Fixing Linter errors: undefined-variables<E0602>. (#1999)

* Fixed linter errors for undefined variables.

azurelinuxagent/common/future.py

@@ -25,16 +25,38 @@
 
     bytebuffer = memoryview # pylint: disable=C0103
 
+    # We aren't using these imports in this file, but we want them to be available
+    # to import from this module in others.
+    # Additionally, python2 doesn't have this, so we need to disable import-error
+    # as well.
+    from builtins import int, range # pylint: disable=unused-import,import-error
+
     from collections import OrderedDict # pylint: disable=W0611
 
 elif sys.version_info[0] == 2:
     import httplib as httpclient # pylint: disable=E0401,W0611
     from urlparse import urlparse # pylint: disable=E0401
 
-    """Rename Python2 unicode to ustr""" # pylint: disable=W0105
-    ustr = unicode # pylint: disable=E0602,invalid-name
-
-    bytebuffer = buffer # pylint: disable=E0602,invalid-name
+
+    # We want to suppress the following:
+    #   -   undefined-variable<E0602>: 
+    #           These builtins are not defined in python3
+    #   -   invalid-name<C0103>: 
+    #           The defined variables are constants, but don't use UPPER_SNAKE_CASE 
+    #           as we're redefining some builtins that also do not use that format.
+    #   -   redefined-builtin<W0622>:
+    #           This is intentional, so that code that wants to use builtins we're
+    #           assigning new names to doesn't need to check python versions before
+    #           doing so.
+
+    # pylint: disable=undefined-variable,invalid-name,redefined-builtin
+
+    ustr = unicode # Rename Python2 unicode to ustr 
+    bytebuffer = buffer
+    range = xrange
+    int = long
+
+    # pylint: enable=undefined-variable,invalid-name,redefined-builtin
 
     if sys.version_info[1] >= 7:
         from collections import OrderedDict  # For Py 2.7+ # pylint: disable=C0412

azurelinuxagent/common/osutil/clearlinux.py

@@ -26,12 +26,14 @@
 import fcntl # pylint: disable=W0611
 import time # pylint: disable=W0611
 import base64 # pylint: disable=W0611
+import errno
 import azurelinuxagent.common.conf as conf
 import azurelinuxagent.common.logger as logger # pylint: disable=W0611
 import azurelinuxagent.common.utils.fileutil as fileutil
 import azurelinuxagent.common.utils.shellutil as shellutil
 import azurelinuxagent.common.utils.textutil as textutil # pylint: disable=W0611
 from azurelinuxagent.common.osutil.default import DefaultOSUtil
+from azurelinuxagent.common.exception import OSUtilError
 
 class ClearLinuxUtil(DefaultOSUtil):
 
@@ -79,14 +81,16 @@ def del_root_password(self):
                 passwd_content = fileutil.read_file(passwd_file_path)
                 if not passwd_content:
                     # Empty file is no better than no file
-                    raise FileNotFoundError # pylint: disable=undefined-variable
-            except FileNotFoundError: # pylint: disable=undefined-variable
+                    raise IOError(errno.ENOENT, "Empty File", passwd_file_path)
+            except (IOError, OSError) as file_read_err:
+                if file_read_err.errno != errno.ENOENT:
+                    raise
                 new_passwd = ["root:*LOCK*:14600::::::"]
             else:
                 passwd = passwd_content.split('\n')
                 new_passwd = [x for x in passwd if not x.startswith("root:")]
                 new_passwd.insert(0, "root:*LOCK*:14600::::::")
             fileutil.write_file(passwd_file_path, "\n".join(new_passwd))
         except IOError as e: # pylint: disable=C0103
-            raise OSUtilError("Failed to delete root password:{0}".format(e)) # pylint: disable=E0602
+            raise OSUtilError("Failed to delete root password:{0}".format(e))
         pass # pylint: disable=W0107

azurelinuxagent/common/osutil/gaia.py

@@ -23,7 +23,7 @@
 
 import azurelinuxagent.common.conf as conf
 from azurelinuxagent.common.exception import OSUtilError
-from azurelinuxagent.common.future import ustr, bytebuffer
+from azurelinuxagent.common.future import ustr, bytebuffer, range, int # pylint: disable=redefined-builtin
 import azurelinuxagent.common.logger as logger
 from azurelinuxagent.common.osutil.default import DefaultOSUtil
 from azurelinuxagent.common.utils.cryptutil import CryptUtil
@@ -40,7 +40,7 @@ def __init__(self): # pylint: disable=W0235
     def _run_clish(self, cmd):
         ret = 0
         out = ""
-        for i in xrange(10): # pylint: disable=E0602,W0612
+        for i in range(10): # pylint: disable=W0612
             try:
                 final_command = ["/bin/clish", "-s", "-c", "'{0}'".format(cmd)]
                 out = shellutil.run_command(final_command, log_error=True)
@@ -122,7 +122,7 @@ def openssl_to_openssh(self, input_file, output_file):
         def text_to_num(buf):
             if len(buf) == 1:
                 return int(buf[0].split()[1])
-            return long(''.join(buf[1:]), 16) # pylint: disable=E0602
+            return int(''.join(buf[1:]), 16)
 
         n = text_to_num(modulus) # pylint: disable=C0103
         e = text_to_num(exponent) # pylint: disable=C0103

azurelinuxagent/common/osutil/iosxe.py

@@ -17,12 +17,13 @@
 # Requires Python 2.6+ and Openssl 1.0+
 #
 
+import os
+
 import azurelinuxagent.common.logger as logger
 import azurelinuxagent.common.utils.shellutil as shellutil
 from azurelinuxagent.common.future import ustr
-from azurelinuxagent.common.osutil.default import DefaultOSUtil
-from azurelinuxagent.common.osutil.redhat import Redhat6xOSUtil # pylint: disable=W0611
-from azurelinuxagent.common.utils import textutil # pylint: disable=W0611
+from azurelinuxagent.common.osutil.default import DefaultOSUtil, PRODUCT_ID_FILE, DMIDECODE_CMD, UUID_PATTERN
+from azurelinuxagent.common.utils import textutil, fileutil # pylint: disable=W0611
 
 # pylint: disable=W0105
 '''
@@ -58,7 +59,7 @@ def publish_hostname(self, hostname):
         Restart NetworkManager first before publishing hostname
         """
         shellutil.run("service NetworkManager restart")
-        super(RedhatOSUtil, self).publish_hostname(hostname) # pylint: disable=E0602
+        super(IosxeOSUtil, self).publish_hostname(hostname)
 
     def register_agent_service(self):
         return shellutil.run("systemctl enable waagent", chk_err=False)
@@ -79,13 +80,13 @@ def get_instance_id(self):
         If that is missing, then extracts from dmidecode
         If nothing works (for old VMs), return the empty string
         '''
-        if os.path.isfile(PRODUCT_ID_FILE): # pylint: disable=E0602
+        if os.path.isfile(PRODUCT_ID_FILE):
             try:
-                s = fileutil.read_file(PRODUCT_ID_FILE).strip() # pylint: disable=E0602,C0103
+                s = fileutil.read_file(PRODUCT_ID_FILE).strip() # pylint: disable=C0103
                 return self._correct_instance_id(s.strip())
             except IOError:
                 pass
-        rc, s = shellutil.run_get_output(DMIDECODE_CMD) # pylint: disable=E0602,C0103
-        if rc != 0 or UUID_PATTERN.match(s) is None: # pylint: disable=E0602
+        rc, s = shellutil.run_get_output(DMIDECODE_CMD) # pylint: disable=C0103
+        if rc != 0 or UUID_PATTERN.match(s) is None:
             return ""
         return self._correct_instance_id(s.strip())

azurelinuxagent/common/osutil/openwrt.py

@@ -126,7 +126,7 @@ def restart_ssh_service(self): # pylint: disable=R1710
         if os.path.exists("/etc/init.d/sshd"): # pylint: disable=R1705
             return shellutil.run("/etc/init.d/sshd restart", chk_err=True)
         else:
-            logger.warn("sshd service does not exists", username) # pylint: disable=E0602
+            logger.warn("sshd service does not exists")
 
     def stop_agent_service(self):
         return shellutil.run("/etc/init.d/{0} stop".format(self.service_name), chk_err=True)

azurelinuxagent/daemon/resourcedisk/openwrt.py

@@ -18,7 +18,7 @@
 # Requires Python 2.6+ and Openssl 1.0+
 #
 import os
-import errno as errno # pylint: disable=C0414,W0611
+from time import sleep
 
 import azurelinuxagent.common.logger as logger
 import azurelinuxagent.common.utils.fileutil as fileutil
@@ -94,7 +94,7 @@ def mount_resource_disk(self, mount_point): # pylint: disable=R0914
             logger.info("Waiting for partition [{0}], {1} attempts remaining",
                         partition,
                         attempts)
-            sleep(5) # pylint: disable=E0602
+            sleep(5)
             attempts -= 1
 
         if not os.path.exists(partition):

azurelinuxagent/pa/deprovision/default.py

@@ -38,6 +38,9 @@ def read_input(message):
     if sys.version_info[0] >= 3: # pylint: disable=R1705
         return input(message)
     else:
+        # This is not defined in python3, and the linter will thus 
+        # throw an undefined-variable<E0602> error on this line.
+        # Suppress it here.
         return raw_input(message) # pylint: disable=E0602
 
 class DeprovisionAction(object): # pylint: disable=R0903

ci/2.7.pylintrc

@@ -47,7 +47,6 @@
 # too-many-nested-blocks<R1702>: Used when a function or a method has too many nested blocks. 
 # too-many-public-methods<R0904>: Used when class has too many public methods, try to reduce this to get a simpler (and so easier to use) class.
 # too-many-return-statements<R0911>: Used when a function or method has too many return statement, making it hard to follow.
-# undefined-variable<E0602>: (hi-pri) Used when an undefined variable is accessed.
 # ungrouped-imports<C0412>: (needs review) Used when imports are not grouped by packages
 # unidiomatic-typecheck<C0123>: (hi-pri) The idiomatic way to perform an explicit typecheck in Python is to use isinstance(x, Y) rather than type(x) == Y, type(x) is Y.
 # unnecessary-lambda<W0108>: Used when the body of a lambda expression is a function call on the same argument list as the lambda itself

ci/3.6.pylintrc

@@ -58,7 +58,6 @@
 # too-many-nested-blocks<R1702>: Used when a function or a method has too many nested blocks. 
 # too-many-public-methods<R0904>: Used when class has too many public methods, try to reduce this to get a simpler (and so easier to use) class.
 # too-many-return-statements<R0911>: Used when a function or method has too many return statement, making it hard to follow.
-# undefined-variable<E0602>: (hi-pri) Used when an undefined variable is accessed.
 # ungrouped-imports<C0412>: (needs review) Used when imports are not grouped by packages
 # unidiomatic-typecheck<C0123>: (hi-pri) The idiomatic way to perform an explicit typecheck in Python is to use isinstance(x, Y) rather than type(x) == Y, type(x) is Y.
 # unnecessary-comprehension<R1721>: (hi-pri) Instead of using an identity comprehension, consider using the list, dict or set constructor.

tests/protocol/test_hostplugin.py

@@ -27,7 +27,7 @@
 import azurelinuxagent.common.protocol.wire as wire
 from azurelinuxagent.common.errorstate import ErrorState
 from azurelinuxagent.common.exception import HttpError, ResourceGoneError
-from azurelinuxagent.common.future import ustr
+from azurelinuxagent.common.future import ustr, httpclient
 from azurelinuxagent.common.osutil.default import UUID_PATTERN
 from azurelinuxagent.common.protocol.hostplugin import API_VERSION
 from azurelinuxagent.common.utils import restutil
@@ -37,13 +37,6 @@
 from tests.protocol.test_wire import MockResponse as TestWireMockResponse
 from tests.tools import AgentTestCase, PY_VERSION_MAJOR, Mock, patch
 
-if sys.version_info[0] == 3:
-    import http.client as httpclient # pylint: disable=import-error
-    bytebuffer = memoryview # pylint: disable=invalid-name
-elif sys.version_info[0] == 2:
-    import httplib as httpclient # pylint: disable=import-error
-    bytebuffer = buffer # pylint: disable=undefined-variable,invalid-name
-
 
 hostplugin_status_url = "http://168.63.129.16:32526/status" # pylint: disable=invalid-name
 hostplugin_versions_url = "http://168.63.129.16:32526/versions" # pylint: disable=invalid-name

tests/tools.py

@@ -34,10 +34,8 @@
 import azurelinuxagent.common.conf as conf
 import azurelinuxagent.common.event as event
 import azurelinuxagent.common.logger as logger
+from azurelinuxagent.common.future import range # pylint: disable=redefined-builtin
 from azurelinuxagent.common.cgroupapi import SYSTEMD_RUN_PATH
-from azurelinuxagent.common.cgroupconfigurator import CGroupConfigurator # pylint: disable=unused-import
-from azurelinuxagent.common.osutil.factory import _get_osutil # pylint: disable=unused-import
-from azurelinuxagent.common.osutil.ubuntu import Ubuntu14OSUtil, Ubuntu16OSUtil # pylint: disable=unused-import
 from azurelinuxagent.common.utils import fileutil
 from azurelinuxagent.common.version import PY_VERSION_MAJOR
 
@@ -359,7 +357,7 @@ def emulate_assertListEqual(self, seq1, seq2, msg=None, seq_type=None): # pylint
             elements = (seq_type_name.capitalize(), seq1_repr, seq2_repr)
             differing = '%ss differ: %s != %s\n' % elements
 
-            for i in xrange(min(len1, len2)): # pylint: disable=undefined-variable
+            for i in range(min(len1, len2)):
                 try:
                     item1 = seq1[i]
                 except (TypeError, IndexError, NotImplementedError):