Policy Resolution

How policies are resolved and applied in Metric Engine.

Policy Hierarchy

Context Policy: Currently active policy context
Thread Policy: Thread-local policy settings
Global Policy: System-wide default policy
Built-in Policy: Framework default behavior

Resolution Algorithm

def resolve_policy():
    return (
        get_context_policy() or
        get_thread_policy() or
        get_global_policy() or
        get_builtin_policy()
    )

Policy Inheritance

Child contexts inherit parent policies
Explicit settings override inherited values
Null policies fall back to parent

Performance Considerations

Policy resolution is cached per calculation
Context switches invalidate cache
Minimal overhead in hot paths