Create error code lookup function

Reduce file name from error_code_registry to errors. Use lookup function to access the error codes and throw a ValueError in case the error could not be found. Add all error hexa codes to the registry. The additional data is not replacing the error description, so remove test covering that incorrect case.

Author: jdecuyper

hyper/http20/connection.py

@@ -19,8 +19,8 @@
 from .response import HTTP20Response, HTTP20Push
 from .window import FlowControlManager
 from .exceptions import ConnectionError
-from .error_code_registry import H2_ERROR_CODE_REGISTRY
 
+import hyper.http20.errors as errors
 import errno
 import logging
 import socket
@@ -379,21 +379,17 @@ def receive_frame(self, frame):
             # If an error occured, try to read the error description from
             # code registry otherwise use the frame's additional data.
             if frame.error_code != 0:
-                err_no = hex(frame.error_code)
-
-                if frame.error_code > 0 and \
-                   frame.error_code < len(H2_ERROR_CODE_REGISTRY):
-                    err_name = H2_ERROR_CODE_REGISTRY[frame.error_code]['Name']
-                    err_description = frame.additional_data or \
-                       H2_ERROR_CODE_REGISTRY[frame.error_code]['Description']
+                try:
+                    name, number, description = errors.get_data(frame.error_code)
+                except ValueError:
+                    error_string = ("Encountered error code %d, extra data %s" %
+                                   (frame.error_code, frame.additional_data))
                 else:
-                    err_name = frame.error_code;
-                    err_description = frame.additional_data
+                    error_string = ("Encountered error %s %s: %s" %
+                                   (name, number, description))
+
+                raise ConnectionError(error_string)
 
-                raise ConnectionError(
-                    "Encountered error %s %s: %s." % (err_name, err_no,
-                     err_description)
-                )
         elif frame.type == BlockedFrame.type:
             increment = self.window_manager._blocked()
             if increment:

hyper/http20/error_code_registry.py renamed to hyper/http20/errors.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 """
-hyper/http20/error_code_registry
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+hyper/http20/errorserrors
+~~~~~~~~~~~~~~~~~~~
 
 Global error code registry containing the established HTTP/2 error codes.
 The registry is based on a 32-bit space so we use the error code to index into
@@ -12,38 +12,64 @@
 """
 
 NO_ERROR =            {'Name': 'NO_ERROR',
+                       'Code': '0x0',
                        'Description': 'Graceful shutdown'}
 PROTOCOL_ERROR =      {'Name': 'PROTOCOL_ERROR',
+                       'Code': '0x1',
                        'Description': 'Protocol error detected'}
 INTERNAL_ERROR =      {'Name': 'INTERNAL_ERROR',
+                       'Code': '0x2',
                        'Description': 'Implementation fault'}
 FLOW_CONTROL_ERROR =  {'Name': 'FLOW_CONTROL_ERROR',
+                       'Code': '0x3',
                        'Description': 'Flow control limits exceeded'}
 SETTINGS_TIMEOUT =    {'Name': 'SETTINGS_TIMEOUT',
+                       'Code': '0x4',
                        'Description': 'Settings not acknowledged'}
 STREAM_CLOSED =       {'Name': 'STREAM_CLOSED',
+                       'Code': '0x5',
                        'Description': 'Frame received for closed stream'}
 FRAME_SIZE_ERROR =    {'Name': 'FRAME_SIZE_ERROR',
+                       'Code': '0x6',
                        'Description': 'Frame size incorrect'}
 REFUSED_STREAM =      {'Name': 'REFUSED_STREAM ',
+                       'Code': '0x7',
                        'Description': 'Stream not processed'}
 CANCEL =              {'Name': 'CANCEL',
+                       'Code': '0x8',
                        'Description': 'Stream cancelled'}
 COMPRESSION_ERROR =   {'Name': 'COMPRESSION_ERROR',
+                       'Code': '0x9',
                        'Description': 'Compression state not updated'}
 CONNECT_ERROR =       {'Name': 'CONNECT_ERROR',
+                       'Code': '0xa',
                        'Description': 
                        'TCP connection error for CONNECT method'}
 ENHANCE_YOUR_CALM =   {'Name': 'ENHANCE_YOUR_CALM',
+                       'Code': '0xb',
                        'Description': 'Processing capacity exceeded'}
 INADEQUATE_SECURITY = {'Name': 'INADEQUATE_SECURITY',
+                       'Code': '0xc',
                        'Description': 
                        'Negotiated TLS parameters not acceptable'}
 HTTP_1_1_REQUIRED =   {'Name': 'HTTP_1_1_REQUIRED', 
+                       'Code': '0xd',
                        'Description': 'Use HTTP/1.1 for the request'}
 
-H2_ERROR_CODE_REGISTRY = [NO_ERROR, PROTOCOL_ERROR, INTERNAL_ERROR,
-                          FLOW_CONTROL_ERROR, SETTINGS_TIMEOUT, STREAM_CLOSED,
-                          FRAME_SIZE_ERROR, REFUSED_STREAM, CANCEL,
-                          COMPRESSION_ERROR, CONNECT_ERROR, ENHANCE_YOUR_CALM,
-                          INADEQUATE_SECURITY, HTTP_1_1_REQUIRED]
+H2_ERRORS = [NO_ERROR, PROTOCOL_ERROR, INTERNAL_ERROR, FLOW_CONTROL_ERROR,
+             SETTINGS_TIMEOUT, STREAM_CLOSED, FRAME_SIZE_ERROR, REFUSED_STREAM,
+             CANCEL, COMPRESSION_ERROR, CONNECT_ERROR, ENHANCE_YOUR_CALM,
+             INADEQUATE_SECURITY, HTTP_1_1_REQUIRED]
+
+def get_data(error_code):
+    """
+    Lookup the error code description, if not available throw a value error
+    """
+    if error_code < 0 or error_code >= len(H2_ERRORS):
+        raise ValueError("Error code is invalid")
+
+    name = H2_ERRORS[error_code]['Name']
+    number = H2_ERRORS[error_code]['Code']
+    description = H2_ERRORS[error_code]['Description']
+
+    return name, number, description