Idempotency for net_get and net_put modules (#42307)

* Idempotency for net_get and net_put modules

* pep8 warnings fix

* remove import q

lib/ansible/plugins/action/net_put.py

@@ -21,8 +21,10 @@ import copy
 import os
 import time
 import uuid
+import hashlib
+import sys
 
-from ansible.module_utils._text import to_text
+from ansible.module_utils._text import to_text, to_bytes
 from ansible.module_utils.connection import Connection
 from ansible.errors import AnsibleError
 from ansible.plugins.action import ActionBase
@@ -38,6 +40,7 @@ except ImportError:
 class ActionModule(ActionBase):
 
     def run(self, tmp=None, task_vars=None):
+        changed = True
         socket_path = None
         play_context = copy.deepcopy(self._play_context)
         play_context.network_os = self._get_network_os(task_vars)
@@ -70,7 +73,7 @@ class ActionModule(ActionBase):
         if mode is None:
             mode = 'binary'
 
-        if mode == 'template':
+        if mode == 'text':
             try:
                 self._handle_template()
             except ValueError as exc:
@@ -97,6 +100,17 @@ class ActionModule(ActionBase):
 
         if dest is None:
             dest = src_file_path_name
+
+        try:
+            changed = self._handle_existing_file(conn, output_file, dest, proto, sock_timeout)
+            if changed is False:
+                result['changed'] = False
+                result['destination'] = dest
+                return result
+        except Exception as exc:
+            result['msg'] = ('Warning: Exc %s idempotency check failed. Check'
+                             'dest' % exc)
+
         try:
             out = conn.copy_file(
                 source=output_file, destination=dest,
@@ -112,13 +126,55 @@ class ActionModule(ActionBase):
                 result['failed'] = True
                 result['msg'] = ('Exception received : %s' % exc)
 
-        if mode == 'template':
+        if mode == 'text':
             # Cleanup tmp file expanded wih ansible vars
             os.remove(output_file)
 
-        result['changed'] = True
+        result['changed'] = changed
+        result['destination'] = dest
         return result
 
+    def _handle_existing_file(self, conn, source, dest, proto, timeout):
+        cwd = self._loader.get_basedir()
+        filename = str(uuid.uuid4())
+        source_file = os.path.join(cwd, filename)
+        try:
+            out = conn.get_file(
+                source=dest, destination=source_file,
+                proto=proto, timeout=timeout
+            )
+        except Exception as exc:
+            if (to_text(exc)).find("No such file or directory") > 0:
+                return True
+            else:
+                try:
+                    os.remove(source_file)
+                except OSError as osex:
+                    raise Exception(osex)
+
+        try:
+            with open(source, 'r') as f:
+                new_content = f.read()
+            with open(source_file, 'r') as f:
+                old_content = f.read()
+        except (IOError, OSError) as ioexc:
+            raise IOError(ioexc)
+
+        sha1 = hashlib.sha1()
+        old_content_b = to_bytes(old_content, errors='surrogate_or_strict')
+        sha1.update(old_content_b)
+        checksum_old = sha1.digest()
+
+        sha1 = hashlib.sha1()
+        new_content_b = to_bytes(new_content, errors='surrogate_or_strict')
+        sha1.update(new_content_b)
+        checksum_new = sha1.digest()
+        os.remove(source_file)
+        if checksum_old == checksum_new:
+            return False
+        else:
+            return True
+
     def _get_working_path(self):
         cwd = self._loader.get_basedir()
         if self._task._role is not None: