I read everywhere #RefreshScope for cloud bus applications work with RabbitMQ and Kafka. But in my case, I am using AWS Parameter store. I want all my client instances to be refreshed automatically without rebuilding servers on AWS Console.
I created AWS Eventbridge from Paramstore to notify Kinesis Stream but I am not able to figure out how can it notify all my client nodes instead of load balancer refresh to only one node(instance).
Thank you for responding in advance.
I've never worked with AWS Eventbridge / Kinesis, however:
#RefreshScope is something that belongs to spring cloud and not not AWS.
More precisely, beans defined with this scope will be re-loaded by spring without reloading the whole application context "dynamically" when configuration changes in spring boot cloud configuration service. Usually this means that you don't have to restart the application.
Now, spring boot microservice should be deployed with actuator that exposes refresh endpoint. Calling this endpoint manually will cause all the #RefreshScope beans to reload.
Here is the source code of the RefreshEndpoint:
#Endpoint(id = "refresh")
public class RefreshEndpoint {
private ContextRefresher contextRefresher;
public RefreshEndpoint(ContextRefresher contextRefresher) {
this.contextRefresher = contextRefresher;
}
#WriteOperation
public Collection<String> refresh() {
Set<String> keys = this.contextRefresher.refresh();
return keys;
}
}
As you see, its merely invokes contextRefresher.refresh(), ContextRefresher is a bean that you can inject in your custom code that will listen to the changes coming from AWS Parameter store (it should somehow invoke it directly or maybe send some message that you could consume or something).
If you're using spring-cloud-bus (disclaimer, I've never worked with it) it exposes the bus-refresh endpoint as well (pretty similar mechanism to what I've described), read spring-cloud-bus documentation for more details.
Thank you Team for sharing info.
Here is what I did to make it work. Added these two libraries to my project
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-stream-binder-kinesis</artifactId>
<version>1.1.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-bus</artifactId>
</dependency>
And added these two entries into bootstrap.properties
cloud.aws.region.static=us-east-1
cloud.aws.stack.auto = false
And refreshing using this endpoint (/bus-refresh)
Related
I want to cache the following getMessagesList method. I want to call one time When user log into the system. Therefor I think caching is the best solution for that. And I need to remove when user log out. How I can do this.
public List<String> getMessagesList(String username)
{ // return messages list in DB by username}
My project was create using Maven 4.0 and Spring MVC. spring version 5.3
Assuming you use Spring Security as part of your app, it should be managing your session, and every time you log out, it will create a new session. Unless you had posted this code, I'm not going to be able to help you there. However, assuming you can log in/out, this should be covered already.
As for the cacheing, in general, this sounds like a Database Caching need, which is something that you would use Spring Boot Caching on.
To use this in Spring Boot, you would add the following dependency to maven (or the equivalent in Gradle, etc):
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
Adjust your application to allow using Cacheing, which can be done by adding the annotation #EnableCaching to your Spring Boot application
#SpringBootApplication
#EnableCaching
public class MyApplication {
...
}
Create a Java Service Object, called something like MessagesService.class:
#CacheConfig(cacheNames={"Messages"})
public class MessagesService {
#Cacheable(value="cacheMessages")
List<String> getMessages() {
//access the database to load data here
...
}
...
}
I am developing a module with spring boot in my backend where i need to use Redis through GCP Memory Store. I have been searching in forum and even the "oficial documentation" about memory store but i cannot understand how to connect to memory store with my spring boot app.
I found a google code lab but they use a Compute Engine VM to install spring boot and then save and retrieve information from memory store. So i tried to do it like that in my local spring boot but it didnt work because throws an error saying:
Unable to connect to Redis; nested exception is io.lettuce.core.RedisConnectionException: Unable to connect to 10.1.3.4
the codelab i mentioned earlier says that you only have to add this line to your application.properties:
spring.redis.host=10.1.3.4
as well as the annotation #EnableCaching in the main class and #Cachable annotation in the controller method where you try to do something with redis.
the method looks like this:
#RequestMapping("/hello/{name}")
#Cacheable("hello")
public String hello(#PathVariable String name) throws InterruptedException {
Thread.sleep(5000);
return "Hello " + name;
}
i dont know what else to do. Notice that i am new on this topic of redis and memory store.
Anyone can give me some guidance on this please?
thanks in advance
codelab url: https://codelabs.developers.google.com/codelabs/cloud-spring-cache-memorystore#0
See this documentation on how to setup Memorystore Redis instance.
Included in the documentation is how you can connect and test your Memorystore instance from different computing environments.
There's also a step by step guide on how SpringBoot can use Redis to cache with annonations.
Add the Spring Data Redis starter in your pom.xml if you're using Maven for your project setup.
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
Add this configuration in your application.properties file:
spring.redis.host=<MEMORYSTORE_REDIS_IP>
# Configure default TTL, e.g., 10 minutes
spring.cache.redis.time-to-live=600000
Turn on caching capability explicitly with the #EnableCaching annotation:
#SpringBootApplication
#EnableCaching
class DemoApplication {
...
}
Once you configured the Spring Boot with Redis and enabled caching, you can use the #Cacheable annotation to cache return values.
#Service
class OrderService {
private final OrderRepository orderRepository;
public OrderService(OrderRepository orderRepository) {
this.orderRepository = orderRepository;
}
#Cacheable("order")
public Order getOrder(Long id) {
orderRepository.findById(id);
}
}
I went through lots of tutorials regarding this but could not get this done.
Here is my table structure for this.
Application Profile Label prop_key value
masking dev latest test-property message
I have a cloud config server which should integrate with JDBC backend. Here is my application.properties in config server
server.port=8082
spring.application.name=masking
management.endpoints.web.exposure.include=*
spring.datasource.url=jdbc:postgresql://localhost:8000/finos?currentSchema=xlabs
spring.datasource.username=mufgdev
spring.datasource.password=XXX
spring.profiles.active=XXX
spring.cloud.config.server.jdbc.sql=SELECT prop_key,value from xlabs.properties where application=? and profile=? and label=?
spring.cloud.config.server.jdbc.order=1
With this configs if I enter http://localhost:8082/masking/dev/latest response will show the results as I want.
I want to consume properties in client side with the following configs in bootstrap.properties
spring.application.name=masking
spring.cloud.config.uri=http://localhost:8082
spring.cloud.config.label=latest
spring.cloud.config.profile=dev
And in my client side
#RestController
#RefreshScope
public class TestController {
#Value("${test-property}")
private String aConf;
#GetMapping("/message")
String message() {
String name =aConf ;
return name;
}
}
This gives java.lang.IllegalArgumentException: Could not resolve placeholder 'test-property' in value "${test-property}"
Can anyone comment on this?
Thanks.
This issue comes with the latest Spring boot release, All the above code segments steps all okay, But by default Spring has disabled bootstrap. So you have to enable them by adding
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-bootstrap</artifactId>
</dependency>
No need add for older versions of the Spring boot projects.
Context: I need to provide a way to change parameter values during production on lower performance cost as possible.
Goal: I want change annotation values on fly and apply it at once on all microservices instances.
Personal background and limitations: I know I can use Spring Cloud Config to change parameters on the fly like explained in this article and I Know there is some challenges and pitfalls involved on changing annotations on the fly also like discussed in stackoveflow question.
I know that Spring Cloud Config can be used for setting up a centralized configuration applied to all microservice instances during boot/start. I have used it a bit. I am wondering if I can use it for centralizing parameters that can affect customized annotations on fly.
An imagined solution is:
... whenever I need somepRopertyValue
#Value("${config.somePropertyValue}")
private String somePropertyValue;
#Bean
public String somePropertyValue(){
return somePropertyValue;
}
A config client in all microservices endpoint that must be call not only when the application start but whenever somePropertyValue managed in Spring Cloud Config Server bootstrap.properties is updated:
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#SpringBootApplication
public class SpringConfigClientApplication {
public static void main(String[] args) {
SpringApplication.run(SpringConfigClientApplication.class, args);
}
}
#RefreshScope
#RestController
class MessageRestController {
#Value("${server.somePropertyValue:Unable to connect to config server}")
private String somePropertyValue;
#RequestMapping("/server/somePropertyValue")
String getSomePropertyValue() {
return this.somePropertyValue;
}
}
And somehow somePropertyValue is maintened in Spring Cloud Config and if change during production time it affects on demand everywhere somePropertyValue is annoted in all microservice instances.
I am currently reaching this behaviour by adding a kafka consumer in all SpringBoot microservices that listen/observe a topic and when it receives a new messagge it changes on the fly the parameter value. It seems so odd that I created a Kafka dependency in all company microservices. Since I have used Spring Config for a bit similar scenario I am wondering if there is a better alternative using some out-of-box Spring approach. Also performance is highly important in my case and a bit delay on syncronize all parameters isn't an issue. By delay I mean that two or three seconds to update parameters in all microservices isn't an issue.
There are two ways to do that:
i- There's a refresh endpoint, and you can actually call that for a service, and it'll actually refresh its configurations without restarting itself, which is pretty neat. e.g. MS-A is listing on 8080 then do a POST request at this endpoint:
localhost:8080/refresh.
NOTE: Spring Actuator actually adds a RefreshEndpoint to the app automatically when we annotate a controller in MS-A with #RefreshScope.
ii- What you can also do is use Spring Cloud Bus, and broadcast an event, and then every service listens on that and refreshes itself. That's handy if you have dozens of services all using the Config Server, and you don't want to go one by one and hit a /refresh endpoint as we have did in 1st approach. You just want to broadcast a message to a bus and have all these things automatically pick it up.
Reference: Both concepts I've learnt while taking course at Pluralsight
I have been trying to collect micrometer metrics in a non springboot application and expose them to prometheus.I have added the following dependency and the test method for the same.I would like to know how to proceed and expose the collected metrics to prometheus from my non spring boot application(traditional spring application).
<dependency>
<groupId>io.micrometer</groupId>
<artifactId>micrometer-registry-prometheus</artifactId>
<version>1.2.0</version>
</dependency>
public string testmetrics(){
private PrometheusMeterRegistry registry = new PrometheusMeterRegistry(PrometheusConfig.DEFAULT);
registry.counter("ws metric collection","tktdoc metrics");
String metricsInfo = registry.scrape();
return metricsInfo;
}
You practically have to expose an HTTP endpoint and configure Prometheus with it; the HTTP endpoint will supply the data for the scrapes.
An example showing how to add the HTTP endpoint by starting up an HTTP Server (your application may already be using one) is here.