socketscience.py

import time
import random
import msgpack
import regex
import chatcommunicate
from globalvars import GlobalVars
from helpers import log
from tasks import Tasks


class SocketScience:
    _incomplete_messages = {}
    _pings = []
    _switch_task = None

    @staticmethod
    def send(payload):
        encoded = msgpack.dumps(payload)

        # Messages can be 500 chars, but we need to leave space for control and message ident
        chunks = [encoded[i:i + 485] for i in range(0, len(encoded), 485)]
        message_id = random.randint(1000, 9999)

        chunks[0] = "\u0002" + str(message_id) + chunks[0]
        chunks[-1] = chunks[-1] + str(message_id) + "\u0003"
        for n in range(1, len(chunks) - 1):
            chunks[n] = "\u0016" + str(message_id) + chunks[n]

        for chunk in chunks:
            chatcommunicate.tell_rooms_with("direct", chunk)

    @staticmethod
    def receive(content):
        global _incomplete_messages

        content = content.strip()

        # U+0002 STX START OF TEXT; U+0003 ETX END OF TEXT; U+0016 SYN SYNCHRONOUS IDLE
        if content.startswith("\u0002") and content.endswith("\u0003"):
            decoded = msgpack.loads(regex.sub(r"\d{4}\u0003", "", regex.sub(r"^\u0002\d{4}", "", content)))
            SocketScience.handle(decoded)

        # STX indicates probably valid, but incomplete - wait for another message with content and ETX.
        elif content.startswith("\u0002") and not content.endswith("\u0003"):
            message_id = regex.match(r"^\u0002(\d{4})", content)[1]
            _incomplete_messages[message_id] = content

        # No STX but ends with ETX, so probably a completion of a previous message.
        elif not content.startswith("\u0002") and content.endswith("\u0003"):
            message_id = regex.match(r"(\d{4})\u0003$", content)[1]
            complete = _incomplete_messages[message_id] + content
            decoded = msgpack.loads(regex.sub(r"\d{4}\u0003", "", regex.sub(r"^\u0002\d{4}", "", complete)))
            SocketScience.handle(decoded)

        # Starts with SYN and message ID - continuation but not completion of previous message.
        elif content.startswith("\u0016"):
            message_id = regex.match(r"^\u0016(\d{4})", content)[1]
            _incomplete_messages[message_id] += regex.sub(r"^\u0016\d{4}", "", content)

        else:
            log('debug', 'SocketScience received malformed direct message')
            log('debug', content)

    @staticmethod
    def handle(content):
        global _pings
        global _switch_task

        if "metasmoke_state" in content:
            if content["metasmoke_state"] == "down":
                log('info', "{} says metasmoke is down, switching to active ping monitoring."
                            .format(content["location"]))
                GlobalVars.metasmoke_down = True
                Tasks.later(SocketScience.check_recent_pings, after=90)

            if content["metasmoke_state"] == "up":
                log('info', '{} says metasmoke is up, disabling ping monitoring.'.format(content["location"]))
                GlobalVars.metasmoke_down = False

        if "ping" in content:
            _pings.append({"timestamp": content["ping"], "location": content["location"]})
            if _switch_task is not None:
                _switch_task.cancel()

    @staticmethod
    def check_recent_pings():
        global _pings
        global _switch_task

        recent = _pings.sort(key=lambda p: p["timestamp"]).reverse()
        if len(recent) >= 1:
            most_recent = recent[0]["timestamp"]
            now = time.time()

        if now - most_recent >= 90 or len(recent) == 0:
            # No active Smokeys. Wait a random number of seconds, then switch to active.
            sleep = random.randint(0, 30)
            _switch_task = Tasks.later(SocketScience.switch_to_active, after=sleep)

    @staticmethod
    def switch_to_active():
        GlobalVars.standby_mode = False
        chatcommunicate.tell_rooms_with("debug", GlobalVars.location + " entering autonomous failover.",
                                        notify_site="/failover")