tree 11622ffb81396c3a87fcc18825bf0abd1bdc5652
parent 1106333af4a5b566d8b3686b3438ddebc75b1b5d
author Sunitha Harish <sunithaharish04@gmail.com> 1613722111 +0530
committer Ed Tanous <ed@tanous.net> 1633024963 +0000

EventService : Fix retry handling for http-client

When the event send/receive is failed, the bmcweb does not handle
the failure to tear-down the complete connection and start a fresh

The keep-alive header from the event listener is read to update
the connection states, so that the connection will be kept alive
or closed as per the subscriber's specifications

Updated the connection state machine to handle retry logic properly.
Avoided multiple simultaneous async calls which crashes the bmcweb. So
added few "InProgress" flags which protects simultaneous async calls.

Changed buffer type from flat_buffer to flat_static_buffer and
imposed an upper limit on total size avoiding heap allocations.
Also changed the requestDataQueue from std::queue to
circular_buffer_space_optimized which allocates memory as needed
and dynamically controls size.

Used boost http response parser as parser for producing the response
message. Set the parser skip option to handle the empty response message
from listening server. On reception of response, the response code in
the header is checked to determine success/failure and trigger retry
in the case of failure.

Tested by:
  - Subscribe for the events at BMC using DMTF event listener
  - Generate an event and see the same is received at the listener's console
  - Update the listner to change the keep-alive to true/false and
    observe the http-client connection states at bmcweb
  - Changed listener client to return non success HTTP status code
    and observed retry logic gets trigrred in http-client.
  - Gave wrong fqdn and observed async resolve failure and retry logc.
  - Stopped listener after connect and verified timeouts on http-client
    side.

Change-Id: Ibb45691f139916ba2954da37beda9d4f91c7cef3
Signed-off-by: Sunitha Harish <sunithaharish04@gmail.com>
Signed-off-by: AppaRao Puli <apparao.puli@linux.intel.com>
Signed-off-by: P Dheeraj Srujan Kumar <p.dheeraj.srujan.kumar@intel.com>