Multitenant Spring Data JPA with EclipseLink on SAP HANA Cloud Platform

Just a quick post here today, and hopefully I flesh out a more detailed post on SCN later:

OEM model

There are probably two ways to make money developing apps on the HANA Cloud Platform:

1) be incredibly good at it, such that you can build truly awesome stuff that customers aren’t going to care about platform costs and still pay you bucket-loads

2) use the OEM model and build very efficient apps that solve a little problem for lots of people. Keep costs low, and sell to lots and lots of people.

3) be big consult, wine & dine the people with the money, put loadsa people on simple projects bill lots.

I’m aiming for a mix of 1 and 2 to just get into the sweet spot, of course that’s hard work. But this evening I made a step in the right direction by enabling multi-tenant access to one of my apps that auto-magically put the tenant key in all DB accesses in my app – without me having to do any work to specifically write that into the queries.

for reference the magic happens with a custom implementation/extension of JpaRepositoryFactory, JpaRepositoryFactoryBean and SimpleJpaRepository and one line in my Spring xml:

<jpa:repositories base-package=”com.wombling.blah.blah.dao ”
factory-class=”com.wombling.blah.blah.multitenancy.MultiTenantJpaRepositoryFactoryBean” />

my custom tenancy resolver:

public class CurrentTenantResolverImpl implements CurrentTenantResolver<String> {

	@Override
	public String getCurrentTenantId() {

		InitialContext ctx;
		try {
			ctx = new InitialContext();

			Context envCtx = (Context) ctx.lookup("java:comp/env");
			TenantContext tenantContext = (TenantContext) envCtx.lookup("TenantContext");

			return tenantContext.getTenantId();
		} catch (NamingException e) {
			return "NOT_CURRENTLY_RUNNING_MULTI_-_TENANT"; // 36 chars as per real tenant id
		}
	}

}

is called each time a DB query is made (which is already pretty invisible due to “magic” of Spring data and JPA.)

I have to give a huge shout out to   from Slovakia who posted up most of the code I reused. Thanks dude!

http://codecrafters.blogspot.sk/2013/03/multi-tenant-cloud-applications-with.html

I’ll get back to you with some more HR type stuff later.

 

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