Merge pull request #25 from ContaAzul/new-metrics

New Metric: Not granted locks

Author: diogonicoleti

gauges/locks.go

@@ -11,11 +11,12 @@ type lockCountWithMode struct {
 	Count float64 `db:"count"`
 }
 
+// Locks returns the number of locks by mode
 func (g *Gauges) Locks() *prometheus.GaugeVec {
 	var gauge = prometheus.NewGaugeVec(
 		prometheus.GaugeOpts{
 			Name:        "postgresql_lock_count",
-			Help:        "count of locks by mode",
+			Help:        "Number of locks by mode",
 			ConstLabels: g.labels,
 		},
 		[]string{"mode"},
@@ -47,3 +48,24 @@ func (g *Gauges) Locks() *prometheus.GaugeVec {
 	}()
 	return gauge
 }
+
+// NotGrantedLocks returns the number of not granted locks
+func (g *Gauges) NotGrantedLocks() prometheus.Gauge {
+	return g.new(
+		prometheus.GaugeOpts{
+			Name:        "postgresql_not_granted_locks",
+			Help:        "Number of not granted locks",
+			ConstLabels: g.labels,
+		},
+		`
+			SELECT count(*) as count
+			FROM pg_locks
+			WHERE NOT granted
+			AND database = (
+				SELECT datid
+				FROM pg_stat_database
+				WHERE datname = current_database()
+			);
+		`,
+	)
+}

gauges/locks_test.go

@@ -15,3 +15,13 @@ func TestLocks(t *testing.T) {
 	assertGreaterThan(t, -1, metrics[0])
 	assertNoErrs(t, gauges)
 }
+
+func TestNotGrantedLocks(t *testing.T) {
+	var assert = assert.New(t)
+	_, gauges, close := prepare(t)
+	defer close()
+	var metrics = evaluate(t, gauges.NotGrantedLocks())
+	assert.Len(metrics, 1)
+	assertGreaterThan(t, -1, metrics[0])
+	assertNoErrs(t, gauges)
+}