Able to specify trend value (min, max or avg by default).

plugins/datasource-zabbix/datasource.js

@@ -132,12 +132,18 @@ function (angular, _, dateMath, utils, metricFunctions) {
               .then(function(items) {
                 // Add hostname for items from multiple hosts
                 var addHostName = target.host.isRegex;
-
                 var getHistory;
-                if ((from < useTrendsFrom) && self.trends) {
 
                 // Use trends
-                  var valueType = target.downsampleFunction ? target.downsampleFunction.value : "avg";
+                if ((from < useTrendsFrom) && self.trends) {
+
+                  // Find trendValue() function and get specified trend value
+                  var trendFunctions = _.map(metricFunctions.getCategories()['Trends'], 'name');
+                  var trendValueFunc = _.find(target.functions, function(func) {
+                    return _.contains(trendFunctions, func.def.name);
+                  });
+                  var valueType = trendValueFunc ? trendValueFunc.params[0] : "avg";
+
                   getHistory = self.zabbixAPI.getTrend(items, from, to).then(function(history) {
                     return self.queryProcessor.handleTrends(history, addHostName, valueType);
                   });

plugins/datasource-zabbix/metricFunctions.js

@@ -9,6 +9,7 @@ function (_, $) {
   var categories = {
     Transform: [],
     Aggregate: [],
+    Trends: [],
     Alias: []
   };
 
@@ -76,6 +77,15 @@ function (_, $) {
     defaultParams: ['1m'],
   });
 
+  addFuncDef({
+    name: 'trendValue',
+    category: 'Trends',
+    params: [
+      { name: 'type', type: 'string', options: ['avg', 'min', 'max'] }
+    ],
+    defaultParams: ['avg'],
+  });
+
   addFuncDef({
     name: 'setAlias',
     category: 'Alias',