Wrap stdout to add timestamps

stdout_wrapper.py

n = datetime.datetime.now

class Wrapper(object):
    def __init__(self, out, severity):
        self.out = out
        self.severity = severity
        self.remaining = None
        self.remaining_ts = None

    def _write(self, t, line):
        print("{0} {1} {2}".format(t, self.severity, line), file=self.out)

    def write(self, s):
        if not s:
            return
        t = n().strftime('%Y-%m-%d %H:%M:%S.%f')
        lines = s.split('\n')  # guaranteed to be non-empty
        last = lines.pop()
        if not lines:
            if self.remaining is not None:
                self.remaining += last
            else:
                self.remaining = last
                self.remaining_ts = t
            return
        if self.remaining is not None:
            self._write(self.remaining_ts, self.remaining + lines.pop(0))
            self.remaining = self.remaining_ts = None
        if last:
            self.remaining = last
            self.remaining_ts = t
        for line in lines:
            self._write(t, line)

    def close(self):
        if self.remaining:
            self._write(self.remaining_ts, self.remaining)
        self.out.close()

    def __del__(self):
        self.close()