stateengine plugin: improve graphviz issue handling and logging

stateengine/StateEngineWebif.py

@@ -357,8 +357,12 @@ def drawgraph(self, filename):
                 self.__conditionset_count = len(self.__states[state].get('conditionsets'))
                 if self.__conditionset_count == 0:
                     self.__states[state]['conditionsets'][''] = ''
+                try:
+                    list_index = list(self.__states.keys()).index(self.__active_state)
+                except Exception:
+                    list_index = 0
                 color = "chartreuse3" if state == self.__active_state \
-                    else "gray" if i > list(self.__states.keys()).index(self.__active_state) else "indianred2"
+                    else "gray" if i > list_index else "indianred2"
 
                 new_y -= 1 * self.__scalefactor
                 position = '{},{}!'.format(0, new_y)

stateengine/__init__.py

@@ -35,6 +35,13 @@
 from lib.item import Items
 from .webif import WebInterface
 
+try:
+    import pydotplus
+    VIS_ENABLED = True
+except Exception:
+    VIS_ENABLED = False
+
+
 logging.addLevelName(StateEngineDefaults.VERBOSE, 'DEVELOP')
 
 
@@ -52,6 +59,9 @@ def __init__(self, sh):
         self.__sh = sh
         self.alive = False
         self.__cli = None
+        self.vis_enabled = self._test_visualization()
+        if not self.vis_enabled:
+            self.logger.warning(f'StateEngine is missing the PyDotPlus package, WebIf visualization is disabled')
         self.init_webinterface(WebInterface)
         self.__log_directory = self.get_parameter_value("log_directory")
         try:
@@ -206,9 +216,9 @@ def get_graph(self, abitem, graphtype='link'):
                         <img src="static/img/visualisations/{0}.svg"\
                         style="max-width: 100%; height: auto; width: auto\9; ">\
                         </iframe></object>'.format(abitem)
-        except ImportError as ex:
-           self.logger.error("Problem getting graph for {}. ImportError: {}".format(abitem, ex))
-           return '<h4>Can not show visualization.</h4> ' \
+        except pydotplus.graphviz.InvocationException as ex:
+           self.logger.error("Problem getting graph for {}. Error: {}".format(abitem, ex))
+           return '<h4>Can not show visualization. Most likely GraphViz is not installed.</h4> ' \
                   'Current issue: ' + str(ex) + '<br/>'\
                   'Please make sure <a href="https://graphviz.org/download/" target="_new">' \
                   'graphviz</a> is installed.<br/>' \
@@ -217,4 +227,23 @@ def get_graph(self, abitem, graphtype='link'):
         except Exception as ex:
             self.logger.error("Problem getting graph for {}. Unspecified Error: {}".format(abitem, ex))
             return '<h4>Can not show visualization.</h4> ' \
-                   'Current unspecified issue: ' + str(ex) + '<br/>'
+                   'Current issue: ' + str(ex) + '<br/>'
+
+
+    def _test_visualization(self):
+        if not VIS_ENABLED:
+            return False
+
+        img_path = self.path_join(self.get_plugin_dir(), 'webif/static/img/visualisations/se_test')
+        graph = pydotplus.Dot('StateEngine', graph_type='digraph', splines='false',
+                                     overlap='scale', compound='false', imagepath=img_path)
+        graph.set_node_defaults(color='lightgray', style='filled', shape='box',
+                                       fontname='Helvetica', fontsize='10')
+        graph.set_edge_defaults(color='darkgray', style='filled', shape='box',
+                                       fontname='Helvetica', fontsize='10')
+
+        try:
+            result = graph.write_svg(img_path, prog='fdp')
+        except pydotplus.graphviz.InvocationException:
+            return False
+        return True

stateengine/locale.yaml

@@ -13,3 +13,4 @@ plugin_translations:
     'Items':                                                        {'de': '=', 'en': '='}
     'SE Item':                                                      {'de': '=', 'en': '='}
     'Detailvisualisierung':                                         {'de': '=', 'en': 'Detailed Visualization'}
+    'KeineVisualisierung':                                          {'de': 'Visualisierung nicht verfügbar', 'en': 'Visualization not available'}

stateengine/webif/templates/index.html

@@ -107,7 +107,9 @@
 <div class="container-fluid m-2 table-resize">
   <div class="mb-2">
     {{ _('Die folgenden Items verfügen über ein StateEngine Item') }}.
-    <strong>{{ _('Klick auf das Lupensymbol öffnet die Visualisierung!') }}</strong>
+    {% if p.vis_enabled %}
+      <strong>{{ _('Klick auf das Lupensymbol öffnet die Visualisierung!') }}</strong>
+    {% endif %}
   </div>
   <table id="maintable">
     <thead>
@@ -128,7 +130,12 @@
         <td class="py-1" id="{{ item }}_lastconditionset">
           {% if item.lastconditionset_name == "" %}-{% else %}{{ item.lastconditionset_name }}{% endif %}</td>
         <td>
-          <button type="button" class="btn btn-shng btn-sm" title="{{ _('Detailvisualisierung') }}" onclick="location.href='?action=get_graph&abitem={{ item }}';"><i class="fas fa-search"></i></button></td>
+          {% if p.vis_enabled %}
+            <button type="button" class="btn btn-shng btn-sm" title="{{ _('Detailvisualisierung') }}" onclick="location.href='?action=get_graph&abitem={{ item }}';"><i class="fas fa-search"></i></button>
+          {% else %}
+            <span title="{{ _('KeineVisualisierung') }}">X</span>
+          {% endif %}
+        </td>
         <td class="py-1">{{ item.log_level }}</td>
         <td class="py-1">{% for cond in item.webif_infos.keys() %}{% if not p.itemsApi.return_item(cond) == None %}{% if loop.index > 1 %},{% endif %}{{ p.itemsApi.return_item(cond)._name.split('.')[-1] }}{% endif %}{% endfor %}</td>