Elasticsearch Ping报错：NodeConfig缺少必填参数scheme

我尝试运行以下代码连接Elasticsearch：

def connect ():
        es = None
        es = Elasticsearch([{'host': 'localhost', 'port': 9200}])
        print(es.ping())

但出现如下错误：

/Users/USER/PycharmProjects/practical_week4_ex_1/venv/bin/python /Users/USER/PycharmProjects/practical_week4_ex_1/scratch.py 
Traceback (most recent call last):
  File "/Users/USER/PycharmProjects/practical_week4_ex_1/scratch.py", line 7, in <module>
    es = Elasticsearch([{'host': 'localhost', 'port': 9200}])
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/USER/PycharmProjects/practical_week4_ex_1/venv/lib/python3.11/site-packages/elasticsearch/_sync/client/__init__.py", line 333, in __init__
    node_configs = client_node_configs(
                   ^^^^^^^^^^^^^^^^^^^^
  File "/Users/USER/PycharmProjects/practical_week4_ex_1/venv/lib/python3.11/site-packages/elasticsearch/_sync/client/utils.py", line 105, in client_node_configs
    node_configs = hosts_to_node_configs(hosts)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/USER/PycharmProjects/practical_week4_ex_1/venv/lib/python3.11/site-packages/elasticsearch/_sync/client/utils.py", line 154, in hosts_to_node_configs
    node_configs.append(host_mapping_to_node_config(host))
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/USER/PycharmProjects/practical_week4_ex_1/venv/lib/python3.11/site-packages/elasticsearch/_sync/client/utils.py", line 221, in host_mapping_to_node_config
    return NodeConfig(**options)  # type: ignore
           ^^^^^^^^^^^^^^^^^^^^^
TypeError: NodeConfig.__init__() missing 1 required positional argument: 'scheme'

Process finished with exit code 1

问题原因 #

你使用的是Elasticsearch Python客户端8.x版本，该版本API做了兼容性变更，不再支持仅传入host和port的旧格式，必须明确指定通信协议的scheme（http或https）。

修复方案 #

有两种简洁的修复方式：

方式1：在host配置字典中添加scheme参数 #

from elasticsearch import Elasticsearch

def connect():
    es = None
    # 新增scheme字段，本地Elasticsearch默认使用http协议
    es = Elasticsearch([{'host': 'localhost', 'port': 9200, 'scheme': 'http'}])
    print(es.ping())

connect()

方式2：直接传入完整URL字符串（推荐） #

这种写法更简洁直观，直接包含协议、主机和端口：

from elasticsearch import Elasticsearch

def connect():
    es = None
    es = Elasticsearch("http://localhost:9200")
    print(es.ping())

connect()

验证结果 #

如果本地Elasticsearch服务正常运行，修复后的代码会输出True，表示连接成功。

内容的提问来源于stack exchange，提问作者YousefMenesy