Skip nulls and log a message

Signed-off-by: Felix Yuan <felix.yuan@reddit.com>

Author: Sticksman

collector/pg_stat_walreceiver.go

@@ -18,6 +18,7 @@ import (
 	"fmt"
 
 	"github.com/go-kit/log"
+	"github.com/go-kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -158,132 +159,147 @@ func (c *PGStatWalReceiverCollector) Update(ctx context.Context, instance *insta
 			}
 		}
 		if !upstreamHost.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because upstream host is null")
 			continue
 		}
 
 		if !slotName.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because slotname host is null")
 			continue
 		}
 		labels := []string{upstreamHost.String, slotName.String}
+		if !status.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because status is null")
+			continue
+		}
 
-		statusMetric := -3.0
-		if status.Valid {
-			switch status.String {
-			case "stopped":
-				statusMetric = 0.0
-				break
-			case "starting":
-				statusMetric = 1.0
-				break
-			case "streaming":
-				statusMetric = 2.0
-				break
-			case "waiting":
-				statusMetric = 3.0
-				break
-			case "restarting":
-				statusMetric = 4.0
-				break
-			case "stopping":
-				statusMetric = -1.0
-				break
-			default:
-				statusMetric = -2.0
-				break
-			}
+		var statusMetric float64
+		switch status.String {
+		case "stopped":
+			statusMetric = 0.0
+			break
+		case "starting":
+			statusMetric = 1.0
+			break
+		case "streaming":
+			statusMetric = 2.0
+			break
+		case "waiting":
+			statusMetric = 3.0
+			break
+		case "restarting":
+			statusMetric = 4.0
+			break
+		case "stopping":
+			statusMetric = -1.0
+			break
+		default:
+			statusMetric = -2.0
+			break
+		}
+
+		if !receiveStartLsn.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because receive_start_lsn is null")
+			continue
+		}
+		if !receiveStartTli.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because receive_start_tli is null")
+			continue
+		}
+		if hasFlushedLSN && !flushedLsn.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because flushed_lsn is null")
+			continue
+		}
+		if !receivedTli.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because received_tli is null")
+			continue
+		}
+		if !lastMsgSendTime.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because last_msg_send_time is null")
+			continue
+		}
+		if !lastMsgReceiptTime.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because last_msg_receipt_time is null")
+			continue
 		}
+		if !latestEndLsn.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because latest_end_lsn is null")
+			continue
+		}
+		if !latestEndTime.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because latest_end_time is null")
+			continue
+		}
+		if !upstreamNode.Valid {
+			level.Debug(c.log).Log("msg", "Skipping wal receiver stats because upstream_node is null")
+			continue
+		}
+
+		receiveStartLsnMetric := float64(receiveStartLsn.Int64)
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverStatus,
 			prometheus.GaugeValue,
 			statusMetric,
 			labels...)
 
-		receiveStartLsnMetric := 0.0
-		if receiveStartLsn.Valid {
-			receiveStartLsnMetric = float64(receiveStartLsn.Int64)
-		}
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverReceiveStartLsn,
 			prometheus.CounterValue,
 			receiveStartLsnMetric,
 			labels...)
 
-		receiveStartTliMetric := 0.0
-		if receiveStartTli.Valid {
-			receiveStartTliMetric = float64(receiveStartTli.Int64)
-		}
+		receiveStartTliMetric := float64(receiveStartTli.Int64)
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverReceiveStartTli,
 			prometheus.GaugeValue,
 			receiveStartTliMetric,
 			labels...)
 
 		if hasFlushedLSN {
-			flushedLsnMetric := 0.0
-			if flushedLsn.Valid {
-				flushedLsnMetric = float64(flushedLsn.Int64)
-			}
+			flushedLsnMetric := float64(flushedLsn.Int64)
 			ch <- prometheus.MustNewConstMetric(
 				statWalReceiverFlushedLSN,
 				prometheus.CounterValue,
 				flushedLsnMetric,
 				labels...)
 		}
 
-		receivedTliMetric := 0.0
-		if receivedTli.Valid {
-			receivedTliMetric = float64(receivedTli.Int64)
-		}
+		receivedTliMetric := float64(receivedTli.Int64)
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverReceivedTli,
 			prometheus.GaugeValue,
 			receivedTliMetric,
 			labels...)
 
-		lastMsgSendTimeMetric := 0.0
-		if lastMsgSendTime.Valid {
-			lastMsgSendTimeMetric = float64(lastMsgSendTime.Float64)
-		}
+		lastMsgSendTimeMetric := float64(lastMsgSendTime.Float64)
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverLastMsgSendTime,
 			prometheus.CounterValue,
 			lastMsgSendTimeMetric,
 			labels...)
 
-		lastMsgReceiptTimeMetric := 0.0
-		if lastMsgReceiptTime.Valid {
-			lastMsgReceiptTimeMetric = float64(lastMsgReceiptTime.Float64)
-		}
+		lastMsgReceiptTimeMetric := float64(lastMsgReceiptTime.Float64)
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverLastMsgReceiptTime,
 			prometheus.CounterValue,
 			lastMsgReceiptTimeMetric,
 			labels...)
 
-		latestEndLsnMetric := 0.0
-		if latestEndLsn.Valid {
-			latestEndLsnMetric = float64(latestEndLsn.Int64)
-		}
+		latestEndLsnMetric := float64(latestEndLsn.Int64)
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverLatestEndLsn,
 			prometheus.CounterValue,
 			latestEndLsnMetric,
 			labels...)
 
-		latestEndTimeMetric := 0.0
-		if latestEndTime.Valid {
-			latestEndTimeMetric = float64(latestEndTime.Float64)
-		}
+		latestEndTimeMetric := float64(latestEndTime.Float64)
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverLatestEndTime,
 			prometheus.CounterValue,
 			latestEndTimeMetric,
 			labels...)
 
-		upstreamNodeMetric := 0.0
-		if upstreamNode.Valid {
-			upstreamNodeMetric = float64(upstreamNode.Int64)
-		}
+		upstreamNodeMetric := float64(upstreamNode.Int64)
 		ch <- prometheus.MustNewConstMetric(
 			statWalReceiverUpstreamNode,
 			prometheus.GaugeValue,

collector/pg_stat_walreceiver_test.go

@@ -186,86 +186,3 @@ func TestPGStatWalReceiverCollectorWithNoFlushedLSN(t *testing.T) {
 	}
 
 }
-
-func TestPGStatWalReceiverCollectorWithFlushedLSNNull(t *testing.T) {
-	db, mock, err := sqlmock.New()
-	if err != nil {
-		t.Fatalf("Error opening a stub db connection: %s", err)
-	}
-	defer db.Close()
-
-	inst := &instance{db: db}
-	infoSchemaColumns := []string{
-		"column_name",
-	}
-
-	infoSchemaRows := sqlmock.NewRows(infoSchemaColumns).
-		AddRow(
-			"flushed_lsn",
-		)
-
-	mock.ExpectQuery(sanitizeQuery(pgStatWalColumnQuery)).WillReturnRows(infoSchemaRows)
-
-	columns := []string{
-		"upstream_host",
-		"slot_name",
-		"status",
-		"receive_start_lsn",
-		"receive_start_tli",
-		"flushed_lsn",
-		"received_tli",
-		"last_msg_send_time",
-		"last_msg_receipt_time",
-		"latest_end_lsn",
-		"latest_end_time",
-		"upstream_node",
-	}
-	rows := sqlmock.NewRows(columns).
-		AddRow(
-			"foo",
-			"bar",
-			nil,
-			nil,
-			nil,
-			nil,
-			nil,
-			nil,
-			nil,
-			nil,
-			nil,
-			nil,
-		)
-	mock.ExpectQuery(sanitizeQuery(queryWithFlushedLSN)).WillReturnRows(rows)
-
-	ch := make(chan prometheus.Metric)
-	go func() {
-		defer close(ch)
-		c := PGStatWalReceiverCollector{}
-
-		if err := c.Update(context.Background(), inst, ch); err != nil {
-			t.Errorf("Error calling PgStatWalReceiverCollector.Update: %s", err)
-		}
-	}()
-	expected := []MetricResult{
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: -3.0, metricType: dto.MetricType_GAUGE},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_COUNTER},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_GAUGE},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_COUNTER},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_GAUGE},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_COUNTER},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_COUNTER},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_COUNTER},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_COUNTER},
-		{labels: labelMap{"upstream_host": "foo", "slot_name": "bar"}, value: 0, metricType: dto.MetricType_GAUGE},
-	}
-	convey.Convey("Metrics comparison", t, func() {
-		for _, expect := range expected {
-			m := readMetric(<-ch)
-			convey.So(expect, convey.ShouldResemble, m)
-		}
-	})
-	if err := mock.ExpectationsWereMet(); err != nil {
-		t.Errorf("there were unfulfilled exceptions: %s", err)
-	}
-
-}