Better error handling in case cluster is offline

ValveClusterServer.py

@@ -25,6 +25,8 @@ def isValidValveNumString(num):
 
 def errorNotAValidValveNumber(num):
     return '%s not a number or not in allowed range [1-24]' % num
+    
+clusterOfflineError = {'success': False, 'status': 'Valvecluster is offline'}
 
 #####
 #  Define routes
@@ -44,6 +46,8 @@ Get description of all valves
 @get('/description')
 def recipe_description():
     valveStates = getValveStates()
+    if valveStates is None:
+        return {'success': False, 'version': 1.1, 'name': 'Schrankenwaerter', 'status': 'Valvecluster is offline'}
     valveNums = range(1,len(valveStates)+1)
     
     valves = {
@@ -114,6 +118,9 @@ Get state of one or all control valves
 def recipe_controlValveState(num=None):
     valveStates = getControlValveStates()
     
+    if valveStates is None:
+        return clusterOfflineError
+    
     if num is None:
         return { 'success': True, 'state': dict(zip(range(1,len(valveStates)+1),valveStates)) }
         
@@ -133,6 +140,9 @@ of each valve
 def recipe_valveState(num=None):
     valveStates = getValveStates()
     
+    if valveStates is None:
+        return clusterOfflineError
+    
     if num is None:
         return { 'success': True, 'state': dict(zip(range(1,len(valveStates)+1),valveStates)) }
     if not isValidValveNumString(num):
@@ -166,19 +176,24 @@ def recipe_canOpenCloseValve(num,action):
 
 def send(command):
     url = 'http://10.0.0.31/http_in_ci?ci:%s' % command
-    
+    content = None
     try:
         content = urllib2.urlopen(url, timeout=0.2).read()
     except urllib2.URLError, e:
     # For Python 2.6
         if isinstance(e.reason, socket.timeout):
             print 'timeout',e
-        return None
+        else:
+            print 'urlerror:', e
+        #return None
     except httplib.BadStatusLine as e:
-        #print e.args
-        return None
+        print e
+        #return None
+    except:
+        import sys
+        print "Unexpected error:", sys.exc_info()[0] 
 
-    #print content
+    #print 'Content:', content
     return content
 
 def int2bitField(n):
@@ -276,11 +291,19 @@ def getControlValveStates():
         #    6 =    255 =  0  0  0  0  0  0  0  0  1  1  1  1  1  1  1  1
                             
                             
-        state = send('DAW%i'%unitNum)[1:] # Cluster returns sth like '=130' 
-                                          # -> chop of leading '='
+        state = send('DAW%i'%unitNum)
+        if state==None: # Cluster is offline!
+            return None
+        
+        state = state[1:] # Cluster returns sth like '=130' 
+                          # -> chop of leading '='
+                                          
         return int2bitField(int(state))[:8] # only first 8 bits are used
         
     states = [getControlValveState(unitNum) for unitNum in ausgangsWort]
+    for state in states:
+        if state is None:# Cluster is offline!
+            return None
     states = [item for sublist in states for item in sublist]
     states = states[:32:2]+states[32:]
     
@@ -307,11 +330,18 @@ def getValveStates():
         '''
         assert(unitNum in eingangsWort), \
                             'Unit number not in range of allowed eingangswörter'
-        state = send('DEW%i'%unitNum)[1:] # Cluster returns sth like '=130' 
-                                          # -> chop of leading '='
+        state = send('DEW%i'%unitNum)
+        if state==None: # Cluster is offline!
+            return None
+        state = state[1:] # Cluster returns sth like '=130' 
+                          # -> chop of leading '='
         return int2bitField(int(state))
         
     states = np.array([getUnitState(unitNum) for unitNum in eingangsWort])
+    
+    for state in states:
+        if state is None:# Cluster is offline!
+            return None
     states = states.reshape(-1,2)
     
     def stateListToNumber(state):

observer.html

@@ -61,8 +61,11 @@
             // Look for Schrankenwärter server. If found, adjust connect button and set up the valve list.
             function openConnectionToSchrankenwarter() {
                 // If connection is already open then close it (toggle open/close state)
-                if ($('#connectButton').button( "option", "label" )=='Connect') {
+                if ($('#connectButton').button( "option", "label" )=='Connect') { //Lousy definition of state...
                 	$('#statusTextField').text('Status: Connecting...')
+                    if ($('#buttoncontainer').is(':empty')){
+                      setupValveList();
+                    }
                     $.getJSON(inselAdresse+'description',
                         function(data) {
                             console.log(data)
@@ -78,6 +81,8 @@
                                 refreshIntervalId = setInterval(function() {
                                         updateValveStates()
                                     },200)
+                            } else {
+                                $('#statusTextField').text('Status: '+data.status)
                             }
                         }
                     ).error(function() { closeConnectionToSchrankenwarter(); })
@@ -102,7 +107,7 @@
             function setupValveList() {
                 $.getJSON(inselAdresse+'description',
                 function(data) {
-                    if (data.success!=true) {
+                    if (data.success==false) {
                     	$('#statusTextField').text('Error during communication with valve cluster');
                     	console.log('Communication error, response of valve cluster: ' + data);
                     } else {
@@ -155,6 +160,9 @@
                                 listItem.removeClass(classes).addClass('undef');
                             }
                         })
+                    } else {
+                        console.log('Error in updateValveStates, cluster seems to be offline');
+                        closeConnectionToSchrankenwarter()
                     }
                 }).error(function() {
                     console.log('Error in updateValveStates');