fix(guest_override-cache): move guest override from cache to db and c…

…ollect some sql related calls inside models.py's classes

guest override flag is now managed with models.get_flag and models.set_flag instead of using the state cache
state cache is not reliable when multiple containers serve the app simultaneously (every container has a different panel.state.cache object
add the optional parameter value_if_missing to models.get_flag to set a default value instead of returning None
add a clean method and a read_as_df method to every table object (see models.py) to improve code readability
add a clear_guest_override method to the class models.Flags to clean app every guest_override flag (those are saved on a per-user basis)
add InvalidToken error handling in auth (this only happen if DATA_LUNCH_OAUTH_ENC_KEY changes but the guest user password is not updated for basic auth
rename 'cache' to 'flags' in variables and properties for gui.py

data_lunch_app/__init__.py

@@ -42,10 +42,17 @@ def create_app(config: DictConfig) -> pn.Template:
     # Set the no_more_orders flag if it is None (not found in flags table)
     if models.get_flag(config=config, id="no_more_orders") is None:
         models.set_flag(config=config, id="no_more_orders", value=False)
-    # Set guest override if it is empty
-    guest_override = pn.state.cache.get(
-        f"{pn.state.user}_guest_override", False
-    )
+    # Set guest override flag if it is None (not found in flags table)
+    # Guest override flag is per-user and is not set for guests
+    if (
+        models.get_flag(config=config, id=f"{pn.state.user}_guest_override")
+        is None
+    ) and not auth.is_guest(
+        user=pn.state.user, config=config, allow_override=False
+    ):
+        models.set_flag(
+            config=config, id=f"{pn.state.user}_guest_override", value=False
+        )
 
     # DASHBOARD BASE TEMPLATE
     log.debug("instantiate base template")
@@ -95,7 +102,11 @@ def create_app(config: DictConfig) -> pn.Template:
         reload=False,
     )
     gi.reload_on_guest_override(
-        toggle=guest_override,
+        toggle=models.get_flag(
+            config=config,
+            id=f"{pn.state.user}_guest_override",
+            value_if_missing=False,
+        ),
         reload=False,
     )
     core.reload_menu(

data_lunch_app/auth.py

@@ -433,20 +433,14 @@ def list_users_guests_and_privileges(config: DictConfig) -> pd.DataFrame:
     """Join privileged users' table and credentials tables to list users,
     admins and guests.
     Returns a dataframe."""
-    # Create session
-    engine = models.create_engine(config)
 
     # Query tables required to understand users and guests
-    df_privileged_users = pd.read_sql_table(
-        models.PrivilegedUsers.__tablename__,
-        engine,
-        schema=config.db.get("schema", None),
+    df_privileged_users = models.PrivilegedUsers.read_as_df(
+        config=config,
         index_col="user",
     )
-    df_credentials = pd.read_sql_table(
-        models.Credentials.__tablename__,
-        engine,
-        schema=config.db.get("schema", None),
+    df_credentials = models.Credentials.read_as_df(
+        config=config,
         index_col="user",
     )
     # Change admin column to privileges (used after join)
@@ -468,10 +462,12 @@ def is_guest(
     The guest override chached value (per-user) can force the function to always return True.
     If allow_override is set to False the guest override value is ignored."""
 
-    # Load guest override from state cache (if the button is pressed its value
+    # Load guest override from flag table (if the button is pressed its value
     # is True). If not available use False.
-    guest_override = pn.state.cache.get(
-        f"{pn.state.user}_guest_override", False
+    guest_override = models.get_flag(
+        config=config,
+        id=f"{pn.state.user}_guest_override",
+        value_if_missing=False,
     )
 
     # If guest override is active always return true (user act like guest)

data_lunch_app/core.py

@@ -22,6 +22,7 @@
 
 # Authentication
 from . import auth
+import cryptography.fernet
 
 # LOGGER ----------------------------------------------------------------------
 log = logging.getLogger(__name__)
@@ -67,26 +68,20 @@ def delete_files(config: DictConfig):
 
 def clean_tables(config: DictConfig):
     # Clean tables
-    session = models.create_session(config)
-    with session:
-        # Clean orders
-        num_rows_deleted = session.execute(delete(models.Orders))
-        session.commit()
-        log.info(f"deleted {num_rows_deleted.rowcount} from table 'orders'")
-        # Clean menu
-        num_rows_deleted = session.execute(delete(models.Menu))
-        session.commit()
-        log.info(f"deleted {num_rows_deleted.rowcount} from table 'menu'")
-        # Clean users
-        num_rows_deleted = session.execute(delete(models.Users))
-        session.commit()
-        log.info(f"deleted {num_rows_deleted.rowcount} from table 'users'")
-        # Clean flags
-        models.set_flag(config=config, id="no_more_orders", value=False)
-        log.info("reset values in table 'flags'")
-        # Clean cache
-        pn.state.clear_caches()
-        log.info("cache cleaned")
+    # Clean orders
+    models.Orders.clear(config=config)
+    # Clean menu
+    models.Menu.clear(config=config)
+    # Clean users
+    models.Users.clear(config=config)
+    # Clean flags
+    models.Flags.clear_guest_override(config=config)
+    # Reset flags
+    models.set_flag(config=config, id="no_more_orders", value=False)
+    log.info("reset values in table 'flags'")
+    # Clean cache
+    pn.state.clear_caches()
+    log.info("cache cleaned")
 
 
 def set_guest_user_password(config: DictConfig) -> str:
@@ -130,9 +125,20 @@ def set_guest_user_password(config: DictConfig) -> str:
             # Load from database
             session = models.create_session(config)
             with session:
-                guest_password = session.get(
-                    models.Credentials, "guest"
-                ).password_encrypted.decrypt()
+                try:
+                    guest_password = session.get(
+                        models.Credentials, "guest"
+                    ).password_encrypted.decrypt()
+                except cryptography.fernet.InvalidToken:
+                    # Notify exception and suggest to reset guest user password
+                    guest_password = ""
+                    log.warning(
+                        "Unable to decrypt 'guest' user password because an invalid token has been detected: reset password from backend"
+                    )
+                    pn.state.notifications.warning(
+                        "Unable to decrypt 'guest' user password<br>Invalid token detected: reset password from backend",
+                        duration=config.panel.notifications.duration,
+                    )
     else:
         guest_password = ""
 
@@ -290,9 +296,11 @@ def reload_menu(
 
             return
 
-        # Check guest override button status
-        gi.toggle_guest_override_button.value = pn.state.cache.get(
-            f"{pn.state.user}_guest_override", False
+        # Check guest override button status (if not in table use False)
+        gi.toggle_guest_override_button.value = models.get_flag(
+            config=config,
+            id=f"{pn.state.user}_guest_override",
+            value_if_missing=False,
         )
 
         # Guest graphic configuration
@@ -307,10 +315,8 @@ def reload_menu(
 
         # Reload menu
         engine = models.create_engine(config)
-        df = pd.read_sql_table(
-            models.Menu.__tablename__,
-            engine,
-            schema=config.db.get("schema", models.SCHEMA),
+        df = models.Menu.read_as_df(
+            config=config,
             index_col="id",
         )
         df["order"] = False
@@ -772,10 +778,8 @@ def df_list_by_lunch_time(
     # Create database engine and session
     engine = models.create_engine(config)
     # Read menu and save how menu items are sorted (first courses, second courses, etc.)
-    original_order = pd.read_sql_table(
-        models.Menu.__tablename__,
-        engine,
-        schema=config.db.get("schema", models.SCHEMA),
+    original_order = models.Menu.read_as_df(
+        config=config,
         index_col="id",
     ).item
     # Create session

data_lunch_app/gui.py

@@ -227,12 +227,16 @@ def reload_on_guest_override_callback(
             toggle: pnw.ToggleIcon, reload: bool = True
         ):
             # Update global variable that control guest override
-            # Only non guest can store this value in cache (guest users are
-            # always guests)
+            # Only non guest can store this value in 'flags' table (guest users
+            # are always guests, there is no use in sotring a flag for them)
             if not auth.is_guest(
                 user=pn.state.user, config=config, allow_override=False
             ):
-                pn.state.cache[f"{pn.state.user}_guest_override"] = toggle
+                models.set_flag(
+                    config=config,
+                    id=f"{pn.state.user}_guest_override",
+                    value=toggle,
+                )
             # Show banner if override is active
             self.guest_override_alert.visible = toggle
             # Simply reload the menu when the toggle button value changes
@@ -905,13 +909,12 @@ def __init__(
         self.users_tabulator = pn.widgets.Tabulator(
             value=auth.list_users_guests_and_privileges(config),
         )
-        # Cache content
-        self.cache_content = pn.widgets.JSONEditor(
-            value=pn.state.cache,
-            name="Cache Content",
-            mode="view",
-            sizing_mode="stretch_both",
+        # Flags content (use empty dataframe to instantiate)
+        df_flags = models.Flags.read_as_df(
+            config=config,
+            index_col="id",
         )
+        self.flags_content = pn.widgets.Tabulator(value=df_flags)
 
         # BUTTONS
         # Exit button
@@ -942,9 +945,9 @@ def __init__(
             icon_size="2em",
             sizing_mode="stretch_width",
         )
-        # Clear cache button
-        self.clear_cache_button = pnw.Button(
-            name="Clear Server Cache",
+        # Clear flags table button
+        self.clear_flags_button = pnw.Button(
+            name="Clear Guest Override Flags",
             button_type="danger",
             height=generic_button_height,
             icon="file-shredder",
@@ -976,11 +979,11 @@ def __init__(
             self.delete_user_button,
             width=sidebar_width,
         )
-        self.clear_cache_column = pn.Column(
-            pn.pane.HTML("<b>Cache Content</b>"),
-            self.cache_content,
+        self.clear_flags_column = pn.Column(
+            pn.pane.HTML("<b>Flags Table Content</b>"),
+            self.flags_content,
             pn.VSpacer(),
-            self.clear_cache_button,
+            self.clear_flags_button,
             width=sidebar_width,
         )
         # Create for deleting users
@@ -1022,7 +1025,7 @@ def __init__(
                     sizing_mode="stretch_height",
                 )
             )
-            self.backend_controls.append(self.clear_cache_column)
+            self.backend_controls.append(self.clear_flags_column)
             self.backend_controls.append(
                 pn.pane.HTML(
                     styles=dict(background="lightgray"),
@@ -1089,27 +1092,34 @@ def delete_user_button_callback(self):
             lambda e: delete_user_button_callback(self)
         )
 
-        # Clear cache callback
-        def clear_cache_button_callback(self):
-            pn.state.clear_caches()
-            pn.state.cache = {}
+        # Clear flags callback
+        def clear_flags_button_callback(self):
+            # Clear flags
+            num_rows_deleted = models.Flags.clear_guest_override(config=config)
+            # Reload and notify user
             self.reload_backend(config)
             pn.state.notifications.success(
-                "Cache cleared",
+                f"Guest override flags cleared<br>{num_rows_deleted} rows deleted",
                 duration=config.panel.notifications.duration,
             )
 
-        self.clear_cache_button.on_click(
-            lambda e: clear_cache_button_callback(self)
+        self.clear_flags_button.on_click(
+            lambda e: clear_flags_button_callback(self)
         )
 
     # UTILITY FUNCTIONS
     # MAIN SECTION
     def reload_backend(self, config) -> None:
+        # Users and guests lists
         self.users_tabulator.value = auth.list_users_guests_and_privileges(
             config
         )
-        self.cache_content.value = pn.state.cache
+        # Flags table content
+        df_flags = models.Flags.read_as_df(
+            config=config,
+            index_col="id",
+        )
+        self.flags_content.value = df_flags
 
     def exit_backend(self) -> None:
         # Edit pathname to force exit