Fix server exception classes (#1683)

str(e) and e.message will both show the error message.
refactored the error.py file to simplify our exception class definitions

server/common/errors.py

@@ -1,85 +1,47 @@
 from http import HTTPStatus
 
 
-class RequestException(Exception):
+class CellxgeneException(Exception):
+    """Base class for cellxgene exceptions"""
+
+    def __init__(self, message):
+        self.message = message
+        super().__init__(message)
+
+
+class RequestException(CellxgeneException):
     """Baseclass for exceptions that can be raised from a request."""
 
     # The default status code is 400 (Bad Request)
     default_status_code = HTTPStatus.BAD_REQUEST
 
     def __init__(self, message, status_code=None):
-        Exception.__init__(self)
-        self.message = message
+        super().__init__(message)
         self.status_code = status_code or self.default_status_code
 
 
-class FilterError(RequestException):
-    """Raised when filter is malformed"""
-
-    pass
+def define_exception(name, doc):
+    globals()[name] = type(name, (CellxgeneException,), dict(__doc__=doc))
 
 
-class JSONEncodingValueError(RequestException):
-    """Raised when data cannot be encoded into json"""
-
-    pass
+def define_request_exception(name, doc, default_status_code=HTTPStatus.BAD_REQUEST):
+    globals()[name] = type(name, (RequestException,), dict(__doc__=doc, default_status_code=default_status_code))
 
 
-class MimeTypeError(RequestException):
-    """Raised when incompatible MIME type selected"""
+define_request_exception("FilterError", "Raised when filter is malformed")
+define_request_exception("JSONEncodingValueError", "Raised when data cannot be encoded into json")
+define_request_exception("MimeTypeError", "Raised when incompatible MIME type selected")
+define_request_exception("DatasetAccessError", "Raised when file loaded into a DataAdaptor is misformatted")
+define_request_exception("DisabledFeatureError", "Raised when an attempt to use a disabled feature occurs")
+define_request_exception("AnnotationsError", "Raised when an attempt to use the annotations feature fails")
+define_request_exception(
+    "ComputeError",
+    "Raised when an error occurs during a compute algorithm (such as diffexp)",
+    HTTPStatus.INTERNAL_SERVER_ERROR,
+)
+define_request_exception("ExceedsLimitError", "Raised when an HTTP request exceeds a limit/quota")
+define_request_exception("ColorFormatException", "Raised when color helper functions encounter an unknown color format")
 
-    pass
-
-
-class DatasetAccessError(RequestException):
-    """Raised when file loaded into a DataAdaptor is misformatted"""
-
-    pass
-
-
-class DisabledFeatureError(RequestException):
-    """Raised when an attempt to use a disabled feature occurs"""
-
-    pass
-
-
-class AnnotationsError(RequestException):
-    """Raised when an attempt to use the annotations feature fails"""
-
-    pass
-
-
-class ComputeError(RequestException):
-    """Raised when an error occurs during a compute algorithm (such as diffexp)"""
-
-    default_status_code = HTTPStatus.INTERNAL_SERVER_ERROR
-
-
-class ExceedsLimitError(RequestException):
-    """Raised when an HTTP request exceeds a limit/quota"""
-
-    pass
-
-
-class ColorFormatException(RequestException):
-    """Raised when color helper functions encounter an unknown color format"""
-
-    pass
-
-
-class OntologyLoadFailure(Exception):
-    """Raised when reading the ontology file fails"""
-
-    pass
-
-
-class ConfigurationError(Exception):
-    """Raised when checking configuration errors"""
-
-    pass
-
-
-class PrepareError(Exception):
-    """Raised when data is misprepared"""
-
-    pass
+define_exception("OntologyLoadFailure", "Raised when reading the ontology file fails")
+define_exception("ConfigurationError", "Raised when checking configuration errors")
+define_exception("PrepareError", "Raised when data is misprepared")