Gitlab Collector: Autovacuum collector and test (#840)

* Autovacuum collector and test Signed-off-by: Felix Yuan <felix.yuan@reddit.com> * Update collector/pg_stat_activity_autovacuum.go Co-authored-by: Joe Adams <github@joeadams.io> Signed-off-by: Felix Yuan <felix.yuan@reddit.com> * Update collector/pg_stat_activity_autovacuum.go Co-authored-by: Joe Adams <github@joeadams.io> Signed-off-by: Felix Yuan <felix.yuan@reddit.com> * Use timestamp seconds Signed-off-by: Felix Yuan <felix.yuan@reddit.com> * query formating Signed-off-by: Felix Yuan <felix.yuan@reddit.com> * SQL format Signed-off-by: Felix Yuan <felix.yuan@reddit.com> * Loosen autovacuum query Signed-off-by: Felix Yuan <felix.yuan@reddit.com> --------- Signed-off-by: Felix Yuan <felix.yuan@reddit.com> Co-authored-by: Joe Adams <github@joeadams.io>

Author: Sticksman

collector/pg_stat_activity_autovacuum.go

@@ -0,0 +1,84 @@
+// 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 statActivityAutovacuumSubsystem = "stat_activity_autovacuum"
+
+func init() {
+registerCollector(statActivityAutovacuumSubsystem, defaultDisabled, NewPGStatActivityAutovacuumCollector)
+}
+
+type PGStatActivityAutovacuumCollector struct {
+log log.Logger
+}
+
+func NewPGStatActivityAutovacuumCollector(config collectorConfig) (Collector, error) {
+return &PGStatActivityAutovacuumCollector{log: config.logger}, nil
+}
+
+var (
+statActivityAutovacuumAgeInSeconds = prometheus.NewDesc(
+prometheus.BuildFQName(namespace, statActivityAutovacuumSubsystem, "timestamp_seconds"),
+"Start timestamp of the vacuum process in seconds",
+[]string{"relname"},
+prometheus.Labels{},
+)
+
+statActivityAutovacuumQuery = `
+ SELECT
+SPLIT_PART(query, '.', 2) AS relname,
+EXTRACT(xact_start) AS timestamp_seconds
+ FROM
+	pg_catalog.pg_stat_activity
+ WHERE
+query LIKE 'autovacuum:%'
+`
+)
+
+func (PGStatActivityAutovacuumCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+db := instance.getDB()
+rows, err := db.QueryContext(ctx,
+statActivityAutovacuumQuery)
+
+if err != nil {
+return err
+}
+defer rows.Close()
+
+for rows.Next() {
+var relname string
+var ageInSeconds float64
+
+if err := rows.Scan(&relname, &ageInSeconds); err != nil {
+return err
+}
+
+ch <- prometheus.MustNewConstMetric(
+statActivityAutovacuumAgeInSeconds,
+prometheus.GaugeValue,
+ageInSeconds, relname,
+)
+}
+if err := rows.Err(); err != nil {
+return err
+}
+return nil
+}

collector/pg_stat_activity_autovacuum_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 TestPGStatActivityAutovacuumCollector(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{
+"relname",
+"timestamp_seconds",
+}
+rows := sqlmock.NewRows(columns).
+AddRow("test", 3600)
+
+mock.ExpectQuery(sanitizeQuery(statActivityAutovacuumQuery)).WillReturnRows(rows)
+
+ch := make(chan prometheus.Metric)
+go func() {
+defer close(ch)
+c := PGStatActivityAutovacuumCollector{}
+
+if err := c.Update(context.Background(), inst, ch); err != nil {
+t.Errorf("Error calling PGStatActivityAutovacuumCollector.Update: %s", err)
+}
+}()
+expected := []MetricResult{
+{labels: labelMap{"relname": "test"}, value: 3600, 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)
+}
+}