Shared value resolution with multiple runtime containers

Policies and services facilitate sharing values between composition containers in an extensible application environment. A value resolver service receives a request from a value resolver which has a value resolution policy. The service identifies other value resolvers which have compatible policies, queries them consistent with the policies involved, obtains values, and supplies them to the requesting value resolver. The value resolution policy specifies an order for searching composition containers, and a visibility for sharing values between composition containers during value resolution; policies may depend on composition container scope. If value resolvers cannot provide values, the value resolver service invokes fault handlers.