According toPrometheus metric naming conventions, a metric name must clearly describewhat is being measuredand include aunit suffixthat specifies the base unit of measurement, following SI standards. For durations, the suffix _seconds is mandatory.
Therefore, the correct and standards-compliant name for a metric tracking HTTP request duration is:
http_request_duration_seconds
This name communicates:
http_request→ the subject being measured (HTTP requests),
duration→ the aspect being measured (the latency or time taken),
_seconds→ the unit of measurement (seconds).
This metric name typically corresponds to ahistogram or summary, exposing submetrics such as _count, _sum, and _bucket. These represent the number of observations, total duration, and distribution across time buckets respectively.
Options A, B, and C fail to fully comply with Prometheus naming standards — they either omit the http_ prefix, use invalid separators (dots), or lack the required unit suffix.
[References:Verified from Prometheus documentation –Metric and Label Naming Conventions,Instrumentation Best Practices, andHistogram and Summary Metric Naming Patterns., ]
