simplify configuration of IO modules

As the communicator class needed for a module can be specified,
in the configuration we do not need to specifiy it explicitly.

A new configurator function IO() is introduced for this, defining
names and uri only.

- update also configuration reference and a tutorial example
- update get_class function to accept attributes of classes like
  'frappy_demo.lakshore.TemperatureSensor.ioClass' and import from
  modules other than frappy... like 'test.test_iocfg.Mod'.
- add ioClass to the example class for the temperature controller
  tutorial

Change-Id: I3115371d612f14024e43bc6d38b642e1d27b314d
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/38071
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

test/test_iocfg.py

@@ -0,0 +1,68 @@
+# *****************************************************************************
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# Module authors:
+#   Markus Zolliker <markus.zolliker@psi.ch>
+#
+# *****************************************************************************
+
+from logging import Logger
+import pytest
+from frappy.core import StringIO, Module, HasIO
+from frappy.config import process_file, fix_io_modules, Param
+
+
+class Mod(HasIO, Module):
+    ioClass = StringIO
+
+
+CONFIG = """
+IO('io_a', 'tcp://test.psi.ch:7777', visibility='w--')
+IO('io_b', 'tcp://test2.psi.ch:8080')
+
+Mod('mod1', 'test.test_iocfg.Mod', '',
+    io='io_a',
+    )
+
+Mod('mod2', 'test.test_iocfg.Mod', '',
+    io='io_b',
+    )
+
+Mod('mod3', 'test.test_iocfg.Mod', '',
+    io='io_b',
+    )
+"""
+
+
+@pytest.mark.parametrize('mod, ioname, iocfg', [
+    ('mod1', 'io_a', {
+        'cls': 'test.test_iocfg.Mod.ioClass',
+        'description': 'communicator for mod1',
+        'uri': Param('tcp://test.psi.ch:7777'),
+        'visibility': Param('w--')
+    },),
+    ('mod2', 'io_b', {
+        'cls': 'test.test_iocfg.Mod.ioClass',
+        'description': 'communicator for mod2, mod3',
+        'uri': Param('tcp://test2.psi.ch:8080'),
+    }),
+])
+def test_process_file(mod, ioname, iocfg):
+    log = Logger('dummy')
+    config = process_file('<test>',log, CONFIG)
+    fix_io_modules(config, log)
+    assert config[mod]['io'] == {'value': ioname}
+    assert config[ioname] == iocfg