Add optional error_message to adapter.request

When we make REST cals, sometimes we want to provide a more helpful
error string. Add an optional argument to the calls to allow this.

Change-Id: I797e34cda9f27c18d66a42fd5860fe572fa55ada

shade/_adapter.py

@@ -111,8 +111,8 @@ class ShadeAdapter(adapter.Adapter):
         self.request_log.debug(tmpl.format(**kwargs))
         return response
 
-    def _munch_response(self, response, result_key=None):
-        exc.raise_from_response(response)
+    def _munch_response(self, response, result_key=None, error_message=None):
+        exc.raise_from_response(response, error_message=error_message)
 
         if not response.content:
             # This doens't have any content
@@ -154,7 +154,9 @@ class ShadeAdapter(adapter.Adapter):
             return meta.obj_to_dict(result)
         return result
 
-    def request(self, url, method, run_async=False, *args, **kwargs):
+    def request(
+            self, url, method, run_async=False, error_message=None,
+            *args, **kwargs):
         name_parts = extract_name(url)
         name = '.'.join([self.service_type, method] + name_parts)
         class_name = "".join([
@@ -179,4 +181,4 @@ class ShadeAdapter(adapter.Adapter):
         if run_async:
             return response
         else:
-            return self._munch_response(response)
+            return self._munch_response(response, error_message=error_message)

shade/exc.py

@@ -89,18 +89,36 @@ OpenStackCloudResourceNotFound = OpenStackCloudURINotFound
 
 
 # Logic shamelessly stolen from requests
-def raise_from_response(response):
+def raise_from_response(response, error_message=None):
     msg = ''
+    if error_message:
+        msg = _
     if 400 <= response.status_code < 500:
-        msg = '({code}) Client Error: {reason} for url: {url}'.format(
-            code=response.status_code,
-            reason=response.reason,
-            url=response.url)
+        source = "Client"
     elif 500 <= response.status_code < 600:
-        msg = '({code}) Server Error: {reason} for url: {url}'.format(
-            code=response.status_code,
+        source = "Server"
+    else:
+        source = None
+
+    if response.reason:
+        remote_error = "Error: {reason} for {url}".format(
             reason=response.reason,
             url=response.url)
+    else:
+        remote_error = "Error for url: {url}".format(url=response.url)
+
+    if source:
+        if error_message:
+            msg = '{error_message}. ({code}) {source} {remote_error}'.format(
+                error_message=error_message,
+                source=source,
+                code=response.status_code,
+                remote_error=remote_error)
+        else:
+            msg = '({code}) {source} {remote_error}'.format(
+                code=response.status_code,
+                source=source,
+                remote_error=remote_error)
 
     # Special case 404 since we raised a specific one for neutron exceptions
     # before