Spring cloud config git refreshRate behaviour - spring-cloud-config

Question

I am trying to setup Spring Cloud Config Server and want to enable auto refresh of properties based on changes to the backing git repository.
Below is the bootstrap.yml of the server.
server:
port: 8080
spring:
application:
name: my-configserver
cloud:
config:
server:
bootstrap: true
git:
uri: /Users/anoop/Documents/centralconfig
refreshRate: 15
searchPaths: {application}/properties
bus:
enabled: true
As per the documentation spring.cloud.config.server.git.refreshRate determines
how often the config server will fetch updated configuration data from
your Git backend
I see that the config clients are not notified of changes, when the configuration changes. I have not configured a git hook for this and was hoping that just setting the property would do the job.
Anoop

Answer 1

Since you have configured the refreshRate property, whenever config client (other applications) call config server to fetch properties (this happens when either the application starts or application calls /actuator/refresh endpoint), they will get properties which were fetched 15 seconds (your refreshRate) old.
By default the refreshRate property is set to 0, meaning any time client applications ask for property config server will fetch latest from GIT.
I don't think there is any property which lets your client apps get notified in case of change/commits in the GIT. This is something your app needs to do by calling actuator/refresh endpoint. This can be done programmatically using some scheduler (though I wouldn't recommend that).

Answer 2

By default, the config client just reads the properties in git repo at startup and not again.
You can actually have a way to workaround by force bean to refresh its configuration from the config server.
First, you need to add #RefreshScope annotation in the bean where config needs to be reloaded.
Second, enable spring boot actuator in application.yml of config client.
# enable dynamic configuration changes using spring boot actuator
management:
endpoints:
web:
exposure:
include: '*'
And then config a scheduled job (by using #Scheduled annotation with fixedRate,...). Of course, fixedRate should conform with refreshRate from config server.
And inside that job, it will execute the request as below:
curl -X POST http://username:password#localhost:8888/refresh
Then your config client will be notified changes in config repo every fixRate interval.

Answer 3

The property spring.cloud.config.server.git.refreshRate is configured in the Config Server and controls how frequently it is going to pull updates, if any, from Git. Otherwise, the Config Server's default behaviour is to connect to the Git repo only when some client requests its configuration.
Git Repo -> Config Server
It has no effect in the communication between the Config Server and its clients.
Config Server -> Spring Boot app (Config Server clients)
Spring Boot apps built with Config Server clients pull all configuration from the Config Server during their startup. To enable them to dynamically change the initially loaded configuration, you need to perform the following steps in your Spring Boot apps aka Config Server clients:
Include Spring Boot Actuator in the classpath, for example using Gradle:
implementation 'org.springframework.boot:spring-boot-starter-actuator'
Enable the actuator refresh endpoint via the management.endpoints.web.exposure.include=refresh property
Annotate the Beans holding the properties in your code with #RefreshScope, for example:
#RefreshScope
#Service
public class BookService {
#Value("${book.default-page-size:20}")
private int DEFAULT_PAGE_SIZE;
//...
}
With the application running, commit some property change into the repo:
git commit -am "Testing property changes"
Trigger the updating process by sending a HTTP POST request to the refresh endpoint, for example (using httpie and assuming your app is running locally at the port 8080:
http post :8080/actuator/refresh
and the response should be something like below indicating which properties, if any, have changed
HTTP/1.1 200
Connection: keep-alive
Content-Type: application/vnd.spring-boot.actuator.v3+json
Date: Wed, 30 Jun 2021 10:18:48 GMT
Keep-Alive: timeout=60
Transfer-Encoding: chunked
[
"config.client.version",
"book.default-page-size"
]