Params Layering Support
Params support layering. Layering is performed for the
configs/demo/params folder. Let’s say you have the following params directory structure:
configs/demo/params ├── base.txt ├── development.txt └── production.txt
In this case, you want to define your common params used for templates in the
base.txt and overrides in
production.txt. For example, let’s say we’re setting the min and max size of an autoscaling group. We could have something like this:
Lono will use the
InstanceType=m5.large parameter value when launching the stack with
LONO_ENV=production. Lono will use
InstanceType=t3.micro for all other
LONO_ENV values. Example:
$ lono cfn deploy demo # InstanceType=t3.micro $ LONO_ENV=production lono cfn deploy demo # InstanceType=m5.large
Remember params can be used to affect templates at run-time. Here’s the lifecycle flow to see when the run-time phase happens.
Depending on how you use params with layering, you can dramatically simpify your code.
Note: The parameters layering works similiarly for all location lookups: Params Lookup Locations.
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