xenapi: support the session when xenserver is slave

current xenapi inspector is only support the session to master
xenserver, and when xenserver is slave mode the session could
not be created successfully.

Change-Id: Icbcd497f0c5e50984d24f46f8db519f1eb2e0296
Closes-Bug: 1484768

ceilometer/compute/virt/xenapi/inspector.py

@@ -15,6 +15,7 @@
 
 from oslo_config import cfg
 from oslo_utils import units
+import six.moves.urllib.parse as urlparse
 try:
     import XenAPI as api
 except ImportError:
@@ -48,6 +49,18 @@ class XenapiException(virt_inspector.InspectorException):
     pass
 
 
+def swap_xapi_host(url, host_addr):
+    """Replace the XenServer address present in 'url' with 'host_addr'."""
+    temp_url = urlparse.urlparse(url)
+    # The connection URL is served by XAPI and doesn't support having a
+    # path for the connection url after the port. And username/password
+    # will be pass separately. So the URL like "http://abc:abc@abc:433/abc"
+    # should not appear for XAPI case.
+    temp_netloc = temp_url.netloc.replace(temp_url.hostname, '%s' % host_addr)
+    replaced = temp_url._replace(netloc=temp_netloc)
+    return urlparse.urlunparse(replaced)
+
+
 def get_api_session():
     if not api:
         raise ImportError(_('XenAPI not installed'))
@@ -64,8 +77,18 @@ def get_api_session():
                    else api.Session(url))
         session.login_with_password(username, password)
     except api.Failure as e:
-        msg = _("Could not connect to XenAPI: %s") % e.details[0]
-        raise XenapiException(msg)
+        if e.details[0] == 'HOST_IS_SLAVE':
+            master = e.details[1]
+            url = swap_xapi_host(url, master)
+            try:
+                session = api.Session(url)
+                session.login_with_password(username, password)
+            except api.Failure as es:
+                raise XenapiException(_('Could not connect slave host: %s ') %
+                                      es.details[0])
+        else:
+            msg = _("Could not connect to XenAPI: %s") % e.details[0]
+            raise XenapiException(msg)
     return session
 
 

ceilometer/tests/unit/compute/virt/xenapi/test_inspector.py

@@ -21,6 +21,33 @@ from ceilometer.compute.virt import inspector as virt_inspector
 from ceilometer.compute.virt.xenapi import inspector as xenapi_inspector
 
 
+class TestSwapXapiHost(base.BaseTestCase):
+
+    def test_swapping(self):
+        self.assertEqual(
+            "http://otherserver:8765/somepath",
+            xenapi_inspector.swap_xapi_host(
+                "http://someserver:8765/somepath", 'otherserver'))
+
+    def test_no_port(self):
+        self.assertEqual(
+            "http://otherserver/somepath",
+            xenapi_inspector.swap_xapi_host(
+                "http://someserver/somepath", 'otherserver'))
+
+    def test_no_path(self):
+        self.assertEqual(
+            "http://otherserver",
+            xenapi_inspector.swap_xapi_host(
+                "http://someserver", 'otherserver'))
+
+    def test_same_hostname_path(self):
+        self.assertEqual(
+            "http://other:80/some",
+            xenapi_inspector.swap_xapi_host(
+                "http://some:80/some", 'other'))
+
+
 class TestXenapiInspection(base.BaseTestCase):
 
     def setUp(self):