Add sum aggregator

README.md

@@ -53,6 +53,7 @@ Available aggregators:
 
 * `min`, `max`, `mean`: Computes the min, max, mean of the field's values during the sample interval.
 * `median`, `p#`: The p1 to p99 compute the percentile of the field's values during the sample interval.
+* `sum`: Sum all values for the field.
 * `[bucket1,bucketN]hist`: Count number of values between bucket and bucket+1.
 * `[bucket1,bucketN]cat`: Count number of values equal to the define buckets (can be non-number values). The special `*` matches values that fit in none of the defined buckets.
 
@@ -64,16 +65,15 @@ Jaggr can be used to integrate [vegeta](https://github.com/tsenart/vegeta) with
 
 ```
 echo 'GET http://localhost:8080' | \
-    vegeta attack -rate 5000 -workers 100 -duration 10m | vegeta dump | \
+    vegeta attack -rate 5000 -duration 10m | vegeta dump | \
     jaggr @count=rps \
-          hist[100,200,300,400,500]:code \
+          hist\[100,200,300,400,500\]:code \
           p25,p50,p95:latency \
-          p25,p50,p95:bytes_in \
-          p25,p50,p95:bytes_out | \
+          sum:bytes_in \
+          sum:bytes_out | \
     jplot rps+code.hist.100+code.hist.200+code.hist.300+code.hist.400+code.hist.500 \
           latency.p95+latency.p50+latency.p25 \
-          bytes_in.p95+bytes_in.p50+bytes_in.p25 \
-          bytes_out.p95+bytes_out.p50+bytes_out.p25
+          bytes_in.sum+bytes_out.sum
 ```
 
 ![](doc/vegeta.gif)

aggr/aggr.go

@@ -13,6 +13,7 @@ func init() {
 	Register("max", newMax)
 	Register("mean", newMean)
 	Register("median", newMedian)
+	Register("sum", newSum)
 	Register("hist", newHist)
 	Register("cat", newCat)
 	for i := 1; i < 100; i++ {

aggr/sum.go

@@ -0,0 +1,24 @@
+package aggr
+
+type sum struct {
+	v float64
+}
+
+func newSum(args []string) (Aggregator, error) {
+	return &sum{}, nil
+}
+
+func (a *sum) Push(v interface{}) error {
+	f, err := parseFloat(v)
+	if err != nil {
+		return err
+	}
+	a.v += f
+	return nil
+}
+
+func (a *sum) Aggr() interface{} {
+	v := a.v
+	a.v = 0
+	return v
+}