1. A method comprising: within a logical composition stage, selecting a set of first workflows for a web service from a plurality of first workflows generated for the web service; within a physical composition stage, selecting a set of second workflows from a plurality of second workflows generated based at least on the set of first workflows selected within the logical composition stage; within the runtime stage, selecting a third workflow to be executed from the set of second workflows and that satisfies specified requirements; within an execution environment, executing the third workflow selected, as execution of the web service; and, periodically dynamically assessing and reselecting the third workflow selected within the runtime stage, the set of second workflows selected within the physical composition stage, and the set of first workflows selected within the logical composition stage.