Add MutexableThreadPoolServer and ProcessPoolServer
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Key: THRIFT-1312
URL: https://issues.apache.org/jira/browse/THRIFT-1312
Project: Thrift
Issue Type: New Feature
Components: Ruby - Library
Affects Versions: 0.7
Reporter: Scott Gonyea
Fix For: 0.8, 0.7
Hi, this feature request adds the verbosely-named "MutexableThreadPoolServer"
and "ProcessPoolServer" to the Thrift Ruby Library.
The MutexableThreadPoolServer (MTPServer) contains a thorough set of tests, as
well as an example file that demonstrates its use.
Below is a lengthy description of how we make use of the MTPServer. But before
getting into that, you can find the code here, or in the included patch.
https://github.com/sgonyea/thrift/tree/mtps/lib/rb
This draws very heavily from the ThreadPoolServer, except that it introduces
the use of Mutexes as one way to stop the server from spawning threads.
Further, it offers a #stop_threads method, that will check the state of each
thread and release control once all threads have finished serving requests to
clients.
Internally, this MTPServer is used in conjunction with HAProxy to shut down and
start up, cleanly, and to avoid all sorts of crazy race conditions that often
arise when serving over a raw socket.
When the MTPServer is started, it will fill the ThreadPool with N threads.
Once done, it is ready to receive requests and will yield to a callback if one
is supplied. In this callback, we call out to HAProxy and signal that we are
ready to begin accepting connections from API clients.
The parent application can be setup to trap any signals, as we do, and to then
lock the mutex (to prevent new threads from pooling). It then calls
@server.stop_threads. It also spins off another thread that will hard shut
down the server if Threads continue past an arbitrary amount of time.
The other benefit in using HAProxy is that it will close connections from
clients, if they are idle for some period of time. This prevents another
common issue, where a client remains connected and causes our Thread to block,
until the sun explodes.
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