QQGoblin

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import argparse
import json
import logging
import re
import os
from json.decoder import JSONDecodeError

QQGoblin

class ApiClient(object):

    _API_URL_PREFIX = '/api/v1/namespaces/'

    def __init__(self, bypass_api_service=False):
        self._bypass_api_service = bypass_api_service
        self.pool_manager = urllib3.PoolManager(**k8s_config.pool_config)
        self._base_uri = k8s_config.server
        self._api_servers_cache = [k8s_config.server]
        self._api_servers_cache_updated = 0

QQGoblin

def get_dcs(config):
    # 获取所有DCS实现的名称，dcs_modules()通过pkgutil查询dcs目录下所有python文件的名称
    # 最终返回一个List，内容为：patroni.dcs.kubernetes 等等。
    modules = dcs_modules()

    for module_name in modules:
        name = module_name.split('.')[-1] # dcs名称：如etcd、kubernetes等等
        if name in config:  # 判断配置文件中是否有对应的名称的Section配置段
            try:
                module = importlib.import_module(module_name)

QQGoblin

def _load_cluster(self):
    stop_time = time.time() + self._retry.deadline
    # 刷新kube-apiserver的地址信息
    self._api.refresh_api_servers_cache()
    try:

        with self._condition:
            # 等待podsCache和kindCache的缓存建立完毕
            self._wait_caches(stop_time)
            # 填充集群中的member信息（Pod信息）以及Endpoint信息

QQGoblin

class Patroni(AbstractPatroniDaemon):
  
      def __init__(self, config):

        super(Patroni, self).__init__(config)
        self.version = __version__
        # 通过配置文件中的配置，动态加载dcs的lib，并初始换
        self.dcs = get_dcs(self.config)
        # 初始化watchdog服务，PS：作为容器运行时不需要
        self.watchdog = Watchdog(self.config)

QQGoblin

class Ha(object):
   """
    在DCS上更新Postgresql节点的状态
   """
    def touch_member(self):
        with self._member_state_lock:
            data = {
                'conn_url': self.state_handler.connection_string,
                'api_url': self.patroni.api.connection_string,
                'state': self.state_handler.state,

QQGoblin

class Postgresql(object):
    def stop(self, mode='fast', block_callbacks=False, checkpoint=None,
             on_safepoint=None, on_shutdown=None, stop_timeout=None):
        """Stop PostgreSQL

        Supports a callback when a safepoint is reached. A safepoint is when no user backend can return a successful
        commit to users. Currently this means we wait for user backends to close. But in the future alternate mechanisms
        could be added.

        :param on_safepoint: This callback is called when no user backends are running.

QQGoblin

class Postgresql(object):
    def start(self, timeout=None, task=None, block_callbacks=False, role=None):
        """Start PostgreSQL

        Waits for postmaster to open ports or terminate so pg_isready can be used to check startup completion
        or failure.

        :returns: True if start was initiated and postmaster ports are open, False if start failed"""
        # make sure we close all connections established against
        # the former node, otherwise, we might get a stalled one

QQGoblin

class Ha(object):
    def demote(self, mode):
        """Demote PostgreSQL running as master.

        :param mode: One of offline, graceful or immediate.
            offline is used when connection to DCS is not available.
            graceful is used when failing over to another node due to user request. May only be called running async.
            immediate is used when we determine that we are not suitable for master and want to failover quickly
                without regard for data durability. May only be called synchronously.
            immediate-nolock is used when find out that we have lost the lock to be master. Need to bring down

QQGoblin

class Kubernetes(AbstractDCS):
    def update_leader(self, last_lsn, slots=None):
        # PS：这个是Leader更新Endpoint的接口，没有获取Leader之前，无法更新
        # 获取当前leader对应的ep
        kind = self._kinds.get(self.leader_path)
        kind_annotations = kind and kind.metadata.annotations or {}

        # ep上annotations.leader和当前实例名称不一致，退出
        if kind and kind_annotations.get(self._LEADER) != self._name:
            return False