What is the best way to expose a timestamp from your application?

The correct way to expose a timestamp from an application in Prometheus is to use agauge metricwhere thetimestamp value(in Unix time, seconds since epoch) is stored as the metric’svalue. This approach aligns with the Prometheus data model, which discourages embedding timestamps as labels or metadata.

Example:

app_last_successful_backup_timestamp_seconds 1.696358e+09

In this example, the gauge represents the timestamp of the last successful backup. The _seconds suffix indicates the unit of measurement, making the metric self-descriptive. Prometheus automatically assigns timestamps to scraped samples, so the metric’s value is treated purely as data, not as a Prometheus sample time.

Options B and D are incorrect because Prometheus does not allow arbitrary timestamps or labels for time values. Option C is incorrect since counters are monotonically increasing and not suited for discrete timestamp values.