apiserver_request_duration_seconds does not take into account the
time a request spends in the server filters. If a filter takes longer
then the latency incurred will not be reflected in the apiserver
latency metrics.
For example, the amount of time a request spends in priority and
fairness machineries or in shuffle queues will not be accounted for.
- Add a server filter that attaches request received timestamp to the
request context very early in in the handler chain (as soon as
net/http hands over control to us).
- Use the above received timestamp in the apiserver latency metrics
apiserver_request_duration_seconds.
- Use the above received timestamp in the audit layer to set
RequestReceivedTimestamp.
Kubernetes-commit: d74ab9e1a4929be208d4529fd12b76d3fcd5d546