I am implementing a Spring Boot application which will be providing a multitenant environment. That is achieved in my case by using a database schema for each customer. Example see this project.
Now I am wondering how to implement tenant-specific configurations. I am using #ConfigurationProperties to bundle my property values, but these are getting instantiated once and not for each tenant.
What if I would like to use Spring Cloud Config with multiple tenant specific git repository as an configuration backend. Would it be possible when using a jdbc backend for Spring Cloud Config?
Is there any way with default Spring mechanisms or do I have to implement a database based configuration framework myself?
Edit: For example I have two tenants called Tenant1 and Tenant2. Both are running over the same application in the same context and are writing in the database schemes tenant_1 and tenant_2.
Identification of tenants is happening over keycloak (see Spring Keycloak multi tenant example). So I identify the tenantId from the jwt token and select the database connection like described here.
But now I would need the same mechanism for #Configuration beans. Since #Configuration beans are as far as I know Singletons, so there is always ONE configuration per application scope, and not ONE configuration per tenant.
So using Spring Cloud Config Tenant1 is using https://git-url/tenant1, Tenant2 is using Hashicorp Vault as backend and perhaps Tenant3 will be using a jdbc based configuration backend. And all of that in ONE (of course scalable) application.
In case your application uses tenant specific files (html templates etc), the following can be applied. As I have used the below approach for handling many tenants and works fine and easy to maintain.
I would suggest that you maintain a consistent configuration source (JDBC) for all of your tenant configurations. This helps you have a single source that is cacheable and scalable for your application. Also, you could have your tenants navigate to a configuration page to manage their settings and alter them to suit their needs at any point of time on the fly. (Example Settings: Records Per Page, Theme, Logo, Filters etc...)
Having the tenant configuration in files in git will be a difficult task when you wanted to auto-provision tenant's when they sign-up as it will involve couple of distributed services. Having them in a TenantSettings table with the tenantId as a column could help you get the data in no time and will be easy.
You can use Spring Cloud Config for your scenario and it is adoptable. It is easily configurable and provides out of the box features. For your specific scenario, you can have any number of microservices running yet all controlled by one Spring Cloud Config Server which is connected to one Git Repository. Your all microservices are asking configuration properties from Spring Cloud Config Server and it is directly fetching properties from Git Repository. That repository can have multiple property files. It can hold common properties for all the microservices or specific service based configuration properties. If you want to keep confidential properties more securely, that is also made possible via HashiCorp vault. I will leave an image below for you to get a better idea about this concept.
In the below image, you can see the Git Repository with common configuration property files and specific configuration property files for different services yet in same repository.
I will add another image for you to get a better idea how does this can be arranged with application profiles as well.
Finally I will add something additional to show the power of Spring Cloud Config and out of the box features it allows us to play with. You can automatically refresh configuration properties in running application as well. You can configure Spring Cloud Config to do that. I will add an architectural diagram to achieve that.
References for this answer is taken from Spring in Action, Fifth Edition
Craig Walls
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I have 3 microservices on my server Customer, Order and Shipping. I want these 3 services to use the same configuration from the config server. According to the spring cloud document, they said that
The HTTP service has resources in the form:
/secret/{**application**}/{profile}
/secret/{**application**}
/secret/{**defaultContext**}/{profile}
/secret/{**defaultContext**}
where the "application" is injected as the **spring.application.name** in the SpringApplication
so If I want these 3 services to use the same configuration I may have 2 options either use the same spring.application.name, which I don't want to do that, or create a configuration file for each service. It would be nice if I can use the same configuration file for every services since it's easy to maintain and update. Is it possible to do that?
update:
I may need to improve my searching skill lol. I found this document that provides an example on how to do that. Basically, all you need to do is to name the configuration file as application and it will be available to every services.
https://cloud.spring.io/spring-cloud-config/multi/multi__spring_cloud_config_server.html#spring-cloud-config-server-vault-server
I have some properties in my microservice. They are changed a lot so I want to store them somewhere out of microservice so that I don't have to undeploy it again and again. One solution is to store them in database but it will be less efficient that way. Can you advise me a solution where I can store them?
Basically this microservice is used by a vast number of people. I want that file to be read ONCE when microservice is deployed (unless or until there is some change in the file) to minimize the calls.
You should use Spring Cloud Config which enables to use a centralized server which exposes a Git Repo which you can use to store environment specific configuration files (application.properties)
You should go with Centralized configuration, spring cloud supports config server, It is highly recommended for microservice architecture.
For reference: https://spring.io/guides/gs/centralized-configuration/
Basically, you have a centralized place to store all the configurations and don't need the redeploy the application every time you change the configs.
NOTE: in case you change the db properties then probably you need the restart the service
Supposed we had a couple of services service-1,service-2, service-3, we can handle global configurations like DB configs,environment configs etc using an externalized service like spring cloud config server or consul. But what is the best way to handle admin related settings in Micro-services e.g Max funding amount, vat, transaction limit etc setting that don't need a programmer to change ? note multiple services can use these values.
one way of doing this would be creating a bean which loads the data at the start of the app from db. In db you can have a table with admin privileges provide simple insert/update queries to the user who can/wants execute them. This user can be admin of the app who is using your app.
Other way would be creating your own properties/attributes and providing them in application.properties file. You can load those properties any of the beans which you think will need them.
eg (for spring boot):-
spring.max.transaction.limit -- in application.poperties
#Value("${spring.max.transaction.limit}")
private String transactionLimit; -- in the bean
It's well understood that in a microservices architecture, configuration must be externalized.
Tools like zookeeper, etcd or consul are excellent options to store that configuration. However a new layer on top of those services is required in order to provide new functionalities that are fundamental in a configuration server. Ex. versioning; change history; "draft" / published configuration, etc...
I've found spring config server, which is an interesting project and addresses all these concerns using git for handling the above mentioned requirements. However, I'd like avoid using git due to additional required setup. ex. replication, etc...
Do you know any other options other then spring config server?
Our findings have been the same - configuration must be externalized and the notion of "code as config" through the lessons learned from implementing time consuming Puppet/Chef systems.
We're building a microservices and API orchestration system at LunchBadger. We also uses git - but it's encapsulated into our system that we provide as a service, because we want configuration to be externalized AND dovetail into whatever CI/CD pipeline infrastructure you may have or are looking to adopt. We also provide visualization on top of microservices and APIs so that you can get an idea of the topology of your once monolithic app in the form of many microservices.
You can look into Microconfig.IO and it's Microconfig Server. It's deployed via docker and configured via 3 env vars. It still use git repo for config storage, but that's actually a proper way to go. As a bonus you get a powerful templating functionality designed explicitly to handle app configuration
I have a REST web service exposed at http://server:8080/my-production-ws by JBoss (7). My spring (3.2) configuration has a datasource which points to a my-production-db database. So far so good.
I want to test that web service from the client side, including PUT/POST operations but I obviously don't want my tests to affect the production database.
Is there an easy way to have spring auto-magically create another web service entry point at http://server:8080/my-test-ws or maybe http://server:8080/my-production-ws/test that will have the exact same semantics as the production web service but will use a my-test-db database as a data source instead of my-production-db?
If this is not possible, what is the standard approach to integration testing in that situation?
I'd rather not duplicate every single method in my controllers.
Check the spring Profiles functionality, this should solve the problem. With it its possible to create two datasources with the same bean name in different profiles and then activate only one depending on a parameter passed to the the JVM.