ServiceA uses a RestTemplate, created using a new instance of RestTemplateBuilder (not the default one created by Spring), to send requests to third-party services.
#Service
public class ServiceA {
private static final String URL_B = "...";
private RestTemplate restTemplate;
public ServiceA() {
restTemplate = new RestTemplateBuilder()
.uriTemplateHandler(new UriTemplateHandler() {
//...
})
.build();
}
public ResponseB getResponseAForServiceB() {
return restTemplate.getForObject(URL_B, ResponseB.class);
}
}
When the Spring Boot app starts up, requests made by ServiceA to ServiceB (third-party) will succeed without any issues. After about 1-1.5 hours of no requests, the first request made by ServiceA to ServiceB will cause a connection timeout for failing to read but a second request will succeed. What is causing the connection to not be able to read and timeout after being idle for a bit?
Related
I want to use OAuth2 ClientCredentials flow for inter service communication between two Resource Servers. Everything works fine except that i am not able to use service name (Ribbon Load Balancer feature) instead of hostname in my OAuth2RestTemplate calls to remote resource server.
One of my Resource Server (that calls another Resource Server) has below configuration:
Spring Boot 1.5.13
Spring Cloud Edgware.SR3
build.gradle contains entries for eureka and ribbon
compile('org.springframework.cloud:spring-cloud-starter-ribbon')
compile('org.springframework.cloud:spring-cloud-starter-eureka')
#Configuration
class RestTemplateConfig {
#Bean
#ConfigurationProperties("security.oauth2.client")
public ClientCredentialsResourceDetails oauth2ClientCredentialsResourceDetails() {
return new ClientCredentialsResourceDetails();
}
#LoadBalanced
#Bean(name = "oauthRestTemplate")
public OAuth2RestOperations oAuthRestTemplate(ClientCredentialsResourceDetails oauth2ClientCredentialsResourceDetails) {
return new OAuth2RestTemplate(oauth2ClientCredentialsResourceDetails);
}
}
Service Consuming this OAuth2RestTemplate
#Service
class TestService {
#Autowired
#Qualifier("oauthRestTemplate")
private OAuth2RestOperations oAuth2RestOperations;
public void notifyOrderStatus(long orderId, OrderStatus newStatus) {
oAuth2RestOperations.exchange("http://notification-service/api/order/{id}/status/{status}", HttpMethod.POST, null, Void.class, orderId, newStatus.name());
}
}
Exception appears while invoking remote service using service name i.e. http://notification-service instead of actual hostname and port of remote resource server. If I use actual hostname + port, then everything works fine but I don't want my one resource to know host/post of another resource server.
Exception:
Caused by: java.net.UnknownHostException: notification-service
I have few questions:
If my RestTemplate is annotated with #LoadBalanced, then everything works fine. Does OAuth2RestTemplate support this annotation and can we use service name instead of hostname? If yes, any reference or documentation would be appreciated.
Is it a good idea to use oauth2 client credentials for inter service security between two resource servers? I do not see any samples for the same in documentation?
#LoadBalanced RestTemplate works when we use RestTemplateCustomizer to customize the newly created OAuth2RestTemplate, as shown in the below code:
#Bean(name = "MyOAuthRestTemplate")
#LoadBalanced
public OAuth2RestOperations restTemplate(RestTemplateCustomizer customizer, ClientCredentialsResourceDetails oauth2ClientCredentialsResourceDetails) {
OAuth2RestTemplate restTemplate = new OAuth2RestTemplate(oauth2ClientCredentialsResourceDetails);
customizer.customize(restTemplate);
return restTemplate;
}
Using service name instead of actual host name works fine using this RestTemplate.
I have a system that implements 4 micro-services. The four services need to occasionally share information and they do it via RESTful requests using Spring's RestTemplate. Currently about 5%-10% of the requests fail with an exception like:
org.springframework.web.client.ResourceAccessException: I/O error on POST request for "https://otherservice.com/path": Connection reset; nested exception is java.net.SocketException: Connection reset
Again, this appears random and only fails about 5%-10% of the time. I have tried multiple things but nothing seems to work. Currently I am trying this:
Configuration:
#Configuration
public class BeanConfiguration {
#Bean
public RestTemplate restTemplate() {
ClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(HttpClients.createDefault());
return new RestTemplate(requestFactory);
}
}
Service:
#Autowired
public MyService(RestTemplate restTemplate) {
this.restTemplate = restTemplate;
}
public Contact addContact(Contact contact) {
HttpEntity<Contact> entity = new HttpEntity<>(contact, authenticationTokenInfo.setTokenHeaders());
ResponseEntity<Contact> response = restTemplate.exchange(contact_base_url, HttpMethod.POST, entity, Contact.class);
return response.getBody();
}
I have tried a number of different approaches and nothing has made any difference. I tried this for example:
#Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
return builder.build();
}
I am logging all of the requests in each of my micro-services and it doesn't appear that the requests are actually hitting the other services. They just fail. According to the logs they fail in less than 50 ms so it isn't a timeout issue. For a couple of them I have implemented an exponential back-off retry but that isn't really a viable solution.
I also faced with same problem. Seems like the problem is with idle connections in pool.
This resolve problem in my case and no any error occasionally occurred
HttpClient httpClient = HttpClients
.custom()
.evictIdleConnections(60000, TimeUnit.MILLISECONDS)
.build();
HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(httpClient);
I am using spring cloud: Spring Boot Application with Eureka + Ribbon default configuration.
I am using 2 RestTemplate configurations, both are #LoadBalanced currently and both of them have the same UriTemplateHandler.
I declared both the #SpringBootApplication and also the #RibbonClient(name="${service.name}") annotations.
My problem is:
When I am trying to access the first configured RestTemplate, the RestTemplate resolvs (by eureka and load balancing by ribbon) to a server , not as I requested as configured in the UriTemplateHandler.
For example: in the UriTemplateHandler I configured "A-Service" and in real time the restTemplate sends the httpRequest to "B-Service"
This behavior happens often, not just for a specific request, but it looks like it only happens when I'm accessing the first configured RestTemplate.
Is it a problem to use 2 RestTemplate with the same uri?
I have no idea why it happens, please advise.
When creating these rest templates as beans, name them uniquely, like e.g.
#LoadBalanced
#Bean("integrationRestTemplate")
public RestTemplate restTemplate() throws Exception {
// build and return your rest template
return ....
}
Then, the other one might be without any specific name e.g.
#Bean
public RestTemplate restTemplate() {
return new RestTemplate();
}
Now, if you have these two distinctive rest templates, you can inject the former one e.g. like that:
#Service
public class MyService {
private final RestTemplate restTemplate;
public ApplicantService(#Qualifier("integrationRestTemplate") RestTemplate restTemplate) {
this.restTemplate = restTemplate;
}
// service methods
...
}
Basically, the point is you can choose whatever rest template you want, by specifying a #Qualifier.
I am borrowing the below the code from Spring blog here.
#SpringBootApplication
#EnableEurekaClient
#EnableFeignClients
public class Application {
public static void main(String[] args) {
new SpringApplicationBuilder(Application.class)
.web(false)
.run(args);
}
}
#Component
class DiscoveryClientExample implements CommandLineRunner {
#Autowired
private DiscoveryClient discoveryClient;
#Override
public void run(String... strings) throws Exception {
discoveryClient.getInstances("photo-service").forEach((ServiceInstance s) -> {
System.out.println(ToStringBuilder.reflectionToString(s));
});
discoveryClient.getInstances("bookmark-service").forEach((ServiceInstance s) -> {
System.out.println(ToStringBuilder.reflectionToString(s));
});
}
}
#Component
class RestTemplateExample implements CommandLineRunner {
#Autowired
private RestTemplate restTemplate;
#Override
public void run(String... strings) throws Exception {
// use the "smart" Eureka-aware RestTemplate
ResponseEntity<List<Bookmark>> exchange =
this.restTemplate.exchange(
"http://bookmark-service/{userId}/bookmarks",
HttpMethod.GET,
null,
new ParameterizedTypeReference<List<Bookmark>>() {
},
(Object) "mstine");
exchange.getBody().forEach(System.out::println);
}
}
There are two options of consuming microservice endpoints from other microservices.
RestTemplate - provides load balancing feature, which load balances the request. But if I have a service running in 3 nodes, does RestTemplate knows if one node is down or responding and "intelligently" load balance between just two of it.
Using DiscoveryClient to get a service instance and make request (as demonstrated above). In this case, though not load balanced, I think the service instance returned is responsive.
The latter loses load balancing feature but provides an active service instance
The former load balances but the resultant instance may be inactive.
I am wondering to which is the preferred one to use?
Please correct me if my understanding above is incorrect.
The first option of using resttemplate is a better option
We just need to annotate the resttemplate with
#LoadBalanced and have a zuul proxy server as the edge server. If we do that then any request to the edge server will be load balanced by default with ribbon and the resttemplate will route the request in a round robin fashion.
If we use a Discoverclient then we cannot route teh request across various instances.
I have a web app that is using Bayeux to handle Comet connections. I initialize a BayeuxServer and tie it into Spring annotations and it all works fine, listening on selected channels and responding.
I have a Jersey annotated class and an annotated Bayeux service as shown below. The idea is I wanted to be able to control resources via Rest from an individual web app, and then right after the resource is changed, do a server push via Comet to all other applicable clients to tell them to update their information.
Here is the problem: A Bayeux Service is created when the webapp is deployed, setting up proper channels to listen on and monitoring clients. There should only be one instance of this. When Jersey attempts to use the Bayeux service it creates a whole new service, when it should be using the original one. This new service doesn't have the BayeuxServer properly injected so I can't access client information through it.
It makes since that this should be doable, but I don't seem to understand how to inject these things properly via annotations. Can anyone point me in the right direction?
Jersey Annotated Class:
#Path("JsonTest")
public class JsonTest {
#Context
Request request;
#Context
UriInfo uriInfo;
#Context
ResourceContext resourceContext;
protected final Logger log = Logger.getLogger(getClass());
public JsonTest() {
}
#DELETE
#Path("{id}")
public void deleteJson(#PathParam("id") String id) {
JsonTestDao.instance.getModel().remove(id);
log.info("Deleted Json..." + id);
log.info("New json: " + JsonTestDao.instance.getModel().toString());
JsonTestService jsonTestService = resourceContext.getResource(JsonTestService.class);
jsonTestService.sendUpdate();
}
}
BayeuxService:
#Named
// Singleton here didn't seem to make a difference
#Service
public class JsonTestService {
protected final Logger log = Logger.getLogger(getClass());
#Inject
private BayeuxServer bayeux;
#Session
private ServerSession serverSession;
#PostConstruct
public void init() {
log.info("Initializing JsonTest Bayeux HelloService...");
log.info("Current sessions are: " + bayeux.getSessions().toString());
}
#Listener("/cometd/JsonTest")
public void jsonTestHandler(ServerSession remote, ServerMessage.Mutable message) {
}
public void sendUpdate() {
//bayeux.newMessage(); // Need a method that the Jersey class can call to notify changes
log.info("Bayeux server should be sending an update now...");
}
#PreDestroy
public void destroy() {
log.info("Destroying JsonTest Bayeux HelloService...");
}
}
See Jersey and spring integration - bean Injections are null at runtime.
Another question I asked. Both of these stem from the same problem involving properly setting the Jersey dependency and integrating it with spring.