fix urllib3.exceptions.ClosedPoolError breaking synchronous client …

…after `close`

Signed-off-by: odlmarce <[email protected]>

opensearchpy/connection/http_urllib3.py

@@ -214,9 +214,14 @@ def __init__(
         if pool_maxsize and isinstance(pool_maxsize, int):
             kw["maxsize"] = pool_maxsize
 
-        self.pool = pool_class(
-            self.hostname, port=self.port, timeout=self.timeout, **kw
-        )
+        def urllib3_pool_factory() -> Any:
+            return pool_class(self.hostname, port=self.port, timeout=self.timeout, **kw)
+
+        self._urllib3_pool_factory = urllib3_pool_factory
+        self._create_urllib3_pool()
+
+    def _create_urllib3_pool(self) -> None:
+        self.pool = self._urllib3_pool_factory()
 
     def perform_request(
         self,
@@ -228,6 +233,10 @@ def perform_request(
         ignore: Collection[int] = (),
         headers: Optional[Mapping[str, str]] = None,
     ) -> Any:
+        if self.pool is None:
+            self._create_urllib3_pool()
+        assert self.pool is not None
+
         url = self.url_prefix + url
         if params:
             url = "%s?%s" % (url, urlencode(params))
@@ -305,4 +314,6 @@ def close(self) -> None:
         """
         Explicitly closes connection
         """
-        self.pool.close()
+        if self.pool:
+            self.pool.close()
+            self.pool = None