Add TTFB for all requests in metrics-v3 in addition to the existing
GetObject. Also for the requests that do not return a body in the
response, calculate TTFB as the HTTP status code and the headers are
sent.
Fix a regression in #19733 where TTFB metrics for all APIs except
GetObject were removed in v2 and v3 metrics. This causes breakage for
existing v2 metrics users. Instead we continue to send TTFB for all APIs
in V2 but only send for GetObject in V3.
Metrics v3 is mainly a reorganization of metrics into smaller groups of
metrics and the removal of internal aggregation of metrics received from
peer nodes in a MinIO cluster.
This change adds the endpoint `/minio/metrics/v3` as the top-level metrics
endpoint and under this, various sub-endpoints are implemented. These
are currently documented in `docs/metrics/v3.md`
The handler will serve metrics at any path
`/minio/metrics/v3/PATH`, as follows:
when PATH is a sub-endpoint listed above => serves the group of
metrics under that path; or when PATH is a (non-empty) parent
directory of the sub-endpoints listed above => serves metrics
from each child sub-endpoint of PATH. otherwise, returns a no
resource found error
All available metrics are listed in the `docs/metrics/v3.md`. More will
be added subsequently.
