Hint about broken overlay catalog

4 files changed, 58 insertions, 11 deletions

diff --git a/CHANGES b/CHANGES
index e2f94a6..8a76df1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -6,6 +6,8 @@ Version TODO
 
  - Fix syncing of tar overlays (bug #304547)
 
+ - Hint about broken overlay catalog (bug #304781)
+
 
 Version 1.3.1 - Released 2010/02/05
 ===================================
diff --git a/layman/action.py b/layman/action.py
index b8a9c27..a393167 100644
--- a/layman/action.py
+++ b/layman/action.py
@@ -26,7 +26,7 @@ __version__ = "$Id: action.py 312 2007-04-09 19:45:49Z wrobel $"
 
 import os, sys
 
-from   layman.dbbase            import UnknownOverlayException
+from   layman.dbbase            import UnknownOverlayException, BrokenOverlayCatalog
 from   layman.db                import DB, RemoteDB
 from   layman.utils             import path, delete_empty_directory
 from   layman.debug             import OUT
@@ -66,7 +66,7 @@ class Fetch:
     '''
 
     def __init__(self, config):
-        self.db = RemoteDB(config)
+        self.db = RemoteDB(config, ignore_init_read_errors=True)
 
     def run(self):
         '''Fetch the overlay listing.'''
@@ -544,7 +544,12 @@ def main(config):
             OUT.debug('Checking for action', 7)
 
             if i[0] in config.keys():
-                result += i[1](config).run()
+                try:
+                    result += i[1](config).run()
+                except Exception, error:
+                    OUT.error(str(error))
+                    result = -1  # So it cannot remain 0, i.e. success
+                    break
 
         # Reset umask
         os.umask(old_umask)
diff --git a/layman/db.py b/layman/db.py
index 2a95f47..cdaeb62 100644
--- a/layman/db.py
+++ b/layman/db.py
@@ -62,6 +62,10 @@ class DB(DbBase):
 
         OUT.debug('DB handler initiated', 6)
 
+    # overrider
+    def _broken_catalog_hint(self):
+        return ''
+
     def add(self, overlay, quiet = False):
         '''
         Add an overlay to the local list of overlays.
@@ -210,7 +214,7 @@ class DB(DbBase):
 class RemoteDB(DbBase):
     '''Handles fetching the remote overlay list.'''
 
-    def __init__(self, config):
+    def __init__(self, config, ignore_init_read_errors=False):
 
         self.config = config
 
@@ -237,7 +241,11 @@ class RemoteDB(DbBase):
 
         quiet = int(config['quietness']) < 3
 
-        DbBase.__init__(self, paths, config, ignore, quiet)
+        DbBase.__init__(self, paths, config, ignore, quiet, ignore_init_read_errors)
+
+    # overrider
+    def _broken_catalog_hint(self):
+        return 'Try running "sudo layman -f" to re-fetch that file'
 
     def cache(self):
         '''
@@ -292,7 +300,7 @@ class RemoteDB(DbBase):
                 # Before we overwrite the old cache, check that the downloaded
                 # file is intact and can be parsed
                 try:
-                    self.read(olist)
+                    self.read(olist, origin=url)
                 except Exception, error:
                     raise IOError('Failed to parse the overlays list fetched fr'
                                   'om ' + url + '\nThis means that the download'
diff --git a/layman/dbbase.py b/layman/dbbase.py
index d8aa401..88916ae 100644
--- a/layman/dbbase.py
+++ b/layman/dbbase.py
@@ -29,6 +29,7 @@ __version__ = "$Id: overlay.py 273 2006-12-30 15:54:50Z wrobel $"
 #-------------------------------------------------------------------------------
 
 import sys, os, os.path
+import xml
 import xml.etree.ElementTree as ET # Python 2.5
 
 from   layman.debug              import OUT
@@ -46,6 +47,23 @@ class UnknownOverlayException(Exception):
         message = 'Overlay "%s" does not exist.' % repo_name
         super(UnknownOverlayException, self).__init__(message)
 
+#===============================================================================
+#
+# Class BrokenOverlayCatalog
+#
+#-------------------------------------------------------------------------------
+
+class BrokenOverlayCatalog(ValueError):
+    def __init__(self, origin, expat_error, hint=None):
+        if hint == None:
+            hint = ''
+        else:
+            hint = '\nHint: %s' % hint
+
+        super(BrokenOverlayCatalog, self).__init__(
+            'XML parsing failed for "%(origin)s" (line %(line)d, column %(column)d)%(hint)s' % \
+            {'line':expat_error.lineno, 'column':expat_error.offset + 1, 'origin':origin, 'hint':hint})
+
 
 #===============================================================================
 #
@@ -56,7 +74,7 @@ class UnknownOverlayException(Exception):
 class DbBase:
     ''' Handle a list of overlays.'''
 
-    def __init__(self, paths, config, ignore = 0, quiet = False):
+    def __init__(self, paths, config, ignore = 0, quiet = False, ignore_init_read_errors=False):
 
         self.config = config
         self.quiet = quiet
@@ -68,8 +86,13 @@ class DbBase:
         OUT.debug('Initializing overlay list handler', 8)
 
         for path in self.paths:
-            if os.path.exists(path):
+            if not os.path.exists(path):
+                continue
+
+            try:
                 self.read_file(path)
+            except Exception, error:
+                if not ignore_init_read_errors: raise error
 
     def __eq__(self, other):
         for key in set(self.overlays.keys() + other.overlays.keys()):
@@ -90,9 +113,14 @@ class DbBase:
             raise IOError('Failed to read the overlay list at ("'
                           + path + '")!\nError was:\n' + str(error))
 
-        self.read(document)
+        self.read(document, origin=path)
 
-    def read(self, text):
+    def _broken_catalog_hint(self):
+        this_function_name = sys._getframe().f_code.co_name
+        raise NotImplementedError('Method "%s.%s" not implemented' % \
+                (self.__class__.__name__, this_function_name))
+
+    def read(self, text, origin):
         '''
         Read an xml list of overlays (adding to and potentially overwriting existing entries)
 
@@ -105,7 +133,11 @@ class DbBase:
         >>> list(a.overlays['wrobel-stable'].source_uris())
         [u'rsync://gunnarwrobel.de/wrobel-stable']
         '''
-        document = ET.fromstring(text)
+        try:
+            document = ET.fromstring(text)
+        except xml.parsers.expat.ExpatError, error:
+            raise BrokenOverlayCatalog(origin, error, self._broken_catalog_hint())
+
         overlays = document.findall('overlay') + \
                 document.findall('repo')