[Kimchi-devel] [PATCH] Avoid useless libvirt error log produced by featuretests

[Aline Manera]

From: apporc <appleorchard2000 at gmail.com>

When running feature tests, we get bunch of error messages as below:

*** Running feature tests ***
libvirt: Domain Config error : internal error unknown protocol type 'http'
libvirt: Domain Config error : internal error unknown protocol type 'https'
libvirt: Domain Config error : internal error unknown protocol type 'ftp'
libvirt: Domain Config error : internal error unknown protocol type 'ftps'
libvirt: Domain Config error : internal error unknown protocol type 'tftp'
Cannot find '' in path: No such file or directory
*** Feature tests completed ***

By replacing default error handler of libvirt, this patch succeeded to
avoid the errors. After Featuretest, the default error handler will be restored.
The default error handler (in libvirtmod.so) just do one thing, it prints the
error message to stderr before we catch the exception in python.

Independent of the error, it will be logged into kimchi error log file.
That way we can easily debug the system.

Signed-off-by: apporc <appleorchard2000 at gmail.com>
Signed-off-by: Aline Manera <alinefm at br.ibm.com>
---
 src/kimchi/featuretests.py |   31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/kimchi/featuretests.py b/src/kimchi/featuretests.py
index 1557dd9..d924050 100644
--- a/src/kimchi/featuretests.py
+++ b/src/kimchi/featuretests.py
@@ -32,6 +32,7 @@ from lxml.builder import E
 
 
 from kimchi import config
+from kimchi.utils import kimchi_log
 
 
 ISO_STREAM_XML = """
@@ -60,17 +61,39 @@ ISO_STREAM_XML = """
 class FeatureTests(object):
 
     @staticmethod
+    def disable_screen_error_logging():
+        def libvirt_errorhandler(userdata, error):
+            # A libvirt error handler to ignore annoying messages in stderr
+            pass
+
+        # Register the error handler to hide libvirt error in stderr
+        libvirt.registerErrorHandler(f=libvirt_errorhandler, ctx=None)
+        # Disable cherrypy screen logging, in order to log errors on kimchi
+        # file without displaying them on screen
+        cherrypy.log.screen = False
+
+    @staticmethod
+    def enable_screen_error_logging():
+        # Unregister the error handler
+        libvirt.registerErrorHandler(f=None, ctx=None)
+        # Enable cherrypy screen logging
+        cherrypy.log.screen = True
+
+    @staticmethod
     def libvirt_supports_iso_stream(protocol):
         xml = ISO_STREAM_XML % {'protocol': protocol}
         conn = None
         try:
+            FeatureTests.disable_screen_error_logging()
             conn = libvirt.open('qemu:///system')
             dom = conn.defineXML(xml)
             dom.undefine()
             return True
-        except libvirt.libvirtError:
+        except libvirt.libvirtError, e:
+            kimchi_log.error(e.message)
             return False
         finally:
+            FeatureTests.enable_screen_error_logging()
             conn is None or conn.close()
 
     @staticmethod
@@ -81,14 +104,18 @@ class FeatureTests(object):
             return xml
         try:
             conn = libvirt.open('qemu:///system')
-            ret = conn.findStoragePoolSources('netfs', _get_xml(), 0)
+            FeatureTests.disable_screen_error_logging()
+            conn.findStoragePoolSources('netfs', _get_xml(), 0)
         except libvirt.libvirtError as e:
+            kimchi_log.error(e.message)
             if e.get_error_code() == 38:
                 # if libvirt cannot find showmount,
                 # it returns 38--general system call failure
                 return False
         finally:
+            FeatureTests.enable_screen_error_logging()
             conn is None or conn.close()
+
         return True
 
     @staticmethod
-- 
1.7.10.4