nicolargo/glances · warning

Plugin {plugin} already in sys.modules, skipping (workaround

Error message

Plugin {plugin} already in sys.modules, skipping (workaround: rename plugin)

What it means

A logged warning (not a raised error) emitted while loading additional plugins from a configured directory: the plugin's module name already exists in sys.modules, so Glances skips importing it to avoid double-import side effects. The message suggests renaming the plugin as a workaround.

Source

Thrown at glances/stats.py:223

            path = args.plugin_dir

        # No additional plugin directory configured.
        if not path:
            return

        # Store original sys.path so it can be restored after loading.
        _sys_path = sys.path

        # Used to measure plugin startup duration.
        start_duration = Counter()

        # Ensure plugins can be imported from the configured directory.
        sys.path.insert(0, path)

        for plugin in self._get_addl_plugins(path):
            # Prevent duplicate imports for plugins already loaded.
            if plugin in sys.modules:
                logger.warn(f"Plugin {plugin} already in sys.modules, skipping (workaround: rename plugin)")
                continue

            start_duration.reset()
            try:
                # Dynamically import the plugin model module.
                _mod_loaded = import_module(plugin + '.model')

                # Create and register the plugin instance.
                self._plugins[plugin] = _mod_loaded.PluginModel(args=args, config=config)
                logger.debug(f"Plugin {plugin} started in {start_duration.get()} seconds")
            except Exception as e:
                # If a plugin can not be loaded, display a critical message
                # on the console but do not crash
                logger.critical(f"Error while initializing the {plugin} plugin ({e})")
                logger.error(traceback.format_exc())
                # An error occurred, disable the plugin
                if args:
                    setattr(args, 'disable_' + plugin, False)

View on GitHub (pinned to a240d8dfb3)

Solutions

1. Rename the custom plugin's module (directory/package name) to something unique, as the message suggests
2. Remove the duplicate copy if the built-in already covers it
3. Verify only one plugin path supplies each name; check sys.modules keys if unsure
4. Restart glances after renaming so the old module isn't already cached

Example fix

# before
# dir: glances_foo/ (collides with built-in 'glances_foo')
# after
mv glances_foo glances_foo_custom

import sys, pathlib
names = {p.name for p in pathlib.glob(plugin_dir)}
clashes = names & set(sys.modules)
if clashes:
    raise SystemExit(f'rename plugins to avoid collisions: {clashes}')

def plugin_name_free(name: str) -> bool:
    import sys
    return name not in sys.modules

When it happens

Trigger: Configuring additional plugin directories (--plugins-dir / plugin_path) that contain a plugin whose module name collides with a built-in or already-loaded one — e.g. a custom 'glances_plugin/foo' named the same as an existing plugin.

Common situations: Copying a stock plugin into a custom dir to modify it but keeping the module name; multiple plugin dirs containing same-named modules; iterating on plugins in the same interpreter/session.

Related errors

• Cannot get help view data ({str(e)})
• Cannot get plugin {plugin} ({str(e)})
• '{self.__class__.__name__}' object has no key '{item}'
• {item}
• Cannot get plugin list ({str(e)})

AI-assisted analysis of nicolargo/glances@a240d8dfb3 (2026-08-27). Data as JSON: /api/errors/5d603758e8e4a5e6. Report an issue: GitHub.