我使用Elasticsearch python API设计一个用户友好的应用程序，将解析后的结果放到elasticsearch服务器上。
我遇到的问题是，当我使用有效的url作为主机启动elasticsearch对象，而不是实际的elasticsearch主机地址时，我得到链式异常，如下所示：
Traceback (most recent call last):
File "/local/data/PYTHONLIB/lib/python3.5/site
packages/urllib3/connection.py", line 141, in _new_conn
(self.host, self.port), self.timeout, **extra_kw)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/util/connection.py", line 83, in create_connection
raise err
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/util/connection.py", line 73, in create_connection
sock.connect(sa)
OSError: [Errno 101] Network is unreachable
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/elasticsearch/connection/http_urllib3.py", line 166, in
perform_request
response = self.pool.urlopen(method, url, body, retries=False,
headers=request_headers, **kw)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connectionpool.py", line 639, in urlopen
_stacktrace=sys.exc_info()[2])
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/util/retry.py", line 333, in increment
raise six.reraise(type(error), error, _stacktrace)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/packages/six.py", line 686, in reraise
raise value
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connectionpool.py", line 601, in urlopen
chunked=chunked)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connectionpool.py", line 357, in _make_request
conn.request(method, url, **httplib_request_kw)
File "/usr/lib/python3.5/http/client.py", line 1106, in request
self._send_request(method, url, body, headers)
File "/usr/lib/python3.5/http/client.py", line 1151, in _send_request
self.endheaders(body)
File "/usr/lib/python3.5/http/client.py", line 1102, in endheaders
self._send_output(message_body)
File "/usr/lib/python3.5/http/client.py", line 934, in _send_output
self.send(msg)
File "/usr/lib/python3.5/http/client.py", line 877, in send
self.connect()
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connection.py", line 166, in connect
conn = self._new_conn()
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connection.py", line 150, in _new_conn
self, "Failed to establish a new connection: %s" % e)
urllib3.exceptions.NewConnectionError:
<urllib3.connection.HTTPConnection object at 0x7fc714997828>: Failed
to establish a new connection: [Errno 101] Network is unreachable
GET http://google.ca:9200/_nodes/_all/http [status:N/A
request:10.046s]
Traceback (most recent call last):
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connection.py", line 141, in _new_conn
(self.host, self.port), self.timeout, **extra_kw)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/util/connection.py", line 83, in
create_connection
raise err
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/util/connection.py", line 73, in create_connection
sock.connect(sa)
OSError: [Errno 101] Network is unreachable
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/elasticsearch/connection/http_urllib3.py", line 166, in
perform_request
response = self.pool.urlopen(method, url, body, retries=False,
headers=request_headers, **kw)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connectionpool.py", line 639, in urlopen
_stacktrace=sys.exc_info()[2])
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/util/retry.py", line 333, in increment
raise six.reraise(type(error), error, _stacktrace)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/packages/six.py", line 686, in reraise
raise value
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connectionpool.py", line 601, in urlopen
chunked=chunked)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connectionpool.py", line 357, in _make_request
conn.request(method, url, **httplib_request_kw)
File "/usr/lib/python3.5/http/client.py", line 1106, in request
self._send_request(method, url, body, headers)
File "/usr/lib/python3.5/http/client.py", line 1151, in
_send_request
self.endheaders(body)
File "/usr/lib/python3.5/http/client.py", line 1102, in endheaders
self._send_output(message_body)
File "/usr/lib/python3.5/http/client.py", line 934, in _send_output
self.send(msg)
File "/usr/lib/python3.5/http/client.py", line 877, in send
self.connect()
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connection.py", line 166, in connect
conn = self._new_conn()
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/urllib3/connection.py", line 150, in _new_conn
self, "Failed to establish a new connection: %s" % e)
urllib3.exceptions.NewConnectionError:
<urllib3.connection.HTTPConnection object at 0x7fc714997a20>: Failed
to establish a new connection: [Errno 101] Network is unreachable
Traceback (most recent call last):
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/elasticsearch/client/__init__.py", line 188, in __init__
self.transport = transport_class(_normalize_hosts(hosts), **kwargs)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/elasticsearch/transport.py", line 122, in __init__
self.sniff_hosts(True)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/elasticsearch/transport.py", line 235, in sniff_hosts
node_info = self._get_sniff_data(initial)
File "/local/data/PYTHONLIB/lib/python3.5/site-
packages/elasticsearch/transport.py", line 204, in _get_sniff_data
raise TransportError("N/A", "Unable to sniff hosts.")
elasticsearch.exceptions.TransportError: TransportError(N/A, 'Unable
to sniff hosts.')
我希望捕获所有异常并生成更加用户友好的错误消息，例如：＆＃34;主机无效，连接错误！＆＃34;
我试图在不泄露太多实施细节的情况下实现这一目标的是：
from urllib3.exceptions import NewConnectionError
from elasticsearch import TransportError
try:
Elasticsearch(http,
sniff_on_start=True,
sniff_on_connection_fail=True,
sniffer_timeout=60
)
except (OSError, NewConnectionError, TransportError) as e:
print("Invalid host, connection error!")
raise SystemExit(1)
或：
from urllib3.exceptions import NewConnectionError
from elasticsearch import TransportError
try:
Elasticsearch(http,
sniff_on_start=True,
sniff_on_connection_fail=True,
sniffer_timeout=60
)
except Exception as e:
print("Invalid host, connection error!")
raise SystemExit(1)
或：
from urllib3.exceptions import NewConnectionError
from elasticsearch import TransportError
try:
try:
try:
Elasticsearch(http,
sniff_on_start=True,
sniff_on_connection_fail=True,
sniffer_timeout=60
)
except NewConnectionError as e:
print("Caught NewConnectionError")
except OSError as e:
print("Caught OSError")
except TransportError as e:
print("Invalid host, connection error!")
raise SystemExit(1)
但是每次试验，我只能捕获TransportError，它是elasticsearch API抛出的最后一个异常。 有没有办法让我在不改变源代码中抛出异常的方式之前实际捕获所有异常？