zoph: Fix cases when CLI user is set to "autodetect"

Closes: #2538

Tests:

- Without the patch, set the Zoph CLI User to "autodetect" and notice the
failure to load Zoph page.

- With the patch, set user to "autodetect" and access the app page. It is
updated to the first admin user in Zoph DB.

- Try with updating Zoph configuration.

- Try with re-running Zoph setup.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/db/mariadb.py

@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Utilities to help with MariaDB/MySQL databases.
+
+Uses utilities from 'mysql-client' package such as 'mysql' and 'mysqldump'.
+"""
+
+import subprocess
+
+
+def run_query(database_name: str, query: str) -> subprocess.CompletedProcess:
+    """Run a database query using 'root' user.
+
+    Does not ensure that the database server is running.
+    """
+    return subprocess.run(
+        ['mysql', '--user=root', '--database', database_name],
+        input=query.encode('utf-8'), check=True)

plinth/modules/zoph/privileged.py

@@ -9,6 +9,7 @@ import subprocess
 
 from plinth import action_utils
 from plinth.actions import privileged
+from plinth.db import mariadb
 
 APACHE_CONF = '/etc/apache2/conf-available/zoph.conf'
 DB_CONF = pathlib.Path('/etc/zoph.ini')
@@ -31,8 +32,17 @@ def pre_install():
 def get_configuration() -> dict[str, str]:
     """Return the current configuration."""
     configuration = {}
-    process = subprocess.run(['zoph', '--dump-config'], stdout=subprocess.PIPE,
-                             check=True)
+    try:
+        process = subprocess.run(['zoph', '--dump-config'],
+                                 stdout=subprocess.PIPE, check=True)
+    except subprocess.CalledProcessError as exception:
+        if exception.returncode != 96:
+            raise
+
+        _zoph_setup_cli_user()
+        process = subprocess.run(['zoph', '--dump-config'],
+                                 stdout=subprocess.PIPE, check=True)
+
     for line in process.stdout.decode().splitlines():
         name, value = line.partition(':')[::2]
         configuration[name.strip()] = value[1:]
@@ -40,9 +50,38 @@ def get_configuration() -> dict[str, str]:
     return configuration
 
 
+def _zoph_setup_cli_user() -> None:
+    """Ensure that Zoph cli user is not set to 'autodetect'.
+
+    When set to 'autodetect', all command line commands will fail unless a user
+    name 'root' exists in zoph database and is an admin user.
+    """
+    query = '''
+UPDATE
+  zoph_conf
+SET
+  value=(
+    SELECT user_id
+    FROM zoph_users
+    WHERE user_class="0"
+    ORDER BY user_id
+    LIMIT 1)
+WHERE
+  conf_id='interface.user.cli';'''
+    database_name = _get_db_config()['db_name']
+    mariadb.run_query(database_name, query)
+
+
 def _zoph_configure(key, value):
     """Set a configure value in Zoph."""
-    subprocess.run(['zoph', '--config', key, value], check=True)
+    try:
+        subprocess.run(['zoph', '--config', key, value], check=True)
+    except subprocess.CalledProcessError as exception:
+        if exception.returncode != 96:
+            raise
+
+        _zoph_setup_cli_user()
+        subprocess.run(['zoph', '--config', key, value], check=True)
 
 
 @privileged