Thinking to how Php operates, there are both client and server 'cookies', where the server cookies are session-dependent data that is only seen by the server.
Does Quarkus have anything similar to this? I realize I could make something that would effectively produce this behavior with session client cookies, and internal data maps, but was hoping there might be something along these lines already established.
Quarkus does not really implement any specific session management. The rationale is that it is focused on Microservices, so the system should be as stateless as possible.
What is does have is support for CDI's #SessionScoped if quarkus-undertow is being used.
Related
I am a newbie in Microservices, having theoretical knowledge. I want to make a small application in Microservices. Can anyone please help me with the idea of how to implement microservices?
Thanks in Advance!!
You can create something like a currency conversion app with three microservices like these:
Limit service;
Exchange service;
Currency conversion service.
Limit service and currency conversion service can communicate with the database for retrieving the values of the limits and currencies conversion.
For more info check github.com/in28minutes and look after a microservice repository.
No matter how perfect the code of your microservice is, you may face issues with support and development if the microservice architecture doesn’t work according to certain
rules.
The following rules can help you with microservices a lot:
You have to do everything by yourself because you do not have any Rails and architecture out of the box that can be started by one command. Your microservice should load libraries, establish client connections, and be able to release resources if it stops working for any reason.
It means that being in the microservice folder and having made the 'ruby server.rb' command (a file for starting a microservice) we should make the microservice do the following:
Load used gems, vendor libraries (if used), and our own libraries
Use the configuration (depend on the environment) for adapters or classes of client connections
Establish client connections (permanent connections are meant here). As your microservice should be ready for any shutdowns, you should take care of closing these client connections at such moments. EventMachine and its callback mechanism helps a lot with this.
After that your microservice should be loaded and ready for work.
Incapsulate your communication with the services into abstractly named adapters. We name these adapters based on their role (PubSub, SMSMessenger, Mailer, etc.). This way, we can always change the inner implementation of these adapters by replacing the service if the names of our classes are service agnostic.
For example, we almost always use Redis in our application from the very beginning, thus it is also possible to use it as a message bus, so that we don’t have to integrate any other services. However, with the application growth we should think about solutions like RabbitMQ which are more appropriate for cases like ours.
If your code is designed in such a way that your classes are coupled with each other, do it according to the dependency inversion principle. This will help your code to avoid issues with lib booting.
Learn more here
You can try splitting an existing Monolithic application to gain perspective on microservice architecture.
I wrote this article, which talks about splitting a Django App into microservices. Hope it helps.
How can I share database connection aong in spring cloud module microservices. If there are many microservices how can i use same db connection or should i use db connection per microservices?
In my opinion, the thing that you've asked for is impossible only because each microservice is a dedicated process and it runs inside its own JVM (probably in more than one server). When you create a connection to the database (assuming you use connection pool) its always at the level of a single JVM.
I understand that the chances are that you meant something different but I had to put it on because it directly answers your question
Now, you can share the same database between microservices (the same schema, tables, etc) so that each JVM will have a set of connections opened (in accordance with connection pool definitions).
However, this is a really bad practice - you don't want to share the databases between microservice. The reason is the cost of change: if you (as a maintainer of microservice A) decide to, say, alter one of the tables, now all microservices will have to support this, and this is not a trivial thing to do.
So, a better approach is to have a service that has a "sole responsibility" for your data in some domain. Now, all the services could contact this service and ask for the required data through well-established APIs that should never be broken. In this approach, the cost of change is much "cheaper" since only this "data service" should be changed in a way that it doesn't break existing APIs.
Now regarding the database connection thing: you usually will have more than one JVM that runs the same microservice (like data microservice) so, it's not that you share connections between them, but rather you share the same way of working with database (because after all its the same code).
When dealing with a mircoservice architecture it is usually the case that you have a distributed system.
Most microservices that communicate with each other are not on the same machine, instance or container. Communication between them is most commonly done via http, though there are many other ways.
I would suggest designing mircoservices around a single concern of your application. For example, in your case, you could have a "persistence microservice" that would be responsible for dealing with data persistence operations on a single or multiple types data-stores. It could possibly deal with relational DBs, noSQL, file storage etc. Then, via REST endpoints, you can expose any persistence functionality to the mircoservices that deal with business logic.
A very easy way to build a REST service like this would be with the help of Spring Data REST project.
To answer your actual question, I'm not aware of any way to share actual connections between processes. Beyond that, having many microservices running on the same instance is not a good practice most of the time.
Mircoservices are very popular these days and everybody is trying to transition to them. My advice would be to make sure you don't "over-engineer" your project.
Hope I didn't misunderstand your question, but to be fair it is a little vague. If you could provide a longer more detailed description of your architecture and use case I can suggest more tools/frameworks you can use to achieve your cloudy goals.
First and most important - your microservice should be responsible for handling all data in a given business domain/bounded context. So the question is - 'Why do you need to share database connection between microservices and isn't this a sign you went too far with slicing your system?' Microservice is a tool and word 'micro' may be misleading a bit :)
For more reading I would suggest e.g. https://learn.microsoft.com/en-us/dotnet/standard/microservices-architecture/architect-microservice-container-applications/identify-microservice-domain-model-boundaries (don' t worry, it's general enough to be applicable also to Spring).
tl;dr
Requesting suggestions, guidelines or examples for possibilities to extend spring-boot-adminto use methods other than HTTP requests for health moitoring of non-spring projects like MariaDB.
Full version
There is a requirement to setup a monitoring application using spring-boot-admin. Several of the clients are spring-bootapplications and are easily implemented. There are however a couple of non spring-boot projects like the database server MariaDB.
The question is therefore formulated thusly : Is it possible to extend SBA to monitor the databse status by methods other than HTTP requests. One possible approach, for example, might be to check if it is possible to connect to the application specific TCP port to verify if the db server is still running. However, other possibilities can be exploited too.
One post I found similar to my question was this :
https://github.com/codecentric/spring-boot-admin/issues/504. The key difference here though is that the provided answer still sugests a HTTP approach. The reference guide also does not suggest an alternative.
Should such a possibility exists, a brief outline of the approach or an example implementation would be most welcome.
SBA currently only supports checking health via http. But your DB should be implicitly monitored if you have an according health indicator on your business application.
It should be possible to extend the StatusUpdater#queryStatus() doing a tcp connect if it encounters an health-url beginning with tcp:// instead of http://...
And in case you accomplish that a PR is appreciated :)
in the last line in the following bug report
https://github.com/grails/grails-core/issues/5296
it is stated that;
In an ideal world, it would be possible to turn off HttpSession creation for a whole Controller (all actions) and also turn them off for a particular set of actions.
This is however, a quite old bugreport, so my question is:
is this possible in an upcoming or todays version (1.3.7) of grails? If not, shouldn't it be?
The reason i seek this kind of behavior is due to development of RESTful API's in grails, where the very nature of REST is stateless.
Grails does not create a session if you do not access the implicit session object or use session-scoped services. We have multiple projects running in production, where we do not use sessions. As long as you don't access those objects, you won't see any sessions (no JSESSIONID cookies being sent with the response).
I have an application built with Spring and JPA/Hibernate that is working very well, but I now have a requirement to add Oracle Label Security. This will require the creation of a proxy user assigned with certain roles in addition to the actual user. I am unclear what goes into persistence.xml and what goes in code. Also, if we want to get really fancy, I would love to know how Spring can inject the proper persistence context with the mapping of user to proxy user.
If anyone has experience with this, any insight is appreciated.
thanks.
I'd approach it the following way:
First get the basics of proxy authentication straight. This article looks promising: https://blogs.oracle.com/olaf/entry/using_oracle_proxy_authenticat
Assuming you have Webapplication (or anything else with a single point of entry) create a Filter wich accepts the request, identifies the user, establishes the user in the database using proxy authentication and then forwards the request.
This way your application will only see proper connections with the correct user established. So your Hibernate configuration should not be affected by this.
One warning: You are probably using a connection pools. These pools might not hand you an Oracle implementation of JDBC, but a wrapper through which you have to gain access to the oracle specific features needed. Make sure your application still uses the wrapper other wise the connection pool will not notice any exceptions thrown by the connection, thereby not recognize broken connections and will hand them out over and over again.