Detect required changes for files.

object_types.py

@@ -1,6 +1,10 @@
+import os
+import grp
+import pwd
+from pathlib import Path, PurePath
+import stat
 
-
-class BaseManager:
+class ManagedBase:
     """
     Define allowed/expected fields for configuration object types.
     """
@@ -22,16 +26,77 @@ def validate(self):
 
     def changes_required(self) -> bool:
         """Determine whether applying this manager will cause a change."""
+        return False
+
+    def apply(self) -> bool:
+        """Apply this managed configuration to the system. Idempotent."""
+        return True
 
-class Dummy(BaseManager):
+class Dummy(ManagedBase):
     pass
 
-class TestExample(BaseManager):
+class TestExample(ManagedBase):
     fields = ['test1', 'test2']
 
-class ManagedFile(BaseManager):
+class ManagedFile(ManagedBase):
     fields = ['path', 'name', 'permissions', 'owner', 'group', 'content']
 
-class ManagedPackage(BaseManager):
-    pass
+    def changes_required(self):
+        found_change = False
+        base_path = Path(self.config['path'])
+        file_path = Path(PurePath(self.config['path']).joinpath(self.config['name']))
+        if not base_path.is_dir():
+            print('Directory does not exist')
+            return True
+        if not file_path.is_file():
+            print('File does not exist.')
+            return True
+        with open(file_path, 'r') as f:
+            c = f.read()
+            if c != self.config['content']:
+                print('Content mismatch')
+                found_change = True
+
+        stat_info = os.stat(file_path)
+        mode = stat_info.st_mode
+        uid = stat_info.st_uid
+        gid = stat_info.st_gid
+        # Check permissions
+        file_mode = oct(stat.S_IMODE(mode))[2:]
+        if file_mode != self.config['permissions']:
+            print('File mode incorrect. Current: {} Expected: {}'.format(file_mode, self.config['permissions']))
+            found_change = True
+
+        # Check owner and group
+        owner = pwd.getpwuid(uid)[0]
+        group = grp.getgrgid(gid)[0]
+        if owner != self.config['owner']:
+            print("Owner incorrect. Current: {}, Expected: {}".format(owner, self.config['owner']))
+            found_change = True
+        if group != self.config['group']:
+            print("Group incorrect. Current: {}, Expected: {}".format(group, self.config['group']))
+            found_change = True
+        return found_change
 
+
+class ManagedPackage(ManagedBase):
+    fields = ['name', 'version']
+    def changes_required(self):
+        # sudo apt-get update
+        # sudo dpkg -s <name>
+        # find "Status: install ok installed" or similar in output
+        # find version in output, eg "Version: 2.4.29-1ubuntu4.6"
+        pass
+
+class ManagedService(ManagedBase):
+    fields = ['name', 'state']
+
+    def validate(self):
+        super(ManagedService, self).validate()
+        valid_states = ['running', 'stopped']
+        if self.config['state'] not in valid_states:
+            raise(Exception("Field 'state' must be one of {}").format(valid_states))
+
+    def changes_required(self):
+        "sudo service <name> status"
+        "systemctl status <name>"