[Fix] Bedrock Embeddings - Ensure correct aws_region is used when provided dynamically (#16547)

* test_bedrock_embedding_uses_correct_region_when_specified

* fix aws_region_name in bedrock embeddings

litellm/llms/bedrock/embed/embedding.py

@@ -391,7 +391,7 @@ class BedrockEmbedding(BaseAWSLLM):
         )  # default to model if not passed
         modelId = urllib.parse.quote(unencoded_model_id, safe="")
         aws_region_name = self._get_aws_region_name(
-            optional_params=optional_params,
+            optional_params={"aws_region_name": aws_region_name},
             model=model,
             model_id=unencoded_model_id,
         )

tests/llm_translation/test_bedrock_embedding.py

@@ -336,3 +336,116 @@ async def test_e2e_bedrock_async_invoke_embedding_async_twelvelabs_marengo():
     # Restore original region name
     if original_region_name:
         os.environ["AWS_REGION_NAME"] = original_region_name
+
+
+titan_embedding_response = {"embedding": [0.1, 0.2, 0.3], "inputTextTokenCount": 10}
+
+
+def test_bedrock_embedding_uses_correct_region_when_specified():
+    """
+    Test that when aws_region_name is explicitly passed, it's used correctly
+    even if AWS_REGION_NAME env var is set to a different region.
+
+    relevant issue: https://github.com/BerriAI/litellm/issues/16517
+    """
+    # Save original env var
+    original_region_name = os.environ.get("AWS_REGION_NAME")
+    
+    # Set env var to a different region (this should NOT be used)
+    os.environ["AWS_REGION_NAME"] = "ap-northeast-1"
+    
+    try:
+        client = HTTPHandler()
+        
+        with patch.object(client, "post") as mock_post:
+            mock_response = Mock()
+            mock_response.status_code = 200
+            mock_response.text = json.dumps(titan_embedding_response)
+            mock_response.json = lambda: json.loads(mock_response.text)
+            mock_post.return_value = mock_response
+            
+            # Call with explicit region
+            response = litellm.embedding(
+                model="bedrock/amazon.titan-embed-image-v1",
+                input=["test input"],
+                client=client,
+                aws_region_name="us-east-1",  # Explicitly set to us-east-1
+            )
+            
+            # Verify the request was made to the correct region
+            assert mock_post.called, "HTTP post should have been called"
+            
+            # Get the URL from the call
+            call_args = mock_post.call_args
+            url = call_args.kwargs.get("url", "")
+            
+            # The URL should contain us-east-1, NOT ap-northeast-1
+            assert "us-east-1" in url, f"URL should contain us-east-1, but got: {url}"
+            assert "ap-northeast-1" not in url, f"URL should NOT contain ap-northeast-1, but got: {url}"
+            
+            print(f"✓ Test passed: URL contains correct region: {url}")
+            
+    finally:
+        # Restore original env var
+        if original_region_name:
+            os.environ["AWS_REGION_NAME"] = original_region_name
+        else:
+            os.environ.pop("AWS_REGION_NAME", None)
+
+
+def test_bedrock_embedding_region_bug_reproduction():
+    """
+    Reproduces the bug where aws_region_name is ignored when passed explicitly.
+    
+    relevant issue: https://github.com/BerriAI/litellm/issues/16517
+    """
+    # Save original env var
+    original_region_name = os.environ.get("AWS_REGION_NAME")
+    
+    # Set env var to ap-northeast-1 (this is what the bug report shows)
+    os.environ["AWS_REGION_NAME"] = "ap-northeast-1"
+    
+    try:
+        client = HTTPHandler()
+        
+        with patch.object(client, "post") as mock_post:
+            mock_response = Mock()
+            mock_response.status_code = 200
+            mock_response.text = json.dumps(titan_embedding_response)
+            mock_response.json = lambda: json.loads(mock_response.text)
+            mock_post.return_value = mock_response
+            
+            # Call with explicit region (as in the bug report)
+            response = litellm.embedding(
+                model="bedrock/amazon.titan-embed-image-v1",
+                input=["test input"],
+                client=client,
+                aws_region_name="us-east-1",  # Explicitly set to us-east-1
+            )
+            
+            # Verify the request was made
+            assert mock_post.called, "HTTP post should have been called"
+            
+            # Get the URL from the call
+            call_args = mock_post.call_args
+            url = call_args.kwargs.get("url", "")
+            
+            print(f"Request URL: {url}")
+            print(f"Expected region in URL: us-east-1")
+            print(f"Environment AWS_REGION_NAME: {os.environ.get('AWS_REGION_NAME')}")
+            
+            # This assertion will FAIL if the bug exists (it will use ap-northeast-1)
+            # This assertion will PASS if the bug is fixed (it will use us-east-1)
+            if "ap-northeast-1" in url:
+                print("❌ BUG REPRODUCED: Using wrong region from env var instead of explicit parameter")
+                assert False, f"Bug reproduced: URL contains ap-northeast-1 instead of us-east-1. URL: {url}"
+            else:
+                print("✓ Bug NOT reproduced: Using correct region from explicit parameter")
+                assert "us-east-1" in url, f"URL should contain us-east-1, but got: {url}"
+            
+    finally:
+        # Restore original env var
+        if original_region_name:
+            os.environ["AWS_REGION_NAME"] = original_region_name
+        else:
+            os.environ.pop("AWS_REGION_NAME", None)