brokers_per_zone instead of number_of_broker_nodes

[joaoestrela]

What

• Replace variable number_of_broker_nodes with broker_per_zone
• Default broker_per_zone as 1
• Validation on subnet_ids variable, should not be empty.

Why

• instead of relying on the input being a multiple of the subnets we can calculate the number_of_broker_nodes by multiplying the desired number of brokers per zone per subnets
• this behaviour is similar to the AWS Console UI approach (custom method) that requires the number of brokers per zone and subnets
• number of brokers per zone is a more understandable variable than number of broker of nodes

[aknysh]

/test all

[joaoestrela]

Sorry, didn't test it all through, feel free to run the tests in now

[aknysh]

/test all

[aknysh]

@Evilong thanks for the PR

Please address https://github.com/cloudposse/actions/runs/7863863551?check_suite_focus=true

Error: Invalid value for variable
        	            	
        	            	  on main.tf line 39, in module "kafka":
        	            	  39:   subnet_ids           = module.subnets.private_subnet_ids
        	            	
        	            	The subnet_ids list must have at atleast 1 value.

we have 2 tests: when the module is enabled and disabled.
when the module is disabled, module.subnets.private_subnet_ids is an empty list, but the new validation fails b/c of that.

maybe just add

subnet_ids             = module.this.enabled ? module.subnets.private_subnet_ids : [""]

This Pull Request has been updated, so we're dismissing all reviews.

[joaoestrela]

That might do it.
The validation is actually working as intended not allowing empty list, but since this is a test that you want to I don't see a problem with the suggested workaround.

[aknysh]

/test all