Create a /stats endpoint for VSecM Safe

[v0lkan]

VSecM Safe shall have a /stats endpoint.

The endpoint will show overall system stats; how many workloads are there; TTL of secrets, whether any of the secrets are about to expire etc.

Some details:

• stats endpoint will provide stats like total number of secrets, names of the secrets that are about to expire (those that passed their half-life), the current load of the internal queues (what is the capacity, and len of the queue), last time someone or something has established a successful connection to VSecM Safe, whether it can still talk to the SPIRE workload API.
• stats can also check and report the current state of SPIRE server’s and SPIRE agent’s health endpoints. (though, we might later move that feature to a /health endpoint too.
• We would be able to call this from VSecM Sentinel.
• Stats endpoint will cache its findings regularly (i.e. constantly calling /stats will not result in querying the system all the time; stats will just return the last snappshotted statistics – that is a tradeoff between accuracy and performance; the cache interval shall be configurable)

[muratmirgun]

Can I take this issue?

[v0lkan]

It’s all yours — I’ll add some more details to the description.