We must close the HTTP connection after calling the getresponse method.

Otherwise, all the connections would still alive and this is not a good
behavior.

Once we need to close the connections it is not possible to return the
content of getresponse method, the method read would return an empty
string instead of the correct data.

And also the data returned by shadir is a json content,
to reach a better usage of libnetworkcache the data returned must be
loaded by json library, in other words, it must be a list.

slapos/libnetworkcache/__init__.py

@@ -87,13 +87,17 @@ class NetworkcacheClient(object):
     sha512sum = hashlib.sha512(file_content).hexdigest()
     path = os.path.join(self.shacache_path, sha512sum)
 
-    self.shacache_connection = httplib.HTTPConnection(self.shacache_host)
-    self.shacache_connection.request('POST', path, file_content,
+    shacache_connection = httplib.HTTPConnection(self.shacache_host)
+    try:
+      shacache_connection.request('POST', path, file_content,
                                                  self.shacache_header_dict)
-    result = self.shacache_connection.getresponse()
+      result = shacache_connection.getresponse()
+      data = result.read()
+    finally:
+      shacache_connection.close()
 
     if result.status != 200:
-      return result
+      raise UploadError('Failed to upload. Response code: %s. Response data: %s' % (result.status, data))
 
     if directory_key is not None:
       path = os.path.join(self.shadir_path, directory_key)
@@ -111,23 +115,34 @@ class NetworkcacheClient(object):
         signature = "SIGNATURE"
       data = [kw, signature]
 
-      self.shadir_connection = httplib.HTTPConnection(self.shadir_host)
-      self.shadir_connection.request('POST', path, json.dumps(data),
+      shadir_connection = httplib.HTTPConnection(self.shadir_host)
+      try:
+        shadir_connection.request('POST', path, json.dumps(data),
                                                  self.shadir_header_dict)
-      result = self.shadir_connection.getresponse()
-    return result
+        result = shadir_connection.getresponse()
+        data = result.read()
+      finally:
+        shadir_connection.close()
+
+    return json.loads(data)
 
   def download(self, sha512sum):
     ''' Download the file.
     It uses http GET request method.
     '''
     path_info = os.path.join(self.shacache_path, sha512sum)
-    self.shacache_connection = httplib.HTTPConnection(self.shacache_host)
-    self.shacache_connection.request('GET', path_info, headers=self.shacache_header_dict)
-    result = self.shacache_connection.getresponse()
+    shacache_connection = httplib.HTTPConnection(self.shacache_host)
+    try:
+      shacache_connection.request('GET', path_info, headers=self.shacache_header_dict)
+      result = shacache_connection.getresponse()
+      file_content = result.read()
+    finally:
+      shacache_connection.close()
+
     if result.status != 200:
       raise FileNotFound(result.read())
-    return result
+
+    return file_content
 
   def select(self, directory_key=None):
     '''Download a file from shacache by selecting the entry in shadir
@@ -137,22 +152,18 @@ class NetworkcacheClient(object):
     if directory_key is not None:
       path_info = os.path.join(self.shadir_path, directory_key)
 
-    self.shadir_connection = httplib.HTTPConnection(self.shadir_host)
-    self.shadir_connection.request('GET', path_info, headers=self.shadir_header_dict)
-    result = self.shadir_connection.getresponse()
+    shadir_connection = httplib.HTTPConnection(self.shadir_host)
+    try:
+      shadir_connection.request('GET', path_info, headers=self.shadir_header_dict)
+      result = shadir_connection.getresponse()
+      data = result.read()
+    finally:
+      shadir_connection.close()
+
     if result.status != 200:
       raise DirectoryNotFound(result.read())
-    data = json.loads(result.read())
-    self.close()
-    return data
-
-  def close(self):
-    ''' It must be called to close the HTTP Connection. '''
-    if hasattr(self, 'shacache_connection'):
-      self.shacache_connection.close()
 
-    if hasattr(self, 'shadir_connection'):
-      self.shadir_connection.close()
+    return json.loads(data)
 
 
 class FileNotFound(Exception):