In this blog, you will learn a way to switch the user credentials while accessing the backend in a multitenancy environment on SAP Cloud Platform. I’ll start with explaining multitenancy followed by provider and tenant sub accounts, tenant on-boarding and off-boarding and then we will move to User switch.
Please pay attention to the fact that this is one of possible solution to achieve user switch and readers are free to come up with their suggestions.
I would like to thank Naresh Pidugu and Vaibhav Agarwal for their ideas while implementing the concept of User Switch.
What is User Switch?
Let’s consider a scenario where more than one customer/ company needs the same application with company specific data and each customer has multiple end users who need to access this application. Each user in each company is provided its own credentials to access the application. But the same user credential does not exist in the backend system because the customer does not want to do user management in it. Customer is ready to take one company’s credential for backend and wants to internally switch the user credential to company’s credential without providing these credentials to the user. We will come back to the details after covering the basic concepts.
Multi tenant environment on SAP Cloud Platform
- Develop and run a multi-tenant application in SAP Cloud Platform
- Share the application with multiple consumers/ tenants simultaneously
- Each consumer accesses the application by a dedicated URL which identifies their tenant. This URL gets generated when the tenant subscribes the application.
Where to host the application?
An application provider has a global account. It contains
- Provider Sub account (where the multi-tenant business application is hosted)
- Customer Sub accounts (dedicated to each consumer or tenant)
- Once the multitenant application is developed, the developer must register it as a SaaS registry. This will enable the tenants to subscribe the application.
Each customer and the application provider have a separate Global account.
- Once the multi tenant application is developed, it should be commercialized in CIS.
Tenant onboarding and offboarding:
Subscription is initiated from the customer subaccount.
The SaaS Provisioning service requires to define the following API end points:
PUT – callback/v1.0/tenants/*
DELETE – callback/v1.0/tenants/*
PUT is used to onboard a tenant when a customer subscribes to the application
DELETE is used to offboard a tenant when a customer unsubscribes to the application.
Click on subscribe and you will see a subscribed application which you can open via a click on “Go to Application”
Once the link gets generated, map it in the routes on provider account.
Let’s take an example to understand user switch (below details are based on Approach 1 in this blog)
We have a multi-tenant application App1 available as a SaaS registry. Two customers C1 and C2 need this application. C1 and C2 will have their respective tenant sub-accounts via which they will subscribe App1 and a unique URL will get generated.
Each user of C1 will use URL1 and each user of C2 will use URL2 and their credentials will get authenticated using respective customer IDP.
The users of C1 and C2 can now access the application but they do no have individual backend credentials that can allow App1 to interact with the backend.
Each company has its own backend credentials let’s call it as P1 and P2 for C1 and C2, respectively.
We need to switch the credentials of each user of Company C1 to P1 and the credentials of each user of Company C2 to P2 while they are accessing the application APP1.
How to achieve this?
- Th URL for each tenant is unique and contains tenant information and can be used to detect the tenant of the user.
- Maintain a destination per company. A destination consists of the system information and credentials. The system information for each company would be same but the credentials are different i.e. the room is same but the door to enter the room is different. Therefore, we require a separate destination for each company. Let’s call them as MTAppDest1 and MTAppDest2.
- Maintain user-provided variable which contains a mapping of tenant versus destination as you can see below.
- So, once the application needs to interact with the backend it will
- read the URL and detect the tenant id
- then will read the user provided variable present in provider sub-account which consists of the mapping of tenant id and destination.
- Once it knows the destination then it will read the destination configuration and access the backend system.
What is required when a new customer is to be onboarded?
- Provide a new tenant account (sub-account in this case)
- Subscribe the application
- Create a destination in the Provider sub-account
- Add a mapping in the user-provided variable
- Add the new route to the routes
Note: When you have to follow Approach 2 as per your requirement and in case commercialization process is taking time then in the mean time you can deploy the application using approach 1 and temporarily register it as a SaaS registry to test the onboarding, offboarding and the application behavior from another subaccount within the same global account. This will help you to be ready with a tested application.