Add ability to uninstall service

src/primaite/simulator/file_system/file_system.py

@@ -1,5 +1,5 @@
 from random import choice
-from typing import Dict, Optional
+from typing import Dict, Optional, Union
 
 from primaite import getLogger
 from primaite.simulator.core import SimComponent
@@ -211,7 +211,7 @@ class FileSystem(SimComponent):
             if file is not None:
                 return file
 
-    def get_folder_by_name(self, folder_name: str) -> FileSystemFolder:
+    def get_folder_by_name(self, folder_name: str) -> Union[FileSystemFolder, None]:
         """
         Returns a the first folder with a matching name.
 

src/primaite/simulator/network/hardware/base.py

@@ -1004,6 +1004,7 @@ class Node(SimComponent):
         if service in self:
             _LOGGER.warning(f"Can't add service {service.uuid} to node {self.uuid}. It's already installed.")
             return
+        self.services[service.uuid] = service
         service.parent = self
         service.install()  # Perform any additional setup, such as creating files for this service on the node.
         _LOGGER.info(f"Added service {service.uuid} to node {self.uuid}")

src/primaite/simulator/system/services/database.py

@@ -12,6 +12,21 @@ class DatabaseService(Service):
         """TODO."""
         return super().describe_state()
 
+    def uninstall(self) -> None:
+        """
+        Undo installation procedure.
+
+        This method deletes files created when installing the database, and the database folder if it is empty.
+        """
+        super().uninstall()
+        node: Node = self.parent
+        node.file_system.delete_file(self.primary_store)
+        node.file_system.delete_file(self.transaction_log)
+        if self.secondary_store:
+            node.file_system.delete_file(self.secondary_store)
+        if len(self.folder.files) == 0:
+            node.file_system.delete_folder(self.folder)
+
     def install(self) -> None:
         """Perform first time install on a node, creating necessary files."""
         super().install()
@@ -39,10 +54,16 @@ class DatabaseService(Service):
         # note that this parent.file_system.create_folder call in the future will be authenticated by using permissions
         # handler. This permission will be granted based on service account given to the database service.
         self.parent: Node
-        folder = self.parent.file_system.create_folder(folder_name)
+        self.folder = self.parent.file_system.create_folder(folder_name)
-        self.parent.file_system.create_file("db_primary_store", db_size, FileSystemFileType.MDF, folder=folder)
+        self.primary_store = self.parent.file_system.create_file(
-        self.parent.file_system.create_file("db_transaction_log", "1", FileSystemFileType.LDF, folder=folder)
+            "db_primary_store", db_size, FileSystemFileType.MDF, folder=self.folder
+        )
+        self.transaction_log = self.parent.file_system.create_file(
+            "db_transaction_log", "1", FileSystemFileType.LDF, folder=self.folder
+        )
         if use_secondary_db_file:
-            self.parent.file_system.create_file(
+            self.secondary_store = self.parent.file_system.create_file(
-                "db_secondary_store", secondary_db_size, FileSystemFileType.NDF, folder=folder
+                "db_secondary_store", secondary_db_size, FileSystemFileType.NDF, folder=self.folder
             )
+        else:
+            self.secondary_store = None

src/primaite/simulator/system/software.py

@@ -1,13 +1,10 @@
 from abc import abstractmethod
 from enum import Enum
-from typing import Any, Dict, Set, TYPE_CHECKING
+from typing import Any, Dict, Set
 
 from primaite.simulator.core import Action, ActionManager, SimComponent
 from primaite.simulator.network.transmission.transport_layer import Port
 
-if TYPE_CHECKING:
-    from primaite.simulator.network.hardware.base import Node
-
 
 class SoftwareType(Enum):
     """
@@ -143,11 +140,17 @@ class Software(SimComponent):
         This is an abstract class that should be overwritten by specific applications or services. It must be called
         after the service is already associate with a node. For example, a service may need to authenticate with a
         server during installation, or create files in the node's filesystem.
-
-        :param node: Node on which this software runs.
-        :type node: Node
         """
-        parent: "Node" = self.parent  # noqa
+        pass
+
+    def uninstall(self) -> None:
+        """Uninstall this service from a node.
+
+        This is an abstract class that should be overwritten by applications or services. It must be called after the
+        `install` method has already been run on that node. It should undo any installation steps, for example by
+        deleting files, or contacting a server.
+        """
+        pass
 
     def scan(self) -> None:
         """Update the observed health status to match the actual health status."""

tests/integration_tests/system/test_database_on_node.py

@@ -20,3 +20,37 @@ def test_installing_database():
     node = Node(hostname="db-server")
 
     node.install_service(db)
+
+    assert db in node
+
+    file_exists = False
+    for folder in node.file_system.folders.values():
+        for file in folder.files.values():
+            if file.name == "db_primary_store":
+                file_exists = True
+                break
+        if file_exists:
+            break
+    assert file_exists
+
+
+def test_uninstalling_database():
+    db = DatabaseService(
+        name="SQL-database",
+        health_state_actual=SoftwareHealthState.GOOD,
+        health_state_visible=SoftwareHealthState.GOOD,
+        criticality=SoftwareCriticality.MEDIUM,
+        ports=[
+            Port.SQL_SERVER,
+        ],
+        operating_state=ServiceOperatingState.RUNNING,
+    )
+
+    node = Node(hostname="db-server")
+
+    node.install_service(db)
+
+    node.uninstall_service(db)
+
+    assert db not in node
+    assert node.file_system.get_folder_by_name("database") is None