Plumb python support

extensions/s3/src/main/java/io/deephaven/extensions/s3/S3Instructions.java

@@ -142,6 +142,10 @@ public interface Builder {
 
         Builder endpointOverride(URI endpointOverride);
 
+        default Builder endpointOverride(String endpointOverride) {
+            return endpointOverride(URI.create(endpointOverride));
+        }
+
         S3Instructions build();
     }
 

py/server/deephaven/experimental/s3.py

@@ -39,7 +39,8 @@ def __init__(self,
                  read_timeout: Union[
                      Duration, int, str, datetime.timedelta, np.timedelta64, pd.Timedelta, None] = None,
                  aws_access_key_id: Optional[str] = None,
-                 aws_secret_access_key: Optional[str] = None):
+                 aws_secret_access_key: Optional[str] = None,
+                 endpoint_override: Optional[str] = None):
 
         """
         Initializes the instructions.
@@ -68,6 +69,7 @@ def __init__(self,
             aws_secret_access_key (str): the AWS secret access key for reading parquet files stored in AWS S3. Both
                 access key and secret key must be provided to use static credentials, else default credentials will be
                 used from software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider.
+            endpoint_override (str): the endpoint with which the SDK should communicate.
 
         Raises:
             DHError: If unable to build the instructions object.
@@ -102,6 +104,9 @@ def __init__(self,
             if aws_access_key_id is not None:
                 builder.credentials(_JAwsCredentials.basicCredentials(aws_access_key_id, aws_secret_access_key))
 
+            if endpoint_override is not None:
+                builder.endpointOverride(endpoint_override)
+
             self._j_object = builder.build()
         except Exception as e:
             raise DHError(e, "Failed to build S3 instructions") from e