Analytics: sink units

- Allowing users to define analyzers with inputs but no outputs
- In this case, a "sink" unit is created, which always refers to the
root of the sensor tree
- This is useful for control analyzers that tune system knobs but do
not actively produce sensor data

analytics/analyzers/aggregator/JobAggregatorConfigurator.cpp

@@ -67,4 +67,10 @@ void JobAggregatorConfigurator::analyzer(JobAggregatorAnalyzer& a, CFG_VAL confi
     }
 }
 
-bool JobAggregatorConfigurator::unit(UnitTemplate<AggregatorSensorBase>& u) { return true; }
\ No newline at end of file
+bool JobAggregatorConfigurator::unit(UnitTemplate<AggregatorSensorBase>& u) {
+    if(u.getOutputs().empty()) {
+        LOG(error) << _analyzerName << ": At least one output sensor per unit must be defined!";
+        return false;
+    }
+    return true; 
+}
\ No newline at end of file

analytics/includes/AnalyzerConfiguratorTemplate.h

@@ -509,6 +509,9 @@ protected:
      */
     virtual bool readUnits(Analyzer& an, std::vector<shared_ptr<SBase>>& protoInputs, std::vector<shared_ptr<SBase>>& protoOutputs, inputMode_t inputMode) {
         vector <shared_ptr<UnitTemplate<SBase>>> *units = NULL;
+        if(protoOutputs.empty())
+            LOG(debug) << "    No output specified, generating sink unit.";
+        
         try {
             units = _unitGen.generateUnits(protoInputs, protoOutputs, inputMode, an.getMqttPart(), !an.getStreaming(), an.getRelaxed());
         }

analytics/includes/UnitGenerator.h

@@ -183,17 +183,17 @@ public:
     vector<shared_ptr<UnitTemplate<SBase>>> *generateUnits(vector<shared_ptr<SBase>>& inputs, vector<shared_ptr<SBase>>& outputs, 
             inputMode_t inputMode, string mqttPrefix="", bool ondemand=false, bool relaxed=false) {
         
-        // If no outputs are defined, no units can be instantiated
-        if((inputs.empty() && inputMode==SELECTIVE) || outputs.empty())
-            throw invalid_argument("UnitGenerator: Invalid inputs or outputs!");
+        // If no inputs are defined, no units can be instantiated
+        if(inputs.empty() && inputMode==SELECTIVE)
+            throw invalid_argument("UnitGenerator: Invalid inputs!");
 
         // Output sensors must share the same unit pattern
-        if(!isConsistent(outputs))
+        if(!outputs.empty() && !isConsistent(outputs))
             throw invalid_argument("UnitGenerator: Incoherent output levels!");
 
         // We iterate over the outputs, and compute their depth level in the current sensor tree. From such depth level,
         // the list of units is defined, consisting in all nodes in the sensor tree at the level of the outputs
-        int unitLevel = parseNodeLevelString(outputs[0]->getName());
+        int unitLevel = outputs.empty() ? -1 : parseNodeLevelString(outputs[0]->getName());
         set<string>* units = NULL;
         if(unitLevel > -1)
             units = resolveNodeLevelString(outputs[0]->getName(), SensorNavigator::rootKey, false);
@@ -250,16 +250,16 @@ public:
     shared_ptr<UnitTemplate<SBase>> generateUnit(const string& u, vector<shared_ptr<SBase>>& inputs, vector<shared_ptr<SBase>>& outputs,
             inputMode_t inputMode, string mqttPrefix="", bool relaxed=false) {
         
-        // If no outputs are defined, no units can be instantiated
-        if((inputs.size()==0 && inputMode==SELECTIVE) || outputs.size() == 0)
-            throw invalid_argument("UnitGenerator: Invalid inputs or outputs!");
+        // If no inputs are defined, no units can be instantiated
+        if(inputs.size()==0 && inputMode==SELECTIVE)
+            throw invalid_argument("UnitGenerator: Invalid inputs!");
 
         // Output sensors must share the same unit pattern
-        if(!isConsistent(outputs))
+        if(!outputs.empty() && !isConsistent(outputs))
             throw invalid_argument("UnitGenerator: Incoherent output levels!");
 
         // The unit specified as input must belong to the domain of the outputs
-        if(!nodeBelongsToPattern(u, outputs[0]->getName()))
+        if(!nodeBelongsToPattern(u, outputs.empty() ? SensorNavigator::rootKey : outputs[0]->getName()))
             throw domain_error("UnitGenerator: Node " + u + " does not belong to this unit domain!");
 
         return _generateUnit(u, inputs, outputs, inputMode, mqttPrefix, relaxed);
@@ -288,7 +288,7 @@ public:
             vector<shared_ptr<SBase>>& outputs, vector<shared_ptr<SBase>>& subInputs, vector<shared_ptr<SBase>>& subOutputs,
             inputMode_t inputMode, string mqttPrefix="", bool relaxed=false) {
 
-        // If no outputs are defined, no units can be instantiated
+        // If no inputs or outputs are defined, no units can be instantiated
         if((subInputs.size()==0 && inputMode==SELECTIVE) || subOutputs.size()==0)
             throw invalid_argument("HiUnitGenerator: Invalid inputs or outputs!");