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SALOME Application Concept. Configuration for one or more computers
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*html version of this document is produced with docutils*::

  rst2html doc.txt > doc.html

This document corresponds to SALOME2 3.2.0

.. contents::
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| **WORK in PROGRESS, INCOMPLETE DOCUMENT** |
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The following explains how to configure your own application with your list of
modules, how to define and run this application on one or more computers.

General principles
------------------

A SALOME application is defined by a set of modules (GEOM, SMESH, ASTER...).

A SALOME User can define several SALOME Applications. These applications are
runnable from the same user account. These applications may share the same 
KERNEL and modules. Thus, the application configuration is independant of
KERNEL and must not be put in KERNEL_ROOT_DIR.

Furthermore, prerequisites may not be the same on all the applications.

A SALOME Session can run on a several computers.

Binary modules and prerequisites are installed on the different computers.
There is no need to have all the modules on each computer (the minimum is
KERNEL).

There is no need of standardization or centralised information on the details
of configuration on each computer (PATH, LD_LIBRARY_PATH, environment
variables) provided the application modules are version - compatible. Details
of configuration stay private to the computer, and are held by scripts on each
computer.

There is no hierarchy between the computers (for example only one master
computer used to launch application).

The SALOME user has an account on all the computers. Access between
account@computer is via rsh or ssh and must be configured for use without
password (key exchange for ssh). Account may be different on each
computer.

Application Directory
---------------------

Two ways for creation of an application directory
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

First way - references to different module directories
''''''''''''''''''''''''''''''''''''''''''''''''''''''

The script createAppli.sh in ${KERNEL_ROOT_DIR}/bin/salome creates an
application directory with the given path in parameter. ${APPLI} is a path 
relative to ${HOME}.

The directory is only a skeleton, the user has to edit several files to
configure his own application. These files are described after, the list is:

- env.d/atFirst.sh
- env.d/envProducts.sh
- env.d/envSalome.sh
- CatalogResources.xml
- SalomeApp.xml

Second and easiest way - one single virtual install directory
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

The user must create a SALOME application configuration file by modifying a
copy of ${KERNEL_ROOT_DIR}/bin/salome/config_appli.xml.
The file describes the list of SALOME modules used in the application, with
their respective installation path. The configuration file also defines the
path of an existing script which sets the SALOME prerequisites,
and optionnaly, the path of samples directory (SAMPLES_SRC).
The following command::

    python <KERNEL_ROOT_DIR>/bin/salome/appli_gen.py --prefix=<install directory> --config=<configuration file>

creates a virtual installation of SALOME in the application directory ${APPLI}
(bin, lib, doc, share...), with, for each file (executable, script, data,
library, resources...), symbolic links to the actual file.

Providing an existing an existing script for SALOME prerequisites (the same one
used for modules compilation, or given with the modules installation), the
installation works without further modification for a single computer (unless
some modules needs a special environment not defined in the above script).
For a distributed application (several computers), one must copy and adapt
CatalogResources.xml from ${KERNEL_ROOT_DIR}/bin/salome/appliskel (see below).

General rules
-------------

Directory ${APPLI} must be created on each computer of the application.
The easiest way is to use the same relative path (to ${HOME}) on each computer.
(Sometimes it is not possible to use the same path everywhere, for instance
when ${HOME} is shared with NFS, so it is possible to define different path
following the computers).

The ${APPLI} directory contains scripts for environment and runs. Environment
scripts must be configured (by the user) on each computer. All the environment
scripts are in the ${APPLI}/env.d directory. 

The script  ${APPLI}/envd sources **all** the files (\*.sh) in ${APPLI}/env.d
in alphanumeric order (after edition, think to remove backup files). the envd
script is used by run scripts.


env.d scripts
~~~~~~~~~~~~~
With the first way of installation, each user **must define** his own
configuration for these scripts, following the above rules.
With the virtual installation (second way, above), env.d
scripts are built automatically.

 **The following is only an example proposed by createAppli.sh, (first way of installation) not working as it is**.

atFirst.sh
    Sets the computer configuration not directly related to SALOME,
    like useful tools, default PATH.

envProducts.sh
    Sets the SALOME prerequisites.

envSALOME.sh
    Sets all the MODULE_ROOT_DIR that can be used in the SALOME application.

    SalomeAppConfig is also defined by::

      export SalomeAppConfig=${HOME}/${APPLI}

    where SalomeAppConfig designates the directory containing SalomeApp.xml. 
    Note that ${APPLI} is already defined by the calling scripts when 
    env.d/envSalome.sh is sourced.

User run scripts
~~~~~~~~~~~~~~~~

The SALOME user can use 4 scripts:

runAppli
   Launches a SALOME Session
   (similar to ${KERNEL_ROOT_DIR}/bin/salome/runSalome but with a different
   name to avoid confusions).

runSession
   Launches a shell script in the SALOME application environment, with access
   to the current (last launched) SALOME session (naming service), if any.
   Without arguments, the script is interactive. With arguments, the script
   executes the command in the SALOME application environment.

runConsole
   Gives a python console connected to the current SALOME Session.
   It is also possible to use runSession, then python.

runTests
   Similar to runSession, used for unit testing. runSession tries to use an
   already existing naming service definition from a running session (hostname
   and port number), runTests defines a new configuration for naming service
   (new port number).

SALOME internal run scripts
~~~~~~~~~~~~~~~~~~~~~~~~~~~

envd
   Sets SALOME application environment, envd is sourced by other scripts.

For remote calls, SALOME uses one script.

runRemote.sh
   This script is mainly used to launch containers. The first 2 arguments
   define the hostname and port userd for naming service, the remaining
   arguments define the command to execute.

Other configuration files
~~~~~~~~~~~~~~~~~~~~~~~~~

SalomeApp.xml
   This file is similar to the default given
   in ${GUI_ROOT_DIR}/share/salome/resources/gui


CatalogRessources.xml
   This files describes all the computers the application can use. The given
   example is minimal and suppose ${APPLI} is the same relative path
   to ${HOME}, on all the computers. A different directory can be set on a
   particular computer with a line::

       appliPath="my/specific/path/on/this/computer"


Examples of use
---------------

Launch a SALOME session with a GUI interface
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Launch is done with a command like::

   ./runAppli --logger

The --logger option means here : collect all the traces from the all the
distributed process, via CORBA, in a single file : logger.log.

There are a lot of options, a complete list is given by::

   ./runAppli --help

Note that, without argument, runAppli is a non interactive Python application,
and, with arguments, runAppli is an interactive Python interpreter.

Several options are already defined by default in SalomeApp.xml files. Optional
arguments given in the command override the SalomeApp.xml configuration.

Several sessions can run simultaneously, each session use a different port for
CORBA naming service, so the sessions are totally separated from each other.

When the GUI is closed, the different SALOME servers are still running.

Close a SALOME session, kill all the servers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Inside the interactive python interpreter you get when you use runAppli
with arguments, you can kill all the servers of your session with::

   >>> killLocalPort()

or the servers of all the sessions with::

   >>> killAllPorts()

If you have no active Python interpreter connected to your session, you can
kill all the SALOME servers of **all the sessions** on a given computer::

   ./runSession killSalome.py

Remember! it's the same idea in *Windows (R) operating system* [#]_ :
use the start menu to stop...

When you use only one session at a time, you don't need more.

To kill a given session (when several session are running), one needs
the naming service port number::

   ./runSession killSalomeWithPort 2810

Note that the port number of the last launched session can be found on Linux,
in the prompt, within a runSession shell (see below).

It is also possible to get the Naming Service host and port number of
the last launched session with::

   ./runSession NSparam.py

.. [#] Microsoft and Windows are either registered trademarks or trademarks of
       Microsoft Corporation in the United States and/or other countries.

Launch a SALOME session without GUI interface
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is used to launch a SALOME Python script without GUI
(no GUI server = SALOME_session_server)

Example of script (test_session_geom.py)::

   import salome_session
   salome_session.startSession(modules=["GEOM"])
   import GEOM_usinggeom
   raw_input("Press a key and the servers will be killed ...")

This script is run in a non interactive way with::

   ./runSession python test_session_geom.py

All the process are automatically killed when Python is closed
(with salome_session delete).

Add an external Python interpretor to a running session
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It's often easier to develop and try Python scripts outside the GUI embedded
Python interpreter. Imagine, for instance, you are writing a script involving
geometry and mesh modules.
first, launch a SALOME session with gui, then, on another terminal::

   ./runSession
   python

Import salome module. salome_init() without arguments creates a new study
in the running session (note: salome_init(n) attachs to a running session whose
studyId is n)::

   import salome
   salome.salome_init()

An example of script given with SMESH::

   import ex01_cube2build

It is possible to connect the GUI interface to the study created in the above
script with the file/connect menu, then browse study and display objects.
Further modifications on study can be done either with GUI or external script
(use refresh popup in GUI object browser to see study modifications generated
by the external script). **AVOID modifications with GUI when a Python script
is running**. Not all the modules are protected against concurrent actions...


Different uses of the runSession shell interpreter
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

runSession invoked without arguments gives an interactive shell with the full
environment of SALOME (PATH, LD_LIBRARY_PATH, PYTHONPATH, other variables).
If there are running sessions of the same SALOME application, runSession
connects to the last launched session (i.e. gets the naming service references
of the session: hostname and port)

On Linux, the shell prompt (bash) gives information on naming service
references, hostname and port::

   [NS=cli76cc:2811]prascle@cli76cc:~/SALOME2/Run/Virtual$

If there is no running session, prompt looks like::

   [NS=:]prascle@cli76cc:~/SALOME2/Run/Virtual$

runSession is useful to launch any script or program which needs the complete
SALOME environment, with or without a session already running.
For instance, to launch the ddd debugger interface on the gui server, first
launch a SALOME session with gui, then, on another terminal::

   ./runSession ddd

Then attach to the running SALOME_Session_Server process.


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+----------------------------------+------------------------------------------+
| `General KERNEL documentation`_  | `End User KERNEL Doxygen documentation`_ |
+----------------------------------+------------------------------------------+

.. _`General KERNEL documentation`:           ./index.html
.. _`End User KERNEL Doxygen documentation`:  ./tui/KERNEL/index.html
