5

import select

     6

    14

    def __init__ (self, source, parser, poll=None) :

    17

    18

                source          - file-like object with poll() and iter()

    19

                parser          - process() bytes -> messages

    20

                poll            - using given polling style:

    21

                    True            - select() source

    22

                    float           - given interval

    23

                    None/False      - single-shot

    29

        self._poll = poll

    37

        for item in self.parser(self.source) :

    39

    40

    def poll (self, timeout=None) :

    41

        """

    42

            Poll source for input, with given timeout in seconds (float).

    43

    44

            A timeout of None indicates to block forever, False indicates to never block.

    45

    46

            Returns True if we have input waiting, False on timeout with no input. None on indeterminate.

    47

        """

    48

    49

        read = write = ()

    50

    51

        if timeout is True :

    52

            timeout = None

    53

            read += (self.source, )

    54

    55

        elif timeout is False :

    56

            timeout = 0.0

    57

    58

        log.debug("%f", timeout)

    59

    60

        # select

    61

        read, write, ex = select.select(read, write, [], timeout)

    62

    63

        if read :

    64

            return True

    65

    66

        else :

    67

            # timeout

    68

            return False

    69

    70

    def loop (self) :

    71

        """

    72

            Continuously read items from syslog source, blocking as suitable.

    73

    74

            Returns once no more lines are available.

    75

    76

            XXX: reconnect?

    77

        """

    78

    79

        # mainloop

    80

        while True :

    81

            # pull in messages

    82

            for item in self :

    83

                yield item

    85

            # poll

    86

            if self._poll :

    87

                # wait

    88

                self.poll(self._poll)

    89

            else :

    90

                # done

    91

                break

    92

    93

            log.debug("tick")

    94

    95

        log.debug("exit")

    96

    97

    def stop (self) :

    98

        """

    99

            Stop loop after current iteration.

   100

        """

   101

   102

        self._poll = False

   103

   104

    def main (self) :

   105

        """

   106

            Mainloop.

   107

        """

   108

   109

        # TODO: SIGINT -> stop()

   110

        return loop()