GSoC 2014: Lua Scripting Support for Monkey, Week 8

As mentioned in the last post, the week before the last one I was trying to understand event driven programming and monkeys use of epoll to serve large number of connections and had started writing the response part of the plugin and struggled to complete it.This week was also spent on the same task except that I think I have a hold of what am I doing. I have been studying the fast cgi and cgi plugins for figuring out how to deal with writing response back to the client.

The CGI plugin maintains a list of connections and forks to execute the script with a execv and uses two pipes to communicate with the parent and uses epoll for getting notification when it has something to read from the pipe and write back to the client. Similarly fast cgi has it’s own socket for communicating with monkey and uses epoll for notification. In case of the lua plugin, I had a few options to implement it. Till now, I have been executing lua code from the monkeys thread which obviously will prevent the thread from doing anything else. So the solution is to either fork and execute or spawn a new thread.

Currently, there is no particular advantage of using epoll to get notification from the lua thread as I can only start writing to the client socket once the entire lua script finish executing.I am stuck on putting together this small detail and the plugin should be ready in a bare metal state.

Next Week, I will sort out the remaining details for IO also taking into acount chunked encoding and figure out a way to collect some metrics on the execution.

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