Create HTTP Lookup for CPP Client

[jai1]

In order to do a smooth production roll out we want to bring HTTP Lookup in CPP Client - using libcurl.

[jai1]

Can't use boost::asio since we are using bost 1.41 which doesn't have support for native handle

[jai1]

@saandrews @msb-at-yahoo
I was able to get libcurl (Version 7.19.7) with boost (Version 1.41) using curl_multi_socket_action -
https://github.com/jai1/CPlusPlus-Learn/blob/master/curlExamples/old_curl_asio_without_socket_reuse.cpp

but when I ran it with valgrind I saw memory leaks https://gist.github.com/jai1/950d93198eea07ab5522833b40bfd9f6

I think this is an issue with the old curl library since
a. I saw checked curl github issues where someone complained about similar memory leak and was instructed to use the new library version.
b. I built and linked the code to the latest version curl library - I see no leaks.

So I am going ahead with Matteo's suggestion and creating a thread pool with block curl calls (using easy interface). Let me know if you want me to change the approach.

[msb-at-yahoo]

i suggest you default the thread pool size to 1.

[jai1]

I ran into this issue with libcurl - https://www.redhat.com/archives/libvir-list/2012-October/msg00210.html

#0 0x00007ffff68ab70b in addbyter (output=110, data=0x7fffcabfbca0) at /home/jai1/curl-master/lib/mprintf.c:998
#1 0x00007ffff68aa543 in dprintf_formatf (data=0x7fffcabfbca0, stream=0x7ffff68ab6d2 , format=0x7ffff68ea1e1 "name lookup timed out", ap_save=0x7fffcabfbce0)
at /home/jai1/curl-master/lib/mprintf.c:631
#2 0x00007ffff68ab78b in curl_mvsnprintf (buffer=0x0, maxlength=16384, format=0x7ffff68ea1e1 "name lookup timed out", ap_save=0x7fffcabfbce0) at /home/jai1/curl-master/lib/mprintf.c:1016
#3 0x00007ffff688df85 in Curl_failf (data=0x8bc530, fmt=0x7ffff68ea1e1 "name lookup timed out") at /home/jai1/curl-master/lib/sendf.c:248
#4 0x00007ffff687ec72 in Curl_resolv_timeout (conn=0x7ffff737bf3f, hostname=0x7fffcabfbe20 "@\276\277\312\377\177", port=32767, entry=0x7fffb0019368, timeoutms=140737341013673)
at /home/jai1/curl-master/lib/hostip.c:622
#5 0x00000000008d9b58 in ?? ()
#6 0x00007fffcabfbfd0 in ?? ()

[merlimat]

@jai1 Did you see these tips for libcurl in multi-thread apps?
https://curl.haxx.se/libcurl/c/threadsafe.html

[jai1]

@msb-at-yahoo @merlimat

• Sorry to cause a storm in a teacup, I had not read the document that Matteo sent

The implementation is done and passes the cms-qa tests - can you please review it and give a +1.
#317