add create system user

src/jupyterhub_config/custom_spawner.py

@@ -1,3 +1,8 @@
+import fcntl
+import os
+import subprocess
+import tempfile
+
 from jupyterhub.spawner import SimpleLocalProcessSpawner
 
 
@@ -14,4 +19,52 @@ def start(self):
         variables, and sets the notebook directory before starting the server.
         """
 
-        return super().start()
+        username = self.user.name
+
+        # Ensure the system user exists
+        self._ensure_system_user(username, group='jupyterhub')
+
+        return super().start()
+
+    def _ensure_system_user(self, username: str, group: str = None):
+        """
+        Create a system user with the given username if it does not already exist.
+        Ensure the group exists before creating the user.
+        Use a file lock to prevent race conditions.
+        """
+
+        lock_file = os.path.join(tempfile.gettempdir(), f'user_creation_{username}.lock')
+
+        with open(lock_file, 'w') as lock:
+            fcntl.flock(lock, fcntl.LOCK_EX)
+            try:
+                # Check if user already exists
+                result = subprocess.run(['id', username], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+                if result.returncode == 0:
+                    self.log.info(f'User {username} already exists')
+                    return
+
+                # Create the user
+                self.log.info(f'Creating system user: {username}')
+                useradd_cmd = ['sudo', 'useradd', '-r']
+
+                if group:
+                    # Check if the group exists, create if necessary
+                    group_check = subprocess.run(['getent', 'group', group], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+                    if group_check.returncode != 0:
+                        self.log.info(f'Group {group} does not exist, creating it.')
+                        subprocess.run(['sudo', 'groupadd', group], check=True)
+                    else:
+                        self.log.info(f'Group {group} already exists')
+
+                    useradd_cmd.extend(['-g', group])
+
+                useradd_cmd.append(username)
+
+                subprocess.run(useradd_cmd, check=True)
+
+            except subprocess.CalledProcessError as e:
+                raise ValueError(f'Failed to create system user: {e}')
+
+            finally:
+                fcntl.flock(lock, fcntl.LOCK_UN)

test/src/jupyterhub_config/custom_spawner_test.py

@@ -1 +1,101 @@
-from jupyterhub_config.custom_spawner import *
+import logging
+import subprocess
+import unittest
+from subprocess import CalledProcessError
+from unittest.mock import patch, MagicMock
+
+import pytest
+
+from jupyterhub_config.custom_spawner import VirtualEnvSpawner
+
+
+# Test when the user already exists
+@patch('subprocess.run')
+def test_ensure_system_user_already_exists(mock_run, caplog):
+    with caplog.at_level(logging.INFO):
+        # Mock 'id' command to simulate user already exists
+        mock_run.return_value.returncode = 0
+
+        spawner = VirtualEnvSpawner()
+        username = 'testuser'
+        spawner._ensure_system_user(username)
+
+        mock_run.assert_called_once_with(['id', username], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+        assert f'User {username} already exists' in caplog.text
+
+
+# Test when the group and user need to be created
+@patch('subprocess.run')
+def test_ensure_system_user_create_group_and_user(mock_run, caplog):
+    with caplog.at_level(logging.INFO):
+        # Define side_effect to simulate user does not exist, group does not exist, and then successful creation
+        mock_run.side_effect = [
+            MagicMock(returncode=1),  # 'id' command: User does not exist
+            MagicMock(returncode=2),  # 'getent' command: Group does not exist
+            MagicMock(returncode=0),  # 'groupadd' command: Group created successfully
+            MagicMock(returncode=0)  # 'useradd' command: User created successfully
+        ]
+
+        spawner = VirtualEnvSpawner()
+        username = 'testuser'
+        group = 'testgroup'
+        spawner._ensure_system_user(username, group)
+
+        expected_calls = [
+            unittest.mock.call(['id', username], stdout=subprocess.PIPE, stderr=subprocess.PIPE),
+            unittest.mock.call(['getent', 'group', group], stdout=subprocess.PIPE, stderr=subprocess.PIPE),
+            unittest.mock.call(['sudo', 'groupadd', group], check=True),
+            unittest.mock.call(['sudo', 'useradd', '-r', '-g', group, username], check=True)
+        ]
+
+        # Check that the expected calls were made in order
+        mock_run.assert_has_calls(expected_calls, any_order=False)
+
+        assert f'Creating system user: {username}' in caplog.text
+        assert f'Group {group} does not exist, creating it.' in caplog.text
+
+
+# Test when the user is created without a group
+@patch('subprocess.run')
+def test_ensure_system_user_create_user_without_group(mock_run, caplog):
+    with caplog.at_level(logging.INFO):
+        # Mock the 'id' command to simulate user does not exist
+        mock_run.side_effect = [
+            MagicMock(returncode=1),  # User does not exist
+            MagicMock(returncode=0)  # User created successfully
+        ]
+
+        spawner = VirtualEnvSpawner()
+        username = 'testuser'
+        spawner._ensure_system_user(username)
+
+        assert f'Creating system user: {username}' in caplog.text
+        expected_calls = [
+            unittest.mock.call(['id', username], stdout=subprocess.PIPE, stderr=subprocess.PIPE),
+            unittest.mock.call(['sudo', 'useradd', '-r', username], check=True)
+        ]
+
+        mock_run.assert_has_calls(expected_calls, any_order=False)
+
+
+# Test subprocess.CalledProcessError is handled correctly
+@patch('subprocess.run')
+def test_ensure_system_user_error(mock_run):
+    # Mock the 'id' command to simulate user does not exist
+    # Mock 'useradd' command to raise CalledProcessError
+    mock_run.side_effect = [
+        MagicMock(returncode=1),
+        CalledProcessError(1, 'useradd')
+    ]
+
+    spawner = VirtualEnvSpawner()
+    with pytest.raises(ValueError, match="Failed to create system user"):
+        spawner._ensure_system_user('testuser')
+
+    expected_calls = [
+        unittest.mock.call(['id', 'testuser'], stdout=subprocess.PIPE, stderr=subprocess.PIPE),
+        unittest.mock.call(['sudo', 'useradd', '-r', 'testuser'], check=True)
+    ]
+
+    mock_run.assert_has_calls(expected_calls, any_order=False)