Q client for Bloomberg

Marshall Wace has kindly contributed a Linux-based Bloomberg Feed Handler, written by Sufian Al-Qasem & Attila Vrabecz, using the Bloomberg Open Api.

Design notes

Bloomberg uses an event-driven model whereby they push EVENT objects to consumers – SUMMARY, TRADE and QUOTE. The C code in bloomberg.c handles the connectivity to the Bloomberg appliance (hosted on client’s site) and also does the conversion from an EVENT object to a dictionary (Bloomberg mnemonic <> Value pair) which is then processed on the q main thread via the following:

Update:{@[value;x;-1“Update: '”,string[x 0]," ",]}

The Bloomberg API calls back on a separate thread and copies a pointer to that object onto a lock-free queue; eventfd is then used to create a K struct (a dictionary representation of the EVENT) on the q main thread and process. A function is defined for every EVENT type (Authorize/SessionStarted/MarketDataEvent/etc …) which carries out the desired behaviour in q.

Tested with Bloomberg Open API and Uses http://www.liblfds.org