slapos/grid: improve logging regarding networkcache

slapos/grid/SlapObject.py

@@ -213,6 +213,9 @@ class Software(object):
         finally:
           tar.close()
       elif force_binary_cache:
+        if os.path.exists(self.software_path):
+          message = 'Binary cache forced for %r, but directory %s already exists, will retry again' % (self.url, self.software_path)
+        else:
           message = 'Binary cache forced for %r, but failed to download, will retry again' % (self.url,)
         self.logger.error(message)
         raise BuildoutFailedError(message)

slapos/grid/networkcache.py

@@ -93,13 +93,16 @@ def download_network_cached(cache_url, dir_url, software_url, software_root,
     return True if download succeeded.
     """
     if not LIBNETWORKCACHE_ENABLED:
+      logger.warning('LIBNETWORKCACHE_ENABLED is false')
       return False
 
     if not(cache_url and dir_url and software_url and software_root):
+      logger.warning('networkcache badly configured')
       return False
 
     for url in download_from_binary_cache_url_blacklist:
       if software_url.startswith(url):
+        logger.warning('URL %s is blacklisted', url)
         return False
 
     try: