Threads with independant IO streams

[Alex Martelli]

Jason Harper wrote:

> Is it possible for multiple Python threads to have their own sys.stdout
> (and other streams), such that plain `print' statements in each thread
> send output to different places?
> 
> I have managed to create a separate sys module for each thread (using an
> import hook much like rexec uses), and can have sys.stdout.write()
> output go to different places, but print output still goes to the stdout
> defined in the 'real' sys module.

So, the solution might be to use as "the" sys.stdout a clever class
that does the demuxing you're looking for, e.g.:


import sys, threading

class PerThreadOutput(object):

    def __init__(self):
        self.baseout = sys.stdout
        self.ptout = {}
        sys.stdout = self

    def setOut(self, threadName, stream):
        self.ptout[threadName] = stream

    def write(self, data):
        ctname = threading.currentThread().getName()
        stream = self.ptout.get(ctname, self.baseout)
        stream.write(data)

PerThreadOutput()


You'll need to add locking to taste, and a similarly clever hack to
have softspace be also per-thread (via a property, for example), but
I hope the general idea can help you.


Alex