Call the method get_sha256sum_from_networkcached into download_network_cached....

Call the method get_sha256sum_from_networkcached into download_network_cached. If the sha256sum does not exists on networkcached server it should return False.
Signed-off-by: Lucas Carvalho <lucas@nexedi.com>

src/zc/buildout/networkcache.py

@@ -105,12 +105,13 @@ def get_sha256sum_from_networkcached(network_cache, url, logger):
         result = urllib.urlopen(network_cached_url)
         if int(result.code) == 200:
           return json.loads(result.read().strip()).get('sha256sum', None)
+        logger.info('The url is not cached yet: %s' % url)
     except IOError, e:
         logger.info('An error occurred to get sha256sum from networkcached:' \
                                                                ' %s' % str(e))
 
 
-def download_network_cached(network_cache, path, logger):
+def download_network_cached(network_cache, path, url, logger):
     """Download from a network cache provider
 
     If something fail (providor be offline, or hash_string fail), we ignore
@@ -122,19 +123,21 @@ def download_network_cached(network_cache, path, logger):
         # Not able to use network cache
         return False
 
-    sha256sum = get_sha256sum_from_networkcached(network_cache,
-                                                 url,
-                                                 self.logger)
+    sha256sum = get_sha256sum_from_networkcached(network_cache, url, logger)
+    if sha256sum is None:
+      return False
 
-    url = os.path.join(network_cache, sha256sum)
-    logger.info('Downloading from network cache %s' % url)
+    network_cached_url = os.path.join(network_cache, sha256sum)
+    logger.info('Downloading from network cache %s' % network_cached_url)
     try:
-        path, headers = urllib.urlretrieve(url, path)
+        path, headers = urllib.urlretrieve(network_cached_url, path)
         if not check_sha256sum(path, sha256sum):
-            logger.info('MD5/SHA256 checksum mismatch downloading %r' % url)
+            logger.info('MD5/SHA256 checksum mismatch downloading %r' % \
+                                                           network_cached_url)
             return False
     except IOError, e:
-        logger.info('Fail to download from network cache %s' % url)
+        logger.info('Fail to download from network cache %s' % \
+                                                           network_cached_url)
         return False
 
     return True
@@ -190,12 +193,7 @@ def fetch_from_network_cache(network_cache, location, tmp, logger=None):
     filename = _get_filename_from_url(location)
     path = os.path.join(tmp, filename)
 
-    sha256sum = get_sha256sum_from_networkcached(network_cache,
-                                                 location, logger)
-    if sha256sum is None:
-      return None
-
-    is_downloaded = download_network_cached(network_cache, path, sha256sum, logger)
+    is_downloaded = download_network_cached(network_cache, path, location, logger)
     if is_downloaded:
         return path