[sonic-yang-mgmt]: Resolving LGTM.

Changes:
To address 'import *' related LGTM alerts
1.) Moved all functions of _sonic_yang_ext.py file in sonic_yang_ext_mixin class.
2.) Use this class in sonic_yang to extend funtionality, i.e. python mixin.

Note: Python mixin are different from parent class since it can access all variables
of the class which is using it.

Other LGTM issues
3.) Address Other LGTM minor issues found in below link.
https://lgtm.com/projects/g/Azure/sonic-buildimage/rev/pr-0f82616403c02577e1155347eb5b693a51c76a9e

Signed-off-by: Praveen Chaudhary pchaudhary@linkedin.com

src/sonic-yang-mgmt/_sonic_yang_ext.py

@@ -3,13 +3,10 @@
 
 import yang as ly
 import re
-import pprint
 import syslog
 
-from json import dump, load, dumps, loads
+from json import dump, dumps, loads
 from xmltodict import parse
-from os import listdir, walk, path
-from os.path import isfile, join, splitext
 from glob import glob
 
 # class sonic_yang methods, use mixin to extend sonic_yang
@@ -168,7 +165,7 @@ def extractKey(self, tableKey, keys, regex):
     """
     def fillLeafDict(self, leafs, leafDict, isleafList=False):
 
-        if leafs == None:
+        if leafs is None:
             return
 
         # fill default values
@@ -645,16 +642,16 @@ def delete_node(self, xpath):
                     nodeP = self.find_parent_node(xpath)
                     xpathP = nodeP.path()
                     if self._delete_node(xpath=xpathP, node=nodeP) == False:
-                        raise('_delete_node failed')
+                        raise Exception('_delete_node failed')
                     else:
                         return True
 
             # delete non key element
             if self._delete_node(xpath=xpath, node=node) == False:
-                raise('_delete_node failed')
+                raise Exception('_delete_node failed')
         except Exception as e:
             print(e)
-            raise('Failed to delete node {}'.format(xpath))
+            raise Exception('Failed to delete node {}'.format(xpath))
 
         return True
 

src/sonic-yang-mgmt/setup.py

@@ -5,22 +5,21 @@
 
 from setuptools import setup, find_packages
 from setuptools.command.build_py import build_py
-from os import system
+from os import system, environ
 from sys import exit
 import pytest
-import os
 
 # find path of pkgs from os environment vars
-prefix = '/sonic'; debs = os.environ["STRETCH_DEBS_PATH"]
-wheels = os.environ["PYTHON_WHEELS_PATH"]
+prefix = '/sonic'; debs = environ["STRETCH_DEBS_PATH"]
+wheels = environ["PYTHON_WHEELS_PATH"]
 wheels_path = '{}/{}'.format(prefix, wheels)
 deps_path = '{}/{}'.format(prefix, debs)
 # dependencies
-libyang = '{}/{}'.format(deps_path, os.environ["LIBYANG"])
-libyangCpp = '{}/{}'.format(deps_path, os.environ["LIBYANG_CPP"])
-libyangPy2 = '{}/{}'.format(deps_path, os.environ["LIBYANG_PY2"])
-libyangPy3 = '{}/{}'.format(deps_path, os.environ["LIBYANG_PY3"])
-sonicYangModels = '{}/{}'.format(wheels_path, os.environ["SONIC_YANG_MODELS_PY3"])
+libyang = '{}/{}'.format(deps_path, environ["LIBYANG"])
+libyangCpp = '{}/{}'.format(deps_path, environ["LIBYANG_CPP"])
+libyangPy2 = '{}/{}'.format(deps_path, environ["LIBYANG_PY2"])
+libyangPy3 = '{}/{}'.format(deps_path, environ["LIBYANG_PY3"])
+sonicYangModels = '{}/{}'.format(wheels_path, environ["SONIC_YANG_MODELS_PY3"])
 
 # important reuirements parameters
 build_requirements = [libyang, libyangCpp, libyangPy2, libyangPy3, sonicYangModels,]

src/sonic-yang-mgmt/sonic_yang.py

@@ -237,7 +237,7 @@ def validate_data (self, node=None, ctx=None):
             ctx = self.ctx
 
         try:
-            rc = node.validate(ly.LYD_OPT_CONFIG, ctx)
+            node.validate(ly.LYD_OPT_CONFIG, ctx)
         except Exception as e:
             self.fail(e)
 
@@ -374,7 +374,7 @@ def find_data_node_schema_xpath(self, data_xpath):
     """
     def add_data_node(self, data_xpath, value):
         try:
-            data_node = self.new_data_node(data_xpath, value)
+            self.new_node(xpath, value)
             #check if the node added to the data tree
             self.find_data_node(data_xpath)
         except Exception as e:
@@ -452,7 +452,7 @@ def find_data_node_value(self, data_xpath):
     """
     def set_data_node_value(self, data_xpath, value):
         try:
-            data_node = self.root.new_path(self.ctx, data_xpath, str(value), ly.LYD_ANYDATA_STRING, ly.LYD_PATH_OPT_UPDATE)
+            self.root.new_path(self.ctx, data_xpath, str(value), ly.LYD_ANYDATA_STRING, ly.LYD_PATH_OPT_UPDATE)
         except Exception as e:
             print("set data node value failed for xpath: " + str(data_xpath))
             self.fail(e)
@@ -474,7 +474,7 @@ def find_data_nodes(self, data_xpath):
                 raise Exception('data node not found')
 
             for data_set in node_set.data():
-                schema = data_set.schema()
+                data_set.schema()
                 list.append(data_set.path())
             return list
 
@@ -486,7 +486,6 @@ def find_data_nodes(self, data_xpath):
     """
     def find_schema_dependencies (self, schema_xpath):
         ref_list = []
-        node = self.root
         try:
             schema_node = self.find_schema_node(schema_xpath)
         except Exception as e:
@@ -527,7 +526,7 @@ def find_data_dependencies (self, data_xpath):
                 for link in backlinks.schema():
                      node_set = node.find_path(link.path())
                      for data_set in node_set.data():
-                          schema = data_set.schema()
+                          data_set.schema()
                           casted = data_set.subtype()
                           if value == casted.value_str():
                               ref_list.append(data_set.path())
@@ -648,7 +647,7 @@ def get_leafref_type_schema (self, schema_xpath):
                 if subtype.type().base() != ly.LY_TYPE_LEAFREF:
                     return None
                 else:
-                    leafref_path = subtype.type().info().lref().path()
+                    subtype.type().info().lref().path()
                     target = subtype.type().info().lref().target()
                     target_path = target.path()
                     target_type = self.get_data_type(target_path)

src/sonic-yang-mgmt/tests/libyang-python-tests/test_sonic_yang.py

@@ -1,11 +1,8 @@
 import sys
 import os
 import pytest
-import yang as ly
 import sonic_yang as sy
 import json
-import getopt
-import subprocess
 import glob
 import logging
 from ijson import items as ijson_itmes
@@ -31,7 +28,6 @@ def data(self):
     @pytest.fixture(autouse=True, scope='class')
     def yang_s(self, data):
         yang_dir = str(data['yang_dir'])
-        data_file = str(data['data_file'])
         yang_s = sy.sonic_yang(yang_dir)
         return yang_s
 
@@ -62,7 +58,7 @@ def readIjsonInput(self, yang_test_file, test):
             raise(e)
         return jInput
 
-    def setup_class(cls):
+    def setup_class(self):
         pass
 
     def load_yang_model_file(self, yang_s, yang_dir, yang_file, module_name):
@@ -140,14 +136,14 @@ def test_find_node(self, data, yang_s):
                  assert dnode is not None
                  assert dnode.path() == xpath
             else:
-                 assert dnode == None
+                 assert dnode is None
 
     #test add node
     def test_add_node(self, data, yang_s):
         for node in data['new_nodes']:
             xpath = str(node['xpath'])
             value = node['value']
-            status = yang_s.add_data_node(xpath, str(value))
+            yang_s.add_node(xpath, str(value))
 
             data_node = yang_s.find_data_node(xpath)
             assert data_node is not None
@@ -165,7 +161,6 @@ def test_find_data_node_value(self, data, yang_s):
     #test delete data node
     def test_delete_node(self, data, yang_s):
         for node in data['delete_nodes']:
-            expected = node['valid']
             xpath = str(node['xpath'])
             yang_s._delete_node(xpath)
 
@@ -291,5 +286,5 @@ def test_xlate_rev_xlate(self):
 
         return
 
-    def teardown_class(cls):
+    def teardown_class(self):
         pass