From 4fec6a9608889843893baee5613590b80edf39cb Mon Sep 17 00:00:00 2001
From: Sean Chittenden <sean@chittenden.org>
Date: Fri, 25 Mar 2016 13:26:29 -0700
Subject: [PATCH] Guard against very small or negative rates

Pointed out by: slackpad
---
 lib/cluster.go      |  4 ++++
 lib/cluster_test.go | 11 ++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/cluster.go b/lib/cluster.go
index 0062c61375..33a7788c78 100644
--- a/lib/cluster.go
+++ b/lib/cluster.go
@@ -14,6 +14,10 @@ func RandomStagger(intv time.Duration) time.Duration {
 // order to target an aggregate number of actions per second across the whole
 // cluster.
 func RateScaledInterval(rate float64, min time.Duration, n int) time.Duration {
+	const minRate = 1 / 86400 // 1/(1 * time.Day)
+	if rate <= minRate {
+		return min
+	}
 	interval := time.Duration(float64(time.Second) * float64(n) / rate)
 	if interval < min {
 		return min
diff --git a/lib/cluster_test.go b/lib/cluster_test.go
index 40949d0204..d517e4677f 100644
--- a/lib/cluster_test.go
+++ b/lib/cluster_test.go
@@ -16,7 +16,7 @@ func TestRandomStagger(t *testing.T) {
 }
 
 func TestRateScaledInterval(t *testing.T) {
-	min := 1 * time.Second
+	const min = 1 * time.Second
 	rate := 200.0
 	if v := RateScaledInterval(rate, min, 0); v != min {
 		t.Fatalf("Bad: %v", v)
@@ -36,4 +36,13 @@ func TestRateScaledInterval(t *testing.T) {
 	if v := RateScaledInterval(rate, min, 10000); v != 50*time.Second {
 		t.Fatalf("Bad: %v", v)
 	}
+	if v := RateScaledInterval(0, min, 10000); v != min {
+		t.Fatalf("Bad: %v", v)
+	}
+	if v := RateScaledInterval(0.0, min, 10000); v != min {
+		t.Fatalf("Bad: %v", v)
+	}
+	if v := RateScaledInterval(-1, min, 10000); v != min {
+		t.Fatalf("Bad: %v", v)
+	}
 }