###########################################
Environment Variables which control the LNM
###########################################

This page lists the environment variables that are read directly by the
``ln_manager``.

For message-definition lookup details, see :doc:`reference_mdefs`.


.. envvar:: LN_MESSAGE_DEFINITION_DIRS

Colon-separated list of additional message-definition root directories.

ln_manager includes these directories in its message-definition search path at
startup. The resulting search path is also exported to started processes as
part of the default process environment; see :ref:`process-environment`.

This variable is a global, user-environment based extension mechanism. For
instance-local configuration, prefer the
:ref:`add_message_definition_dir <global/add_message_definition_dir>` directive
in the ln-config file.


.. envvar:: LN_CONFIG

Path to the user-specific ln_manager config file.

Default is ``~/.ln_config``.

If the file exists, ln_manager executes it as Python code during startup and
uses it to override values from
``python/links_and_nodes_manager/config.py``; see :doc:`ln_manager_user_config`.

.. _lnm-ln-debug:

``LN_DEBUG``

Enable additional ln_manager debug behavior.

When set to a truthy value such as ``1`` or ``yes``, ln_manager enables extra
debug logging and some debug-only startup output.

For the client-side behavior of the same environment variable name, see
:envvar:`LN_DEBUG` in :doc:`ln_client_environment`.


.. envvar:: LN_ARBITER_PORT

Override the fixed TCP port that ln_manager uses to contact the per-host LN
daemon arbiter.

The built-in default is ``54376``.


.. envvar:: LN_BUILD_SUBDIR

Source-tree only override for the build directory name used by ln_manager when
it tries to locate build artifacts such as ``libln`` and ``ln_daemon``.

Default is ``build``.


.. envvar:: LN_SRC_TREE_DAEMON_START

Source-tree only override for the default command used to start ``ln_daemon``.

This affects the built-in default before any per-instance or per-host
``daemon_start_script`` config overrides are applied.


.. envvar:: LN_OPEN_SCOPE_ON_PARAMETER_DOUBLE_CLICK

Controls what happens when the user double-clicks a parameter row in the
parameters window.

Default is enabled.

When true, ln_manager requests publication of the parameter topic and opens a
scope on the parameter's ``.output`` field.


.. envvar:: LN_DAEMON_START

Override the built-in default daemon start command used by ln_manager; see
:ref:`hosts/daemon_start_script`.

This is intended as a site-local default. It is read during ln_manager startup
and used unless the ln-config overrides the daemon start script explicitly.


.. envvar:: LN_MANAGER_ASK_SHUTDOWN

defaults to ``yes``

if set to "yes" will ask the user whether to only close the gui and keep the
manager process alive when user wants to close the gui window while there are
still clients connected.
set this to ``no`` to disable this question and terminate ln_manager as soon as
users closes the gui window.


.. envvar:: LNM_TOPICS_DISPLAY_FLAT

Controls the initial topic display mode in the topics tree view.

By default ln_manager shows topics grouped as a tree by their dotted name
components.

Set this variable to ``1``, ``yes`` or ``true`` to disable that grouping and
start with a flat topic list instead.


.. envvar:: LN_MANAGER_CONDITIONS_CHECK_FOR_LONG_WAITERS

Internal debug toggle for ln_manager's ``Condition`` helper class.

Default is enabled.

When true, ln_manager starts a background checker thread that can detect and
report unusually long waits on these internal condition variables.


.. envvar:: LN_TERM_DEBUG

Enable debug logging for ln_manager's internal terminal/console input parser.


.. envvar:: LN_TERM_COLOR

Force colored terminal output handling in ln_manager's internal terminal code.

This is mainly a debug or compatibility knob for the terminal widget used to
show process output and console sessions.


.. envvar:: DEBUG_GETSTATE

Enable verbose debug prints while ln_manager serializes and restores internal
configuration objects via ``__getstate__`` / ``__setstate__`` style code paths.


.. envvar:: LN_CHECK_CB

Enable additional runtime validation of callback signatures in some internal
asynchronous helper wrappers.

This is a debugging aid for ln_manager development.


.. envvar:: LN_USE_OLD_PYSCOPE

Instead of using new ``links_and_nodes.scope`` for plotting signals when double clicking on fields
in the PortInspector, use the old OpenGL-based pyscope.

###################################################
Standard environment variables read by the LNM code
###################################################

These are not LN-specific, but ln_manager does read them directly.


.. envvar:: DISPLAY

Used by the GUI and X11 forwarding code.

ln_manager reports the GUI display to connected sessions, uses it to resolve
X11 forwarding targets and cookies, and also includes the display value in the
per-display filename used to remember window geometry.


.. envvar:: XAUTHORITY

Used to locate the X11 authority database.

If unset, ln_manager falls back to ``$HOME/.Xauthority``; see
:doc:`x11_connections`.


.. envvar:: HOME

Used for several path defaults, including ``~/.ln_config``,
``~/ln_message_definitions/gen``, and the fallback path for
``XAUTHORITY``. It is also propagated in some process-start/X11-forwarding
cases.


.. envvar:: HOSTNAME

Used only as a last-resort fallback when ln_manager tries to determine the
local host name for built-in config variables.


.. envvar:: EDITOR

Used as the preferred external editor command in the processes GUI.

Default is ``/usr/bin/gedit``.


#################################################
Environment Variables which control the LN daemon
#################################################

.. envvar:: LN_DAEMON_NO_HIDE

default ``no``

if set to ``yes`` will show each and every received request from the ln_manager
connection.