Simple system for logging the outputs

Add the following to your wscript file:

def init(ctx):
    ctx.load('build_logs')

waflib/extras/build_logs.py

@@ -0,0 +1,107 @@
+#!/usr/bin/env python
+# encoding: utf-8
+# Thomas Nagy, 2013 (ita)
+
+"""
+A system for recording all outputs to a log file. Just add the following to your wscript file::
+
+  def init(ctx):
+    ctx.load('build_logs')
+"""
+
+import atexit, sys, time, os, shutil, threading
+from waflib import Logs, Context
+
+# adding the logs under the build/ directory will clash with the clean/ command
+try:
+	up = os.path.dirname(Context.g_module.__file__)
+except AttributeError:
+	up = '.'
+LOGFILE = os.path.join(up, 'logs', '%s.log' % time.strftime('%Y_%m_%d_%H_%M'))
+
+wlock = threading.Lock()
+class log_to_file(object):
+	def __init__(self, stream, fileobj, filename):
+		self.stream = stream
+		self.encoding = self.stream.encoding
+		self.fileobj = fileobj
+		self.filename = filename
+		self.is_valid = True
+	def replace_colors(self, data):
+		for x in Logs.colors_lst.values(): 
+			if isinstance(x, str):
+				data = data.replace(x, '')
+		return data
+	def write(self, data):
+		try:
+			wlock.acquire()
+			self.stream.write(data)
+			self.stream.flush()
+			if self.is_valid:
+				self.fileobj.write(self.replace_colors(data))
+		finally:
+			wlock.release()
+	def fileno(self):
+		return self.stream.fileno()
+	def flush(self):
+		self.stream.flush()
+		if self.is_valid:
+			self.fileobj.flush()
+	def isatty(self):
+		return self.stream.isatty()
+
+def init(ctx):
+	global LOGFILE
+	filename = os.path.abspath(LOGFILE)
+	try:
+		os.makedirs(os.path.dirname(os.path.abspath(filename)))
+	except OSError:
+		pass
+
+	if hasattr(os, 'O_NOINHERIT'):
+		fd = os.open(LOGFILE, os.O_CREAT | os.O_TRUNC | os.O_WRONLY | os.O_NOINHERIT)
+		fileobj = os.fdopen(fd, 'w')
+	else:
+		fileobj = open(LOGFILE, 'w')
+	old_stderr = sys.stderr
+
+	# sys.stdout has already been replaced, so __stdout__ will be faster
+	#sys.stdout = log_to_file(sys.stdout, fileobj, filename)
+	#sys.stderr = log_to_file(sys.stderr, fileobj, filename)
+	sys.stdout = log_to_file(sys.__stdout__, fileobj, filename)
+	sys.stderr = log_to_file(sys.__stderr__, fileobj, filename)
+
+	# now mess with the logging module...
+	for x in Logs.log.handlers:
+		try:
+			stream = x.stream
+		except AttributeError:
+			pass
+		else:
+			if id(stream) == id(old_stderr):
+				x.stream = sys.stderr
+
+def exit_cleanup():
+	try:
+		fileobj = sys.stdout.fileobj
+	except AttributeError:
+		pass
+	else:
+		sys.stdout.is_valid = False
+		sys.stderr.is_valid = False
+		fileobj.close()
+		filename = sys.stdout.filename
+
+		Logs.info('Output logged to %r' % filename)
+
+		# then copy the log file to "latest.log" if possible
+		up = os.path.dirname(os.path.abspath(filename))
+		try:
+			shutil.copy(filename, os.path.join(up, 'latest.log'))
+		except OSError:
+			# this may fail on windows due to processes spawned
+			# 
+			pass
+
+atexit.register(exit_cleanup)
+