From 8501f32d8f67fd53bbc682ba9bfadd0ce5f39345 Mon Sep 17 00:00:00 2001
From: Richard Wall <richard@largo>
Date: Mon, 8 Aug 2011 00:52:07 +0100
Subject: Add a transformer option to allow operations on the data from RRD
 files - eg Network octets * 8 > bits

---
 docs/examples/jarmon_example_recipes.js |  4 ++--
 jarmon/jarmon.js                        | 26 +++++++++++++++++++++-----
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/docs/examples/jarmon_example_recipes.js b/docs/examples/jarmon_example_recipes.js
index a2e822e..aa42d6f 100644
--- a/docs/examples/jarmon_example_recipes.js
+++ b/docs/examples/jarmon_example_recipes.js
@@ -54,8 +54,8 @@ jarmon.CHART_RECIPES_COLLECTD = {
     'interface': {
         title: 'Wlan0 Throughput',
         data: [
-            ['data/interface/if_octets-wlan0.rrd', 'tx', 'Transmit', 'B/s'],
-            ['data/interface/if_octets-wlan0.rrd', 'rx', 'Receive', 'B/s']
+            ['data/interface/if_octets-wlan0.rrd', 'tx', 'Transmit', 'bit/s', function (v) { return v*8; }],
+            ['data/interface/if_octets-wlan0.rrd', 'rx', 'Receive', 'bit/s', function (v) { return v*8; }]
         ],
         options: jQuery.extend(true, {}, jarmon.Chart.BASE_OPTIONS)
     }
diff --git a/jarmon/jarmon.js b/jarmon/jarmon.js
index 65ebedc..f6c3948 100644
--- a/jarmon/jarmon.js
+++ b/jarmon/jarmon.js
@@ -337,10 +337,17 @@ jarmon.localTimeFormatter = function (v, axis) {
  * @constructor
  * @param rrd {Object} A javascriptrrd.RRDFile
  * @param unit {String} The unit symbol for this data series
+ * @param transformer {Function} A callable which performs a
+ *      tranfsformation of the values returned from the RRD file.
  **/
-jarmon.RrdQuery = function(rrd, unit) {
+jarmon.RrdQuery = function(rrd, unit, transformer) {
     this.rrd = rrd;
     this.unit = unit;
+    if(typeof(transformer) !== 'undefined') {
+ 	    this.transformer = transformer;
+ 	} else {
+ 	    this.transformer = function(v) {return v;};
+ 	}
 };
 
 jarmon.RrdQuery.prototype.getData = function(startTimeJs, endTimeJs,
@@ -443,7 +450,7 @@ jarmon.RrdQuery.prototype.getData = function(startTimeJs, endTimeJs,
     var val;
     var timestamp = startRowTime;
     for(i=startRowIndex; i<endRowIndex; i++) {
-        val = rra.getEl(i, dsIndex);
+        val = this.transformer(rra.getEl(i, dsIndex));
         flotData.push([timestamp*1000.0, val]);
         timestamp += step;
     }
@@ -480,11 +487,19 @@ jarmon.RrdQuery.prototype.getDSNames = function() {
  * @param unit {String} The unit suffix of this data eg 'bit/sec'
  * @param downloader {Function} A callable which returns a Deferred and calls
  *      back with a javascriptrrd.BinaryFile when it has downloaded.
+ * @param transformer {Function} A callable which performs a
+ *      tranfsformation of the values returned from the RRD file.
  **/
-jarmon.RrdQueryRemote = function(url, unit, downloader) {
+jarmon.RrdQueryRemote = function(url, unit, downloader, transformer) {
     this.url = url;
     this.unit = unit;
-    this.downloader = downloader || jarmon.downloadBinary;
+    if(typeof(downloader) == 'undefined') {
+        this.downloader = jarmon.downloadBinary;
+    } else {
+        this.downloader = downloader;
+    }
+    this.transformer = transformer;
+
     this.lastUpdate = 0;
     this._download = null;
 };
@@ -693,10 +708,11 @@ jarmon.Chart.prototype.setup = function() {
         }
         var label = recipe.data[j][2];
         var unit = recipe.data[j][3];
+        var transformer = recipe.data[j][4];
 
         if(typeof(dataDict[rrd]) === 'undefined') {
             dataDict[rrd] = new jarmon.RrdQueryRemote(
-                rrd, unit, this.downloader);
+                rrd, unit, this.downloader, transformer);
         }
         this.addData(label, new jarmon.RrdQueryDsProxy(dataDict[rrd], ds));
     }
-- 
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