prometheus2graphite.patch

diff --git a/storage/remote/graphite/client.go b/storage/remote/graphite/client.go
index 7aa5a3e..f91de22 100644
--- a/storage/remote/graphite/client.go
+++ b/storage/remote/graphite/client.go
@@ -47,7 +47,9 @@ func pathFromMetric(m model.Metric, prefix string) string {
        var buffer bytes.Buffer
 
        buffer.WriteString(prefix)
-       buffer.WriteString(escape(m[model.MetricNameLabel]))
+       // Replace _ by . to spread metrics in Graphite.
+       buffer.WriteString(
+               strings.Replace(escape(m[model.MetricNameLabel]), "_", ".", -1))
 
        // We want to sort the labels.
        labels := make(model.LabelNames, 0, len(m))
diff --git a/storage/remote/graphite/client_test.go b/storage/remote/graphite/client_test.go
index cacf667..1766619 100644
--- a/storage/remote/graphite/client_test.go
+++ b/storage/remote/graphite/client_test.go
@@ -47,7 +47,7 @@ func TestEscape(t *testing.T) {
 
 func TestPathFromMetric(t *testing.T) {
        expected := ("prefix." +
-               "test:metric" +
+               "test.metric" +
                ".many_chars=abc!ABC:012-3!45%C3%B667~89%2E%2F\\(\\)\\{\\}\\,%3D%2E\\\"\\\\" +
                ".testlabel=test:value")
        actual := pathFromMetric(metric, "prefix.")