Utility

ray.util.ActorPool(actors)	Utility class to operate on a fixed pool of actors.
ray.util.queue.Queue([maxsize, actor_options])	A first-in, first-out queue implementation on Ray.
ray.nodes()	Get a list of the nodes in the cluster (for debugging only).
ray.cluster_resources()	Get the current total cluster resources.
ray.available_resources()	Get the current available cluster resources.

Custom Metrics

ray.util.metrics.Counter(name[, ...])	A cumulative metric that is monotonically increasing.
ray.util.metrics.Gauge(name[, description, ...])	Gauges keep the last recorded value and drop everything before.
ray.util.metrics.Histogram(name[, ...])	Tracks the size and number of events in buckets.

Debugging

ray.util.pdb.set_trace([breakpoint_uuid])	Interrupt the flow of the program and drop into the Ray debugger.
ray.util.inspect_serializability(base_obj[, ...])	Identifies what objects are preventing serialization.
ray.timeline([filename])	Return a list of profiling events that can viewed as a timeline.