more comments

Signed-off-by: Zachary Caldarola <zmc2005@gmail.com>

Author: sheldor14

collector/pg_replication_slots.go renamed to collector/replication_slots.go

@@ -44,16 +44,22 @@ var pgReplicationSlot = map[string]*prometheus.Desc{
 "last lsn confirmed flushed to the replication slot",
 []string{"slot_name"}, nil,
 ),
+"is_active": prometheus.NewDesc(
+"pg_replication_slot_is_active",
+"last lsn confirmed flushed to the replication slot",
+[]string{"slot_name"}, nil,
+),
 }
 
 func (PGReplicationSlotCollector) Update(ctx context.Context, db *sql.DB, ch chan<- prometheus.Metric) error {
 rows, err := db.QueryContext(ctx,
 `SELECT
 slot_name,
-pg_current_wal_lsn() AS current_wal_lsn,
-confirmed_flush_lsn
-FROM
-pg_replication_slots;`)
+pg_current_wal_lsn() - '0/0' AS current_wal_lsn,
+coalesce(confirmed_flush_lsn, '0/0') - '0/0',
+active
+FROM
+pg_replication_slots;`)
 if err != nil {
 return err
 }
@@ -63,17 +69,24 @@ func (PGReplicationSlotCollector) Update(ctx context.Context, db *sql.DB, ch cha
 var slot_name string
 var wal_lsn int64
 var flush_lsn int64
-if err := rows.Scan(&slot_name, &wal_lsn, &flush_lsn); err != nil {
+var is_active int
+if err := rows.Scan(&slot_name, &wal_lsn, &flush_lsn, &is_active); err != nil {
 return err
 }
 
 ch <- prometheus.MustNewConstMetric(
 pgReplicationSlot["current_wal_lsn"],
 prometheus.GaugeValue, float64(wal_lsn), slot_name,
 )
+if (is_active == 1) {
+ch <- prometheus.MustNewConstMetric(
+pgReplicationSlot["confirmed_flush_lsn"],
+prometheus.GaugeValue, float64(flush_lsn), slot_name,
+)
+}
 ch <- prometheus.MustNewConstMetric(
-pgReplicationSlot["confirmed_flush_lsn"],
-prometheus.GaugeValue, float64(flush_lsn), slot_name,
+pgReplicationSlot["is_active"],
+prometheus.GaugeValue, int(flush_lsn), slot_name,
 )
 }
 if err := rows.Err(); err != nil {