How To Maintain Session In Spring Boot MicroService - spring

Question

I am new to Spring MicroService i know how to handle session in Springboot monolithic application but can you please tell me how to handle session in microservice when we communicate with another microservice from one, and how to handle session if multiple instance of a microservice is running.

Answer 1

It's a complicated question and needs some extra logic to be written.
So, all methods, that may be called from one service to another should be parameterized and look like this:
public int externalCall(Session session)
{
if(sessionManager.isAliveSession(session)
{
sessionManager.touch(session);
//do some actions
}
else
{
throw new UnknownSessionException();
}
}
Then you should have one more service or module to deal with sessions. In my code I called it sessionManager.
It may possibly have such methods:
public interface SessionManager
{
/**
* to create session object in database, for example,
* with expiration date, create date etc.
*/
public void createSession();
/**
* to set the fact, that this session is
* still used and update its expiration time
*/
public void touch(Session session);
/**
* checks if session with this
* id is not expired.
*/
public boolean isAliveSession(Session session);
}
Here is an example how to call externalCall from the other service.
You will need to create class like this to perform session-based calls:
public class SessionTemplate
{
private SessionManager sessionManager;
private AtomicReference<SessionTO> session = new AtomicReference();
public <T> T execute(Callback<T> callback) {
Session session = this.getSession();
try {
return callback.doInSeance(session);
} catch (UnknownSessionException e) {
// exception may happen in externalCall method
session = this.createSession(session);
return callback.doInSeance(session);
}
}
private Session getSession() {
if (this.session.get() == null) {
synchronized(this) {
if (this.session.get() == null) {
this.session.set(this.createSession());
}
}
}
return (Session)this.session.get();
}
private Session createSession()
{
// create session in your DB
return sessionManager.createSession();
}
}
Now your remote calls will be performed like this:
public int getSmthFromRemote()
{
return sessionTemplate.execute(session -> microService.externalCall(session));
}