But what if I have a dynamic value?
For example I have this type of request: http://localhost:8080/people/lookup?searchKey=jdoe,
How do I pass in the "jdoe" part?
I tried the following code and it works only if I hardcode the value in the code.
i.e., .filters(f -> f.addRequestParameter("searchKey", "jdoe") .
That test also proves that my discovery server (Eureka) is working.
I'm not sure how to access the value using the provided builder methods. It's such a simple scenario but I'm surprised to find out there's not a lot of example or documentation for it so it must be just me.
#SpringBootApplication
#EnableEurekaClient
public class ApiGatewayApplication {
public static void main(String[] args) {
SpringApplication.run(ApiGatewayApplication.class, args);
}
#Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
return builder.routes()
.route("people-service", r -> r.path("/people/active-associates")
.uri("lb://people-service"))
.route(r -> r.path("/people/lookup")
.filters(f -> f.addRequestParameter("searchKey", howDoIPassDynamicValueHere))
.uri("lb://people-service")
.id("addrequestparameter_route"))
.build();
}
This obviously worked when I call the service directly because my microservice controller handles it like this using the #RequestParam...pretty straightforward:
#RestController
#RequestMapping(value = "/people")
public class PersonController {
#Autowired
private PersonService personService;
/**
* Searches by FirstName, Lastname or NetworkId.
*
* #param searchKey
* #return ResponseEntity<List<Person>>
*/
#GetMapping(value = "/lookup")
public ResponseEntity<List<Person>> findPersonsBySearchKey(#RequestParam(name = "searchKey") String searchKey) {
List<Person> people = personService.findActivePersonsByFirstLastNetworkId(searchKey.trim().toLowerCase());
return new ResponseEntity<List<Person>>(people, HttpStatus.OK);
}
}
Thanks to the comments, it started making sense to me. I guess I did overthink when I read the documentation about the filter's addRequestParameter() method. I thought that I would need to use that method if my requests have parameters. Been scratching my head for a day and I can't believe it's that simple. So I got it working by just removing that filter:
#SpringBootApplication
#EnableEurekaClient
public class ApiGatewayApplication {
public static void main(String[] args) {
SpringApplication.run(ApiGatewayApplication.class, args);
}
#Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
return builder.routes()
.route("people-service", r -> r.path("/people/active-associates")
.uri("lb://people-service"))
.route(r -> r.path("/people/lookup")
.uri("lb://people-service"))
.build();
}
}
I'm new to spring cloud gateway.
I've been watching some of the youtube videos from the SpringDeveloper channel and am working on the following example:
#Bean
public RouteLocator myRoutes(RouteLocatorBuilder builder) {
return builder.routes()
.route(r -> r.path("/get")
.addRequestHeader("X-SpringOne", "Awesome")
.uri("http://httpbin.org:80"))
.build();
}
Prior to looking at spring cloud gateway, i've also looked at Spring Netflix Zuul. I understand that in Netflix Zuul, you can create filters by creating a class that extends ZuulFilter and define it as a pre, post, route, etc.
However I was wondering how one can create a PRE/ POST filter using Spring cloud gateway?
Any help/ advice is much appreciated.
Thanks.
For a pre filter here is AddRequestHeader (code is executed before chain.filter() call):
public class AddRequestHeaderGatewayFilterFactory extends AbstractNameValueGatewayFilterFactory {
#Override
public GatewayFilter apply(NameValueConfig config) {
return (exchange, chain) -> {
ServerHttpRequest request = exchange.getRequest().mutate()
.header(config.getName(), config.getValue())
.build();
return chain.filter(exchange.mutate().request(request).build());
};
}
}
For a 'post' filter, here is SetStatus (code is run in lambda in chain.filter(exchange).then()):
public class SetStatusGatewayFilterFactory extends AbstractGatewayFilterFactory<SetStatusGatewayFilterFactory.Config> {
#Override
public GatewayFilter apply(Config config) {
final HttpStatus status = ServerWebExchangeUtils.parse(config.status);
return (exchange, chain) -> {
return chain.filter(exchange).then(Mono.fromRunnable(() -> {
// check not really needed, since it is guarded in setStatusCode,
// but it's a good example
if (!exchange.getResponse().isCommitted()) {
setResponseStatus(exchange, status);
}
}));
};
}
}
Here is a simple example in Kotlin: the URI http://.../customers is mapped to the URI obtained from the discovery service (lb = load balanced) for the service named customer and appended with "/". Furthermore, the forwarded request is enhanced with an additional header entry. Hope this helps.
#SpringBootApplication
class Application {
#Bean
fun routes(builder: RouteLocatorBuilder) = builder.routes {
route {
path("/customers")
filters {
setPath("/")
addRequestHeader("aKey", "aValue")
}
uri("lb://customer")
}
}
}
I am not sure this is the correct way to do it because I am also trying to achieve this behavior, I am thinking if this is something that needs to be done:
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
public class CustomFilter implements GatewayFilter {
#Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
//code for PRE filter
Mono<Void> v = chain.filter(exchange);
//code for POST filter
return v;
}
}
Let me know if that works for you or if you found another solution.
I'm trying to disable a Zuul route to a microservice registered with Eureka at runtime (I'm using spring boot).
This is an example:
localhost/hello
localhost/world
Those two are the registered microservices. I would like to disable the route to one of them at runtime without shutting it down.
Is there a way to do this?
Thank you,
Nano
Alternatively to using Cloud Config, custom ZuulFilter can be used. Something like (partial implementation to show the concept):
public class BlackListFilter extends ZuulFilter {
#Override
public String filterType() {
return "pre";
}
...
#Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
String uri = ctx.getRequest().getRequestURI();
String appId = uri.split("/")[1];
if (blackList.contains(appId)) {
ctx.setSendZuulResponse(false);
LOG.info("Request '{}' from {}:{} is blocked",
uri, ctx.getRequest().getRemoteHost(), ctx.getRequest().getRemotePort());
}
return null;
}
}
where blackList contains list of application IDs (Spring Boot application name) managed for example via some RESTful API.
After a lot of efforts I came up with this solution. First, I used Netflix Archaius to watch a property file. Then I proceeded as follows:
public class ApplicationRouteLocator extends SimpleRouteLocator implements RefreshableRouteLocator {
public ApplicationRouteLocator(String servletPath, ZuulProperties properties) {
super(servletPath, properties );
}
#Override
public void refresh() {
doRefresh();
}
}
Made the doRefresh() method public by extending SimpleRouteLocator and calling its method in the overridden one of the interface RefreshableRouteLocator.
Then I redefined the bean RouteLocator with my custom implementation:
#Configuration
#EnableConfigurationProperties( { ZuulProperties.class } )
public class ZuulConfig {
public static ApplicationRouteLocator simpleRouteLocator;
#Autowired
private ZuulProperties zuulProperties;
#Autowired
private ServerProperties server;
#Bean
#Primary
public RouteLocator routeLocator() {
logger.info( "zuulProperties are: {}", zuulProperties );
simpleRouteLocator = new ApplicationRouteLocator( this.server.getServletPrefix(),
this.zuulProperties );
ConfigurationManager.getConfigInstance().addConfigurationListener( configurationListener );
return simpleRouteLocator;
}
private ConfigurationListener configurationListener =
new ConfigurationListener() {
#Override
public void configurationChanged( ConfigurationEvent ce ) {
// zuulProperties.getRoutes() do something
// zuulProperties.getIgnoredPatterns() do something
simpleRouteLocator.refresh();
}
}
}
Every time a property in the file was modified an event was triggered and the ConfigurationEvent was able to deal with it (getPropertyName() and getPropertyValue() to extract data from the event). Since I also Autowired the ZuulProperties I was able to get access to it. With the right rule I could find whether the property of Zuul
zuul.ignoredPatterns
was modified changing its value in the ZuulProperties accordingly.
Here refresh context should work (as long as you are not adding a new routing rule or removing a currently existing one), if you are adding or removing routing rules, you have to add a new bean for ZuulProperties and mark it with #RefreshScope, #Primary.
You can autowire refreshEndpoint bean for example and apply refreshEndpoint.refresh() on the listener.
Marking a custom RouteLocator as primary will cause problems as zuul already has bean of same type marked as primary.
I am using a spring boot application with #EnableZuulProxy annotation. But I would like to add custom routes during runtime. How is this possible?
Existing documentation only shows static examples, in which routes are defined in the application.yml. Could you point me to code snippets of my use case.
In the ZuulConfiguration I found a possibility to add routes routeLocator().getRoutes().add(route); but they are not applied to the runtime. What am I missing?
Thanks a lot. Cheers
Gerardo
What I did was subclass the SimpleRouteLocator class with my own RouteLocator class. Here is sample of what I did:
public class RouteLocator extends SimpleRouteLocator implements RefreshableRouteLocator {
#Autowired
private ZuulHandlerMapping zuulHandlerMapping;
private Map<String, ZuulRoute> routes = new ConcurrentHashMap<>();
public RouteLocator(TaskExecutor executor, String servletPath, ZuulProperties properties) {
super(servletPath, properties);
executor.execute(new ServiceWatcher());
}
#Override
public Map<String, ZuulRoute> locateRoutes() {
return this.routes;
}
#Override void refresh() {
this.doRefresh();
}
private class ServiceWatcher implements Runnable {
#Override
public void run(){
// Add your routes to this.routes here.
ZuulRoute route1 = new ZuulRoute("/somePath", "http://someResourceUrl:8080");
ZuulRoute route2 = new ZuulRoute("/someOtherPath", "some-service-id");
routes.put("/somePath", route1);
routes.put("/someOtherPath", route2);
zuulHandlerMapping.setDirty(true);
}
}
}
I'm not exactly sure when the ServiceWatcher gets called since in my actual code the ServiceWatcher wraps around a Kubernetes Watcher (since I am running Zuul in an OpenShift environment), but this should provide the gist of how to get started.