‘CMRESHandler‘ object has no attribute ‘_timer‘，socket.gaierror: [Errno 8] nodename nor servname pro

1 错误重现

在Mac上调用Python的CMRESHandler进行elasticsearch的日志写入时，遇到如下错误。一开始还以为是自己的语法出现了错误，排查出发现问题出在库中的代码上。在网上找了一圈都没有发现解决方案，遂记录一下，方便以后他人查找。

解决问题后，成功写入es：

2 解决

出现问题的原因，是库中下面的语句获取ip时，出现了错误（报错地方socket.gethostbyname(socket.gethostname())）。

        self.es_additional_fields.update({
    'host': socket.gethostname(),
                                          'host_ip': socket.gethostbyname(socket.gethostname())})

由于我们不能去修改库中的代码，因此我们只能把库中的代码单独提取出来，然后修改出错的地方，再单独引入这个文件。

修改的后handlers.py文件如下（其他关联的文件也一并的放到了该文件中）：

修改的地方为使用get_local_ip()函数，来代替报错的socket.gethostbyname(socket.gethostname())。
️：这里使用的elasticsearch版本为7.9.1，需要8以下的版本，不然会出现RequestsHttpConnection库找不到的错误（pip3 install "elasticsearch==7.9.1 -i https://pypi.tuna.tsinghua.edu.cn/simple"）。

#!/usr/bin/env python3

# 链接和初始化elasticsearch

import logging
import datetime
import socket
from threading import Timer, Lock
from enum import Enum
from elasticsearch import helpers as eshelpers
from elasticsearch import Elasticsearch, RequestsHttpConnection


# from CMRESSerializer import CMRESSerializer
# from getLocal_ip import get_local_ip
# import settings

from elasticsearch.serializer import JSONSerializer



class CMRESSerializer(JSONSerializer):
    def default(self, data):
        try:
            return super(CMRESSerializer, self).default(data)
        except TypeError:
            return str(data)


def get_local_ip():
    """ 获取本地IP :return: """

    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.connect(('8.8.8.8', 80))
        ip = s.getsockname()[0]
    except Exception as e:
        print(e)
        return ''
    else:
        return ip



class CMRESHandler(logging.Handler):
    """ Elasticsearch log handler """

    class AuthType(Enum):
        """ Authentication types supported The handler supports - No authentication - Basic authentication """
        NO_AUTH = 0
        BASIC_AUTH = 1
        DEVOPS_AUTH = 2

    class IndexNameFrequency(Enum):
        """ Index type supported the handler supports - Daily indices - Weekly indices - Monthly indices - Year indices """
        DAILY = 0
        WEEKLY = 1
        MONTHLY = 2
        YEARLY = 3

    # Defaults for the class
    __DEFAULT_ELASTICSEARCH_HOST = [{
    'host': '10.97.138.194', 'port': 9200}]
    __DEFAULT_AUTH_USER = 'elastic'
    __DEFAULT_AUTH_PASSWD = '[email protected]'

    __DEFAULT_USE_SSL = False
    __DEFAULT_VERIFY_SSL = True
    __DEFAULT_AUTH_TYPE = AuthType.NO_AUTH
    __DEFAULT_INDEX_FREQUENCY = IndexNameFrequency.DAILY
    __DEFAULT_BUFFER_SIZE = 1000
    __DEFAULT_FLUSH_FREQ_INSEC = 1
    __DEFAULT_ADDITIONAL_FIELDS = {
    }
    __DEFAULT_ES_INDEX_NAME = 'python_logger'
    __DEFAULT_ES_DOC_TYPE = '_doc'
    __DEFAULT_RAISE_ON_EXCEPTION = False
    __DEFAULT_TIMESTAMP_FIELD_NAME = "timestamp"
    __DEFAULT_ISO_TIMESTAMP_FIELD_NAME = "iso_timestamp"

    __LOGGING_FILTER_FIELDS = ['msecs',
                               'relativeCreated',
                               'levelno',
                               'created']

    @staticmethod
    def _get_daily_index_name(es_index_name):
        """ Returns elasticearch index name :param: index_name the prefix to be used in the index :return: A srting containing the elasticsearch indexname used which should include the date. """
        # return "{0!s}-{1!s}".format(es_index_name, datetime.datetime.now().strftime('%Y.%m.%d'))
        return es_index_name

    @staticmethod
    def _get_weekly_index_name(es_index_name):
        """ Return elasticsearch index name :param: index_name the prefix to be used in the index :return: A srting containing the elasticsearch indexname used which should include the date and specific week """
        # current_date = datetime.datetime.now()
        # start_of_the_week = current_date - datetime.timedelta(days=current_date.weekday())
        # return "{0!s}-{1!s}".format(es_index_name, start_of_the_week.strftime('%Y.%m.%d'))
        return es_index_name

    @staticmethod
    def _get_monthly_index_name(es_index_name):
        """ Return elasticsearch index name :param: index_name the prefix to be used in the index :return: A srting containing the elasticsearch indexname used which should include the date and specific moth """
        # return "{0!s}-{1!s}".format(es_index_name, datetime.datetime.now().strftime('%Y.%m'))
        return es_index_name

    @staticmethod
    def _get_yearly_index_name(es_index_name):
        """ Return elasticsearch index name :param: index_name the prefix to be used in the index :return: A srting containing the elasticsearch indexname used which should include the date and specific year """
        # return "{0!s}-{1!s}".format(es_index_name, datetime.datetime.now().strftime('%Y'))
        return es_index_name

    _INDEX_FREQUENCY_FUNCION_DICT = {
    
        IndexNameFrequency.DAILY: _get_daily_index_name,
        IndexNameFrequency.WEEKLY: _get_weekly_index_name,
        IndexNameFrequency.MONTHLY: _get_monthly_index_name,
        IndexNameFrequency.YEARLY: _get_yearly_index_name
    }

    def __init__(self,
                 hosts=__DEFAULT_ELASTICSEARCH_HOST,
                 auth_details=(__DEFAULT_AUTH_USER, __DEFAULT_AUTH_PASSWD),
                 auth_type=__DEFAULT_AUTH_TYPE,
                 use_ssl=__DEFAULT_USE_SSL,
                 verify_ssl=__DEFAULT_VERIFY_SSL,
                 buffer_size=__DEFAULT_BUFFER_SIZE,
                 flush_frequency_in_sec=__DEFAULT_FLUSH_FREQ_INSEC,
                 es_index_name=__DEFAULT_ES_INDEX_NAME,
                 index_name_frequency=__DEFAULT_INDEX_FREQUENCY,
                 es_doc_type=__DEFAULT_ES_DOC_TYPE,
                 es_additional_fields=__DEFAULT_ADDITIONAL_FIELDS,
                 raise_on_indexing_exceptions=__DEFAULT_RAISE_ON_EXCEPTION,
                 default_iso_timestamp_field_name=__DEFAULT_ISO_TIMESTAMP_FIELD_NAME,
                 default_timestamp_field_name=__DEFAULT_TIMESTAMP_FIELD_NAME):
        """ Handler constructor :param hosts: The list of hosts that elasticsearch clients will connect. The list can be provided in the format ```[{'host':'host1','port':9200}, {'host':'host2','port':9200}]```to make sure the client supports failover of one of the instertion nodes :param auth_details: When ```CMRESHandler.AuthType.BASIC_AUTH```is used this argument must contain a tuple of string with the user and password that will be used to authenticate against the Elasticsearch servers, for example```('User','Password') :param auth_type: The authentication type to be used in the connection ```CMRESHandler.AuthType``` Currently, NO_AUTH, BASIC_AUTH, DEVOPS_AUTH are supported :param use_ssl: A boolean that defines if the communications should use SSL encrypted communication :param verify_ssl: A boolean that defines if the SSL certificates are validated or not :param buffer_size: An int, Once this size is reached on the internal buffer results are flushed into ES :param flush_frequency_in_sec: A float representing how often and when the buffer will be flushed, even if the buffer_size has not been reached yet :param es_index_name: A string with the prefix of the elasticsearch index that will be created. Note a date with YYYY.MM.dd, ```python_logger```used by default :param index_name_frequency: Defines what the date used in the postfix of the name would be. available values are selected from the IndexNameFrequency class (IndexNameFrequency.DAILY, IndexNameFrequency.WEEKLY, IndexNameFrequency.MONTHLY, IndexNameFrequency.YEARLY). By default it uses daily indices. :param es_doc_type: A string with the name of the document type that will be used ```python_log```used by default :param es_additional_fields: A dictionary with all the additional fields that you would like to add to the logs, such the application, environment, etc. :param raise_on_indexing_exceptions: A boolean, True only for debugging purposes to raise exceptions caused when :return: A ready to be used CMRESHandler. """
        logging.Handler.__init__(self)

        self.hosts = hosts
        self.auth_details = auth_details
        self.auth_type = auth_type
        self.use_ssl = use_ssl
        self.verify_certs = verify_ssl

        self.buffer_size = buffer_size
        self.flush_frequency_in_sec = flush_frequency_in_sec
        self.es_index_name = es_index_name
        self.index_name_frequency = index_name_frequency
        self.es_doc_type = es_doc_type
        self.es_additional_fields = es_additional_fields.copy()

        # 原始的报错：socket.gaierror: [Errno 8] nodename nor servname provided, or not known
        # self.es_additional_fields.update({'host': socket.gethostname(),
        # 'host_ip': socket.gethostbyname(socket.gethostname())})
        
        # 替换为下面的内容
        self.es_additional_fields.update({
    'host': socket.gethostname(),
                                          'host_ip': get_local_ip()})

        self.raise_on_indexing_exceptions = raise_on_indexing_exceptions
        self.default_iso_timestamp_field_name = default_iso_timestamp_field_name
        self.default_timestamp_field_name = default_timestamp_field_name

        self._client = None
        self._buffer = []
        self._buffer_lock = Lock()
        self._timer = None
        self._index_name_func = CMRESHandler._INDEX_FREQUENCY_FUNCION_DICT[self.index_name_frequency]
        self.serializer = CMRESSerializer()

    def __schedule_flush(self):
        if self._timer is None:
            self._timer = Timer(self.flush_frequency_in_sec, self.flush)
            self._timer.setDaemon(True)
            self._timer.start()

    def __get_es_client(self):
        if self.auth_type == CMRESHandler.AuthType.NO_AUTH:
            if self._client is None:
                self._client = Elasticsearch(hosts=self.hosts,
                                             use_ssl=self.use_ssl,
                                             verify_certs=self.verify_certs,
                                             connection_class=RequestsHttpConnection,
                                             serializer=self.serializer)
            return self._client

        if self.auth_type == CMRESHandler.AuthType.BASIC_AUTH:
            if self._client is None:
                return Elasticsearch(hosts=self.hosts,
                                     http_auth=self.auth_details,
                                     use_ssl=self.use_ssl,
                                     verify_certs=self.verify_certs,
                                     connection_class=RequestsHttpConnection,
                                     serializer=self.serializer)
            return self._client

        raise ValueError("Authentication method not supported")

    def test_es_source(self):
        """ Returns True if the handler can ping the Elasticsearch servers :return: A boolean, True if the connection against elasticserach host was successful """
        return self.__get_es_client().ping()

    @staticmethod
    def __get_es_datetime_str(timestamp):
        """ Returns elasticsearch utc formatted time for an epoch timestamp :param timestamp: epoch, including milliseconds :return: A string valid for elasticsearch time record """

        current_date = datetime.datetime.utcfromtimestamp(timestamp)
        return "{0!s}.{1}".format(
            datetime.datetime.strftime(current_date + datetime.timedelta(hours=8), '%Y-%m-%dT%H:%M:%S'),
            int(current_date.microsecond))

    def flush(self):
        """ Flushes the buffer into ES :return: None """
        if self._timer is not None and self._timer.is_alive():
            self._timer.cancel()
        self._timer = None

        if self._buffer:
            try:
                with self._buffer_lock:
                    logs_buffer = self._buffer
                    self._buffer = []
                actions = (
                    {
    
                        '_index': self._index_name_func.__func__(self.es_index_name),
                        '_type': self.es_doc_type,
                        '_source': log_record
                    }
                    for log_record in logs_buffer
                )
                eshelpers.bulk(
                    client=self.__get_es_client(),
                    actions=actions,
                    stats_only=True
                )
            except Exception as exception:
                if self.raise_on_indexing_exceptions:
                    raise exception

    def close(self):
        """ Flushes the buffer and release any outstanding resource :return: None """
        if self._timer is not None:
            self.flush()
        self._timer = None

    def emit(self, record):
        """ Emit overrides the abstract logging.Handler logRecord emit method Format and records the log :param record: A class of type ```logging.LogRecord``` :return: None """
        self.format(record)

        rec = self.es_additional_fields.copy()


        for key, value in record.__dict__.items():
            if key not in CMRESHandler.__LOGGING_FILTER_FIELDS:
                rec[key] = "" if value is None else value
        rec[self.default_timestamp_field_name] = self.__get_es_datetime_str(record.created)

        with self._buffer_lock:
            self._buffer.append(rec)

        if len(self._buffer) >= self.buffer_size:
            self.flush()
        else:
            self.__schedule_flush()

由于下面的库作用不大，就没有放在上面的文件中:

try:
    from requests_kerberos import HTTPKerberosAuth, DISABLED
    CMR_KERBEROS_SUPPORTED = True
except ImportError:
    CMR_KERBEROS_SUPPORTED = False

try:
    from requests_aws4auth import AWS4Auth
    AWS4AUTH_SUPPORTED = True
except ImportError:
    AWS4AUTH_SUPPORTED = False

3 调用方法写入es

调用的方法如下：

import logging
from handlers import CMRESHandler

LOG_LEVEL = 'DEBUG'  # 日志级别
LOG_FORMAT = '%(levelname)s - %(asctime)s - process: %(process)d - %(filename)s - %(name)s - %(lineno)d - %(module)s - %(message)s'  # 每条日志输出格式
ELASTIC_SEARCH_HOST = 'localhost'  # Elasticsearch Host
ELASTIC_SEARCH_PORT = 9200  # Elasticsearch Port
ELASTIC_SEARCH_INDEX = 'test_log3'  # Elasticsearch Index Name # system_log_24172335668239631
APP_ENVIRONMENT = 'dev'  # 运行环境，如测试环境还是生产环境

ELASTICSEARCH_USER = 'admin'
ELASTICSEARCH_PASSWORD = 'admin'

es_handler = CMRESHandler(hosts=[{
    'host': ELASTIC_SEARCH_HOST, 'port': ELASTIC_SEARCH_PORT}],
                                 # 用户名和密码
                                  auth_details=(ELASTICSEARCH_USER, ELASTICSEARCH_PASSWORD),
                                  # 可以配置对应的认证权限
                                  auth_type=CMRESHandler.AuthType.BASIC_AUTH,
                                  # 索引值
                                  es_index_name=ELASTIC_SEARCH_INDEX,
                                  # 额外增加环境标识
                                  es_additional_fields={
    'environment': APP_ENVIRONMENT}
                                  )

# 被注释的格式并未起任何作用
# es_handler.setLevel(level=LOG_LEVEL)
# formatter = logging.Formatter(LOG_FORMAT)
# es_handler.setFormatter(formatter)
logger = logging.getLogger('test')
logger.setLevel(LOG_LEVEL)
logger.addHandler(es_handler)
logger.debug('test write es2')

if __name__ == '__main__':
    pass

4 扩展

使用logging或loguru写入日志到es（三种方法）。