I've been a user of HttpClient 3 for several years and am now migrating to
using HttpClient 4.
With version 3, I wrapped (extended) the client in order to instrument it (via
JMX). I kept track of the following pieces of information, per host:
-Number of request (socket) timeouts
-Number of connection timeouts
-Number of timeouts while waiting for connection from pool
-Total number of requests
-Average Request duration
-Maximum Request duration
-Number of connections currently in pool
-Max connections in pool
With HttpClient version 4, I'd rather not extend the client and would instead
like have developers use a pre-configured httpclient that was created with a
ThreadSafeClientConnManager.
I can see how to use a HttpRequestInterceptor and HttpResponseInterceptor
to record things like number of transactions, request durations, etc.
What I need help with is determining how I can record timeout information.
When I'd recorded this in the past, I caught exceptions thrown by HttpClient's
execute method in my extended class. It looks like when I call execute on
HttpClient 4, if an exception is thrown, the HttpResponseInterceptor will not
be called. I'm not sure where to intercept in this case.
Another related question: I typically have a scheduled task that occasionally
calls the connection manager's closeIdleConnections method. After I do this,
when I want to learn how many connections are in each pool, I have to have kept
track of each HttpRoute and then call the getConnectionsInPool(route) method
for each route. Is there a way I can have the connection manager give me the
list of routes so I don't have to keep track of them myself?
And one final question: I'd like to consider the possibility of handing out an
HttpClient that will not talk to any host unless it has been explicitly
configured (to force developers to think about the proper max pool size so we
fail fast when a remote source is having issues). What I'm thinking is
something like:
ConnPerRouteBean connPerRoute = new ConnPerRouteBean(0);
// Then explicitly enable hosts as follows
HttpHost localhost = new HttpHost("localhost", 8080);
localhostRoute = new HttpRoute(localhost);
connPerRoute.setMaxForRoute(localhostRoute, 10);
ConnManagerParams.setMaxConnectionsPerRoute(params, connPerRoute);
But I currently get an exception when instantiating ConnPerRouteBean with 0
(needs to be a positive integer). Is there a different way to accomplish this
other than the path I've outlined above?
Thanks - I realize this was long.
Mike
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