From 14b0f6e496971a690ff0e4f458a921353b552c9f Mon Sep 17 00:00:00 2001
From: Jason Wilder <mail@jasonwilder.com>
Date: Fri, 16 Sep 2016 11:49:15 -0600
Subject: [PATCH] Fix panic in subscriber.Statistics

The tags passed into Statistics() calls are not supposed to be modified.
The balanceWriter in subscribers tried to modify them triggering a panic
because they can be nil.
---
 cmd/influxd/run/server_test.go | 44 ++++++++++++++++++++++++++++++++++
 services/subscriber/service.go |  5 ++--
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/cmd/influxd/run/server_test.go b/cmd/influxd/run/server_test.go
index 12e89f72e59..c7844d38a85 100644
--- a/cmd/influxd/run/server_test.go
+++ b/cmd/influxd/run/server_test.go
@@ -5608,6 +5608,50 @@ func TestServer_Query_ShowSeries(t *testing.T) {
 	}
 }
 
+func TestServer_Query_ShowStats(t *testing.T) {
+	t.Parallel()
+	s := OpenServer(NewConfig())
+	defer s.Close()
+
+	if err := s.CreateDatabaseAndRetentionPolicy("db0", newRetentionPolicySpec("rp0", 1, 0)); err != nil {
+		t.Fatal(err)
+	}
+	if err := s.MetaClient.SetDefaultRetentionPolicy("db0", "rp0"); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := s.MetaClient.CreateSubscription("db0", "rp0", "foo", "ALL", []string{"udp://localhost:9000"}); err != nil {
+		t.Fatal(err)
+	}
+
+	test := NewTest("db0", "rp0")
+	test.addQueries([]*Query{
+		&Query{
+			name:    `show shots`,
+			command: "SHOW STATS",
+			exp:     "subscriber", // Should see a subscriber stat in the json
+			pattern: true,
+		},
+	}...)
+
+	for i, query := range test.queries {
+		if i == 0 {
+			if err := test.init(s); err != nil {
+				t.Fatalf("test init failed: %s", err)
+			}
+		}
+		if query.skip {
+			t.Logf("SKIP:: %s", query.name)
+			continue
+		}
+		if err := query.Execute(s); err != nil {
+			t.Error(query.Error(err))
+		} else if !query.success() {
+			t.Error(query.failureMessage())
+		}
+	}
+}
+
 func TestServer_Query_ShowMeasurements(t *testing.T) {
 	t.Parallel()
 	s := OpenServer(NewConfig())
diff --git a/services/subscriber/service.go b/services/subscriber/service.go
index cb8b72a2762..53b3b61e9cc 100644
--- a/services/subscriber/service.go
+++ b/services/subscriber/service.go
@@ -417,10 +417,11 @@ func (b *balancewriter) WritePoints(p *coordinator.WritePointsRequest) error {
 func (b *balancewriter) Statistics(tags map[string]string) []models.Statistic {
 	statistics := make([]models.Statistic, len(b.stats))
 	for i := range b.stats {
-		tags["destination"] = b.stats[i].dest
+		subTags := b.defaultTags.Merge(tags)
+		subTags["destination"] = b.stats[i].dest
 		statistics[i] = models.Statistic{
 			Name: "subscriber",
-			Tags: b.defaultTags.Merge(tags),
+			Tags: subTags,
 			Values: map[string]interface{}{
 				statPointsWritten: atomic.LoadInt64(&b.stats[i].pointsWritten),
 				statWriteFailures: atomic.LoadInt64(&b.stats[i].failures),