Query - how to report on number of connections in pool to upstream?

[xushichangdesmond]

Hi

It doesnt appear to me at least, that there is any way to get at internal pingora metrics including the number of connections in the pool. Is there any way to do this?

[xushichangdesmond]

or could we implement an optional trait for the proxy to receive pool connection callbacks for push/pop?

[eaufavor]

We might have the solution in place already depending on the exact problems to solve. What problems are we trying to solve here?

[xushichangdesmond]

So my upstream service has a soft limit on number of connections say 20000 on each upstream peer node, and I would like to be able to keep track of the number of connections open by the proxy to each upstream peer, reporting it as a metric every minute or so. Ideally I would have the number of inflight connections to each peer as well as number of connections idling in the pool for each peer. Currently i am able to keep track of number of inflight connections using the ProxyHttp trait, but I am unable to keep track of number of connections idling in the pool. Note too that this is a separate want from upstream_keepalive_pool_size configuration option. Here, all I want is to be able to determine number of open connections, not to limit it yet.

Thank you.

[eaufavor]

Excellent! That was something I expected.

So when you try to connect to your upstream with HttpPeer, you can put a Tracer object into it. The tracer itself can hold a Arc<AtomicUsize>. The tracing evens will be called whenever a connection is created and disconnected. From there you can access the real time number of connections (both active and in the pool idling) via a copy of the Arc<AtomicUsize>.

[xushichangdesmond]

sounds good. many thanks.