We describe the Active Grid Information Server for performing expressive resource discovery searches and resource management in a grid environment. We represent server meta-data, such as their CPU power, storage capacity and bandwidth as points in a multi-dimensional space and then express queries as predicates over these points. The design of the system is driven by its application as a part of the information infrastructure for computational grids. Such grids provide an infrastructure for sharing computing resources; an information infrastructure is their inherent part which collects resource data and provides search functionality. Our approach complements current solutions such as MDS by adding Event Condition Action rules and an ability to efficiently handle dynamic attributes. An Event Condition Action rule-based system can support ad hoc, adaptive, flexible, and dynamic schedulers that are modifiable at runtime. We evaluate our Active Grid Information Server by evaluating Event Condition Action rules for termination, confluence, and conflict.