Gauges

A gauge is a value that is sampled at some point in time. Typical examples for gauges would be the size of a queue or number of threads in a running state. Since gauges are not updated inline when a state change occurs, there is no information about what might have occurred between samples.

Consider monitoring the behavior of a queue of tasks. If the data is being collected once a minute, then a gauge for the size will show the size when it was sampled. The size may have been much higher or lower at some point during interval, but that is not known.

Call set() with a value:

from spectator import GlobalRegistry

GlobalRegistry.gauge("server.queueSize").set(10)

Gauges will report the last set value for 15 minutes. This done so that updates to the values do not need to be collected on a tight 1-minute schedule to ensure that Atlas shows unbroken lines in graphs. A custom TTL may be configured for gauges. SpectatorD enforces a minimum TTL of 5 seconds.

from spectator import GlobalRegistry

GlobalRegistry.gauge("server.queueSize", ttl_seconds=120).set(10)