Hi,
I am implementing a HTTP server application that utilizes HTTP client in
its generic handler. i.e. on receiving a request it makes several requests
to other servers and after it gets responses back it finalizes original
request. Here is pseudo code of the generic callback:
global_base;
generic_callback() {
url = get_user_data(req);
for (server : remote_servers) {
evcon = evhttp_connection_base_new(global_base, ..);
req = evhttp_request_new(client_request_done, req, url);
evhttp_make_request(evcon, req);
}
}
The code works fine. I've decided to check it for memory leaks using
valgrind and discovered that a lot of memory is lost in
evhttp_connection_base_new().
I believe my code should cleanup the connections I've created.
I checked libevent examples and googled but I did not find how to make this
cleanup properly. All examples show HTTP client with single connection
created in main() function that is cleaned after event_base_dispatch() is
over. But in my case I dynamically create connection and I need to clean it
when it is unused. I was trying to run the evhttp_connection_free()
function in client_request_done callback (the one passed to
evhttp_request_new),
but evhttp_request_get_connection(req) returns NULL. It means the
connection object is not accessible in the callback function. Hmm... How do
I expect to free the connection then?
I see version 2.1 has function evhttp_connection_free_on_completion() but
it still does not help to prevent leaks in evhttp_connection_base_new().
Here is the code that I was trying to profile:
https://github.com/anatol/pacoloco/blob/master/hub.c#L213
And here is the valgrind report ran against current HEAD (a77a82a03f85):
https://gist.github.com/anatol/7a44648af62627da46a4
How to prevent this memory leak in the http client code?
