A method for collecting, aggregating, and composing metrics and a computer system comprises a producer application adapted to periodically generate metrics comprising state information of the producer application; a metric engine adapted to aggregate the metrics; and a consumer application adapted to receive the aggregated metrics, wherein the metric engine is further adapted to produce new metrics in accordance with desired requirements of the consumer application. The computer system further comprises a metric service policy adapted to provide definitions of the metrics generated from the producer application and desired requirements of the consumer application, wherein the metric service policy is adapted to establish an executable set of actions for producing the new metrics from the generated metrics, wherein the metric service policy is adapted to be executable by the metric engine, and wherein multiple metric service policies are simultaneously executable by the metric engine.