Monitor Client Connection Pool

[agaengel]

Is it possible to monitor the connection pool of a resteasy client?

[jamezp]

What do you mean by monitor it? What container are you running in?

[agaengel]

We use resteasy with spring. Other pools like org.apache.commons.dbcp2 or org.apache.commons.pool2 are monitored via jmx-exporter and prometheus.

Is there some way to expose the stats of the PoolingHttpClientConnectionManager ?

[jamezp]

It doesn't look like it. It's set in the builder and it doesn't look like there is a way to set it.

resteasy/resteasy-client/src/main/java/org/jboss/resteasy/client/jaxrs/engines/ClientHttpEngineBuilder43.java

Lines 160 to 173 in 58307d8

	HttpClientConnectionManager cm = null;
	if (that.getConnectionPoolSize() > 0) {
	PoolingHttpClientConnectionManager tcm = new PoolingHttpClientConnectionManager(
	registry, null, null, null, that.getConnectionTTL(TimeUnit.MILLISECONDS), TimeUnit.MILLISECONDS);
	tcm.setMaxTotal(that.getConnectionPoolSize());
	if (that.getMaxPooledPerRoute() == 0) {
	that.maxPooledPerRoute(that.getConnectionPoolSize());
	}
	tcm.setDefaultMaxPerRoute(that.getMaxPooledPerRoute());
	cm = tcm;
	} else {
	cm = new BasicHttpClientConnectionManager(registry);
	}

[agaengel]

yes the current version does not provide access to this but would it be a good idea to extend ClientHttpEngine to provide this in general.

I this is a general interest for resteasy I could try to create a PR for this

[jamezp]

It's possible we could do something where we attempt to look it up as a provider or in the configuration of the client, but we can't really add a new method as it's implementation specific. The Apache HTTP Client will likely not be the default client in future releases.

[agaengel]

hi @jamezp what is the plan for the next default client?

will this client support pooling?

[jamezp]

Hi @agaengel, there is no definite plan as of yet. I've experimented with using the Java HTTP Client. There are some issues using it as the Jakarta REST Client Builder allows a HostnameVerifier to be set which is not supported on the client.

We may end up using that or a completely different client. I do need to make a plan for this as I feel HTTP/2 support is critical.