Adding more descriptive exception messages to client

Errors occuring during login were not very descriptive. This
patch adds more details about why a login to a LH backend failed.

Also, added the ability to toggle debug on before the client has
been initialized.

bug reference:
https://github.com/hp-storage/python-3parclient/issues/9

Change-Id: I7fe700ae11703dabd82436a105f634ddd5e8b8b1

docs/changelog.rst

@@ -51,3 +51,9 @@ Changes in Version 1.0.4
 * Added tox environments to run tests with code coverage and to generate the documentation
 * Consolidated the test/README.rst into the top level README.rst and added clarifications
 * Added the ability for getVolumes to filter based on cluster and fields.
+
+Changes in Version 1.0.5
+------------------------
+
+* Added improved error handling during login attempts.  Errors will now be
+  more descriptive in why a login failed.

hplefthandclient/__init__.py

@@ -24,7 +24,7 @@ HP LeftHand REST Client
 
 """
 
-version_tuple = (1, 0, 4)
+version_tuple = (1, 0, 5)
 
 
 def get_version_string():

hplefthandclient/client.py

@@ -35,16 +35,18 @@ except ImportError:
     # Fall back to Python 2's urllib2
     from urllib2 import quote
 
-from hplefthandclient import http
+from hplefthandclient import exceptions, http
 
 
 class HPLeftHandClient:
 
-    def __init__(self, api_url):
+    def __init__(self, api_url, debug=False):
         self.api_url = api_url
         self.http = http.HTTPJSONRESTClient(self.api_url)
         self.api_version = None
 
+        self.debug_rest(debug)
+
     def debug_rest(self, flag):
         """
         This is useful for debugging requests to LeftHand
@@ -67,8 +69,21 @@ class HPLeftHandClient:
         :returns: None
 
         """
-        resp = self.http.authenticate(username, password)
-        self.api_version = resp['x-api-version']
+        try:
+            resp = self.http.authenticate(username, password)
+            self.api_version = resp['x-api-version']
+        except Exception as ex:
+            ex_desc = ex.get_description()
+
+            if (ex_desc and "Unable to find the server at" in ex_desc or
+                    "Only absolute URIs are allowed" in ex_desc):
+                raise exceptions.HTTPBadRequest(ex_desc)
+            else:
+                msg = ('Error: \'%s\' - Error communicating with the LeftHand '
+                       'API. Check proxy settings. If error persists, either '
+                       'the LeftHand API is not running or the version of the '
+                       'API is not supported.') % ex_desc
+                raise exceptions.UnsupportedVersion(msg)
 
     def logout(self):
         """

hplefthandclient/exceptions.py

@@ -54,16 +54,27 @@ class ClientException(Exception):
     """
     _error_code = None
     _error_desc = None
+    _error_ref = None
 
     _debug1 = None
     _debug2 = None
 
     def __init__(self, error=None):
-        if error:
-            if 'messageID' in error:
-                self._error_code = error['messageID']
-            if 'message' in error:
-                self._error_desc = error['message']
+        super(ClientException, self).__init__()
+
+        if not error:
+            return
+
+        if isinstance(error, str):
+            # instead of KeyError below, take it and make it the _error_desc.
+            self._error_desc = error
+        else:
+            if 'code' in error:
+                self._error_code = error['code']
+            if 'desc' in error:
+                self._error_desc = error['desc']
+            if 'ref' in error:
+                self._error_ref = error['ref']
 
             if 'debug1' in error:
                 self._debug1 = error['debug1']
@@ -76,6 +87,9 @@ class ClientException(Exception):
     def get_description(self):
         return self._error_desc
 
+    def get_ref(self):
+        return self._error_ref
+
     def __str__(self):
         formatted_string = "%s (HTTP %s)" % (self.message, self.http_status)
         if self._error_code: