Abstract: A computing infrastructure configuration system and method include an infrastructure-as-code configuration tool providing a configuration language that defines the configuration and operation of the computing infrastructure using a declarative syntax. The declarative syntax is configured to express a plurality of built-in functions that can be executed by the computing infrastructure based on the configuration of the computing infrastructure. The system and method further include a syntax extension from the declarative syntax that expresses one or more provider-defined functions defined by one or more providers, and connected to the configuration tool by a provider protocol, the provider protocol providing the syntax extension to invoke the one or more provider-defined functions via the configuration language to enable the computing infrastructure to call at least one of the one or more of the provider-defined functions for execution by the computing infrastructure.