LongArticleTaskServer/applications/utils/async_apollo_client.py

# -*- coding: utf-8 -*-
import json
import logging
import socket
import asyncio
import aiohttp


class AsyncApolloClient:
    def __init__(
        self,
        app_id,
        cluster="default",
        config_server_url="http://localhost:8080",
        timeout=35,
        ip=None,
    ):
        self.config_server_url = config_server_url
        self.appId = app_id
        self.cluster = cluster
        self.timeout = timeout
        self.stopped = False
        self.ip = ip or self._init_ip()

        self._cache = {}
        self._notification_map = {"application": -1}
        self._stop_event = asyncio.Event()

    def _init_ip(self):
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        try:
            s.connect(("8.8.8.8", 53))
            return s.getsockname()[0]
        finally:
            s.close()

    async def get_value(
        self,
        key,
        default_val=None,
        namespace="application",
        auto_fetch_on_cache_miss=False,
    ):
        if namespace not in self._notification_map:
            self._notification_map[namespace] = -1
            logging.info(f"Add namespace '{namespace}' to local notification map")

        if namespace not in self._cache:
            self._cache[namespace] = {}
            logging.info(f"Add namespace '{namespace}' to local cache")
            await self._long_poll()

        if key in self._cache[namespace]:
            return self._cache[namespace][key]
        elif auto_fetch_on_cache_miss:
            return await self._cached_http_get(key, default_val, namespace)
        else:
            return default_val

    async def start(self):
        if len(self._cache) == 0:
            await self._long_poll()
        asyncio.create_task(self._listener())

    async def stop(self):
        logging.info("Stopping listener...")
        self._stop_event.set()

    async def _cached_http_get(self, key, default_val, namespace="application"):
        url = f"{self.config_server_url}/configfiles/json/{self.appId}/{self.cluster}/{namespace}?ip={self.ip}"
        async with aiohttp.ClientSession() as session:
            async with session.get(url) as r:
                if r.status == 200:
                    data = await r.json()
                    self._cache[namespace] = data
                    logging.info(f"Updated local cache for namespace {namespace}")
                else:
                    data = self._cache.get(namespace, {})

        return data.get(key, default_val)

    async def _uncached_http_get(self, namespace="application"):
        url = f"{self.config_server_url}/configs/{self.appId}/{self.cluster}/{namespace}?ip={self.ip}"
        async with aiohttp.ClientSession() as session:
            async with session.get(url) as r:
                if r.status == 200:
                    data = await r.json()
                    self._cache[namespace] = data["configurations"]
                    logging.info(
                        f"Updated local cache for namespace {namespace} release key {data['releaseKey']}"
                    )

    async def _long_poll(self):
        url = f"{self.config_server_url}/notifications/v2"
        notifications = [
            {"namespaceName": k, "notificationId": v}
            for k, v in self._notification_map.items()
        ]
        params = {
            "appId": self.appId,
            "cluster": self.cluster,
            "notifications": json.dumps(notifications, ensure_ascii=False),
        }

        try:
            async with aiohttp.ClientSession() as session:
                async with session.get(url, params=params, timeout=self.timeout) as r:
                    if r.status == 304:
                        logging.debug("No change.")
                        return
                    if r.status == 200:
                        data = await r.json()
                        for entry in data:
                            ns = entry["namespaceName"]
                            nid = entry["notificationId"]
                            logging.info(f"{ns} has changes: notificationId={nid}")
                            await self._uncached_http_get(ns)
                            self._notification_map[ns] = nid
                    else:
                        logging.warning("Sleep due to unexpected status...")
                        await asyncio.sleep(self.timeout)
        except Exception as e:
            logging.warning(f"Error during long poll: {e}")
            await asyncio.sleep(self.timeout)

    async def _listener(self):
        logging.info("Entering listener loop...")
        while not self._stop_event.is_set():
            await self._long_poll()
        logging.info("Listener stopped.")
        self.stopped = True