Autovacuum active collector and test

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

collector/collector_test.go

@@ -49,6 +49,7 @@ func readMetric(m prometheus.Metric) MetricResult {
 func sanitizeQuery(q string) string {
 	q = strings.Join(strings.Fields(q), " ")
 	q = strings.Replace(q, "(", "\\(", -1)
+	q = strings.Replace(q, "?", "\\?", -1)
 	q = strings.Replace(q, ")", "\\)", -1)
 	q = strings.Replace(q, "[", "\\[", -1)
 	q = strings.Replace(q, "]", "\\]", -1)

collector/pg_stat_activity_autovacuum_active.go

@@ -0,0 +1,91 @@
+// Copyright 2023 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package collector
+
+import (
+	"context"
+
+	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const statActivityAutovacuumActiveSubsystem = "stat_activity_autovacuum_active"
+
+func init() {
+	registerCollector(statActivityAutovacuumActiveSubsystem, defaultDisabled, NewPGStatActivityAutovacuumActiveCollector)
+}
+
+type PGStatActivityAutovacuumActiveCollector struct {
+	log log.Logger
+}
+
+func NewPGStatActivityAutovacuumActiveCollector(config collectorConfig) (Collector, error) {
+	return &PGStatActivityAutovacuumActiveCollector{log: config.logger}, nil
+}
+
+var (
+	statActivityAutovacuumActiveWorkersCount = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, statActivityAutovacuumActiveSubsystem, "workers"),
+		"Current number of statActivityAutovacuumActive queries",
+		[]string{"phase", "mode"},
+		prometheus.Labels{},
+	)
+
+	statActivityAutovacuumActiveQuery = `
+	SELECT
+		v.phase,
+		CASE
+			when a.query ~ '^autovacuum.*to prevent wraparound' then 'wraparound'
+			when a.query ~* '^vacuum' then 'user'
+			when a.pid is null then 'idle'
+		ELSE 'regular'
+		END as mode,
+		count(1) as workers_count
+	FROM pg_stat_progress_vacuum v
+	LEFT JOIN pg_catalog.pg_stat_activity a using (pid)
+	GROUP BY 1,2
+	`
+)
+
+func (PGStatActivityAutovacuumActiveCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+	db := instance.getDB()
+	rows, err := db.QueryContext(ctx,
+		statActivityAutovacuumActiveQuery)
+
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		var phase, mode string
+		var workersCount float64
+
+		if err := rows.Scan(&phase, &mode, &workersCount); err != nil {
+			return err
+		}
+		labels := []string{phase, mode}
+
+		ch <- prometheus.MustNewConstMetric(
+			statActivityAutovacuumActiveWorkersCount,
+			prometheus.GaugeValue,
+			workersCount,
+			labels...,
+		)
+	}
+	if err := rows.Err(); err != nil {
+		return err
+	}
+	return nil
+}

collector/pg_stat_activity_autovacuum_active_test.go

@@ -0,0 +1,62 @@
+// Copyright 2023 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package collector
+
+import (
+	"context"
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
+	"github.com/smartystreets/goconvey/convey"
+)
+
+func TestPGStatActivityAutovacuumActiveCollector(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}
+	columns := []string{
+		"phase",
+		"mode",
+		"workers_count",
+	}
+	rows := sqlmock.NewRows(columns).
+		AddRow("Scanning heap", "regular", 2)
+	mock.ExpectQuery(sanitizeQuery(statActivityAutovacuumActiveQuery)).WillReturnRows(rows)
+
+	ch := make(chan prometheus.Metric)
+	go func() {
+		defer close(ch)
+		c := PGStatActivityAutovacuumActiveCollector{}
+
+		if err := c.Update(context.Background(), inst, ch); err != nil {
+			t.Errorf("Error calling PGStatActivityAutovacuumActiveCollector.Update: %s", err)
+		}
+	}()
+	expected := []MetricResult{
+		{labels: labelMap{"phase": "Scanning heap", "mode": "regular"}, value: 2, 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)
+	}
+}