Fix Amazon OpenSearch Serverless integration with LangChain. (opensearch-project#603)

Signed-off-by: dblock <dblock@amazon.com>

Author: dblock

CHANGELOG.md

@@ -8,6 +8,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Removed
 ### Fixed
 - Fix `TypeError` on `parallel_bulk` ([#601](https://github.com/opensearch-project/opensearch-py/pull/601))
+- Fix Amazon OpenSearch Serverless integration with LangChain ([#603](https://github.com/opensearch-project/opensearch-py/pull/603))
 ### Security
 
 ## [2.4.1]

opensearchpy/helpers/signer.py

@@ -78,6 +78,7 @@ class RequestsAWSV4SignerAuth(requests.auth.AuthBase):
 
     def __init__(self, credentials, region, service: str = "es") -> None:  # type: ignore
         self.signer = AWSV4Signer(credentials, region, service)
+        self.service = service  # tools like LangChain rely on this, see https://github.com/opensearch-project/opensearch-py/issues/600
 
     def __call__(self, request):  # type: ignore
         return self._sign_request(request)  # type: ignore
@@ -133,6 +134,7 @@ class AWSV4SignerAuth(RequestsAWSV4SignerAuth):
 class Urllib3AWSV4SignerAuth(Callable):  # type: ignore
     def __init__(self, credentials, region, service: str = "es") -> None:  # type: ignore
         self.signer = AWSV4Signer(credentials, region, service)
+        self.service = service  # tools like LangChain rely on this, see https://github.com/opensearch-project/opensearch-py/issues/600
 
     def __call__(self, method: str, url: str, body: Any) -> Dict[str, str]:
         return self.signer.sign(method, url, body)

test_opensearchpy/test_connection/test_requests_http_connection.py

@@ -460,6 +460,7 @@ def test_aws_signer_as_http_auth(self) -> None:
         from opensearchpy.helpers.signer import RequestsAWSV4SignerAuth
 
         auth = RequestsAWSV4SignerAuth(self.mock_session(), region)
+        self.assertEqual(auth.service, "es")
         con = RequestsHttpConnection(http_auth=auth)
         prepared_request = requests.Request("GET", "http://localhost").prepare()
         auth(prepared_request)
@@ -478,6 +479,7 @@ def test_aws_signer_when_service_is_specified(self) -> None:
         from opensearchpy.helpers.signer import RequestsAWSV4SignerAuth
 
         auth = RequestsAWSV4SignerAuth(self.mock_session(), region, service)
+        self.assertEqual(auth.service, service)
         con = RequestsHttpConnection(http_auth=auth)
         prepared_request = requests.Request("GET", "http://localhost").prepare()
         auth(prepared_request)

test_opensearchpy/test_connection/test_urllib3_http_connection.py

@@ -192,6 +192,7 @@ def test_aws_signer_as_http_auth_adds_headers(self, mock_open: Any) -> None:
         from opensearchpy.helpers.signer import Urllib3AWSV4SignerAuth
 
         auth = Urllib3AWSV4SignerAuth(self.mock_session(), "us-west-2")
+        self.assertEqual(auth.service, "es")
         con = Urllib3HttpConnection(http_auth=auth, headers={"x": "y"})
         con.perform_request("GET", "/")
         self.assertEqual(mock_open.call_count, 1)
@@ -249,6 +250,7 @@ def test_aws_signer_when_service_is_specified(self) -> None:
         from opensearchpy.helpers.signer import Urllib3AWSV4SignerAuth
 
         auth = Urllib3AWSV4SignerAuth(self.mock_session(), region, service)
+        self.assertEqual(auth.service, service)
         headers = auth("GET", "http://localhost", None)
         self.assertIn("Authorization", headers)
         self.assertIn("X-Amz-Date", headers)