Tenant isolated data in shared reusable services

1. A computer-implemented method, comprising:

receiving, at one or more computers, a Tenant request to subscribe to a first Application;

determining, by the one or more computers, a first Service that the first Application consumes;

determining, by the one or more computers, that a Tenant is new to the first Service and in response:

creating, by the one or more computers, a persistency for the Tenant with respect to the first Service,

providing, by the one or more computers, a subscription of the Tenant to the first Service,

associating, by the one or more computers, the subscription to the persistency, and

adding, by the one or more computers, the first Application to the subscription of the Tenant to the first Service;

identifying, by the one or more computers, an already-existing subscription of the Tenant to the first Service; and,

providing, by the one or more computers, a second Application to be added to the already-existing subscription of the Tenant to the first Service;

wherein the already-existing subscription is associated with a reference counter counting number of Applications that consume the first Service and are subscribed by the Tenant;

wherein the number on the reference counter is determined by a number of Service OPEN AUTHORIZATION (OAUTH) Clients provided for each Tenant request received from the Tenant to get a respective Application subscription.

2. The computer-implemented method of claim 1 , wherein the Tenant is a first Tenant and the Tenant request is a first request, the method further comprising:

receiving, at the one or more computers, from a second Tenant a second request to unsubscribe from a third Application;

determining, by the one or more computers, a second Service associated with the third Application;

determining, by the one or more computers, a reference counter number associated with a second Tenant subscription to the second Service; and

determining, by the one or more computers, that the reference counter number is greater than one, and, in response:

requesting, by the one or more computers, removal of the third Application from the second Tenant subscription to the second Service.

3. The computer-implemented method of claim 2 , wherein the persistency is a first persistency, and the method further comprises:

determining, by the one or more computers, that the reference counter number is equal to one, and in response:

requesting, by the one or more computers, removal of a second persistency associated with the second Tenant.

4. The method of claim 1 , wherein the first service provides one or more service instances to one or more applications, the method further comprising:

determining that the first Application uses a first service instance for the Tenant, the first service instance being a service instance of the one or more service instances, wherein providing the subscription of the Tenant to the first Service includes subscribing the Tenant to the first instance of the first service.

5. The method of claim 4 , wherein the Tenant is subscribed to a second service instance different from the first service instance, the second service instance being an instance of the one or more service instances of the first service that the second Application uses, the second Application being different from the first Application.

6. The method of claim 1 , wherein the Tenant is a first Tenant, the persistency is a first persistency, and the subscription is a first subscription to the first Service, the method further comprising:

receiving, from a second Tenant different from the first Tenant, a second request to subscribe to the first Application; and

determining that the second Tenant is new to the first Service, and in response:

creating a second persistency for the second Tenant with respect to the first Service, the second persistency being different from the first persistency,

providing a second subscription of the second Tenant to the first Service and associating the second subscription to the second persistency, and

adding the first Application to the second subscription.

7. A non-transitory, computer-readable medium storing one or more instructions executable by a computer system to perform operations comprising:

receiving a Tenant request to subscribe to a first Application;

determining a first Service that the first Application consumes; and

determining that a Tenant is new to the first Service and in response:

creating a persistency for the Tenant with respect to the first Service,

providing a subscription of the Tenant in the first Service,

associating the subscription to the persistency, and

adding the first Application to the subscription of the Tenant to the first Service;

identifying an already-existing subscription of the Tenant to the first Service; and

providing a second Application to be added to the already-existing subscription of the Tenant to the first Service;

wherein the already-existing subscription is associated with a reference counter counting number of Applications that consume the first Service and are subscribed by the Tenant;

wherein the number on the reference counter is determined by a number of Service OPEN AUTHORIZATION (OAUTH) Clients provided for each Tenant request received from the Tenant to get a respective Application subscription.

8. The non-transitory, computer-readable medium of claim 7 , wherein the Tenant is a first Tenant and the Tenant request is a first request, and the operations further comprise:

receiving from a second Tenant a second request to unsubscribe from a third Application;

determining a second Service associated with the third Application;

determining a reference counter number associated with a second Tenant subscription to the second Service; and

determining that the reference counter number is greater than one, and in response:

requesting removal of the third Application from the second Tenant subscription to the second Service.

9. The non-transitory, computer-readable medium of claim 8 ,

wherein the persistency is a first persistency, and operations further comprise:

one or more instructions executable to perform determining that the reference counter number is equal to one, and in response:

requesting removal of a second persistency associated with the second Tenant.

10. A computer-implemented system, comprising:

one or more computers; and

one or more computer memory devices interoperably coupled with the one or more computers and having tangible, non-transitory, machine-readable media storing one or more instructions that, when executed by the one or more computers, perform operations comprising:

receiving a Tenant request to subscribe to a first Application,

determining a first Service that the first Application consumes, and

determining that a Tenant is new to the first Service, and in response:

creating a persistency for the Tenant with respect to the first Service,

providing a subscription of the Tenant in the first Service,

associating the subscription to the persistency, and

adding the first Application to the subscription of the Tenant to the first Service;

identifying an already-existing subscription of the Tenant to the first Service; and

providing a second Application to be added to the already-existing subscription of the Tenant to the first Service;

wherein the already-existing subscription is associated with a reference counter counting number of Applications that consume the first Service and are subscribed by the Tenant;

wherein the number on the reference counter is determined by a number of Service OPEN AUTHORIZATION (OAUTH) Clients provided for each Tenant request received from the Tenant to get a respective Application subscription.

11. The computer-implemented system of claim 10 , wherein the Tenant is a first Tenant and the Tenant request is a first request, the system being configured to:

receive from a second Tenant a second request to unsubscribe from a third Application;

determine a second Service associated with the third Application;

determine a reference counter number associated with a second Tenant subscription to the second Service; and

determine that the reference counter number is greater than one, and in response:

requesting removal of the third Application from the second Tenant subscription to the second Service and

determine that the reference counter number is equal to one, and in response:

request removal of the second tenant subscription from the second service.