1. A method for managing configurable resource policies, the method comprising: receiving, by one or more processors, a user selection; executing, by one or more processors, a resource expression associated with the received user selection to extract information from an executing simulation, wherein the executing simulation is executing in a computer system, wherein executing, by one or more processors, the resource expression associated with the received user selection to extract information from the executing simulation comprises: executing, by one or more processors, the resource expression to determine a resource requirement at run-time associated with a task to determine respective resource requirements using existing conditions at a current point in the executing simulation, wherein resource requirement parameters determined by the resource expressions include parameters comprising types and identities of the resources required; a quantity in a form of an absolute quantity, a maximum available quantity or a maximum affordable quantity; time constraints specifying a resource availability within a given time interval; and an allocation using one of a static allocation or a dynamic generation of resources, wherein the resource requirement parameters are specified in an application programming interface (API) call received over a network by a client from a server; determining, by one or more processors, whether there are more user selections to process; in response to a determination that there are no more user selections to process, selecting a set of rules using the user selections and resource expression, wherein selecting the set of rules using the user selections comprises: selecting, by one or more processors, the set of rules from a group of rules, wherein the group of rules is matched to: a resource pool; a re-use strategy, in which re-use of a resource is based on a selected one of a most-recently-used, a most-frequently-used, or a user predefined re-use method; a cost and quantity defining a selected one of a fixed quantity, a maximum quantity affordable and a maximum quantity available; an affinity defining how to allocate resources to a group of tasks; a priority, assigned to tasks for determining which task has precedence in the event of simultaneous requests; and atomicity defining whether to permit preemption of resources allocated to a task in the event of higher priority task requirements; populating, by one or more processors, a resource template using extracted information and selected rules; generating, by one or more processors, a resource policy using the populated template; and modifying a behavior of the executing simulation and modifying the computer system on which the executing simulation is running by allocating and de-allocating, by one or more processors, resources from the resources pool to the computer system for use in performing the task in the executing simulation based on the generated resource policy.