diff --git a/collector/pg_wal.go b/collector/pg_wal.go new file mode 100644 index 000000000..afa8fcef6 --- /dev/null +++ b/collector/pg_wal.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/prometheus/client_golang/prometheus" +) + +const walSubsystem = "wal" + +func init() { + registerCollector(walSubsystem, defaultEnabled, NewPGWALCollector) +} + +type PGWALCollector struct { +} + +func NewPGWALCollector(config collectorConfig) (Collector, error) { + return &PGWALCollector{}, nil +} + +var ( + pgWALSegments = prometheus.NewDesc( + prometheus.BuildFQName( + namespace, + walSubsystem, + "segments", + ), + "Number of WAL segments", + []string{}, nil, + ) + pgWALSize = prometheus.NewDesc( + prometheus.BuildFQName( + namespace, + walSubsystem, + "size_bytes", + ), + "Total size of WAL segments", + []string{}, nil, + ) + + pgWALQuery = ` + SELECT + COUNT(*) AS segments, + SUM(size) AS size + FROM pg_ls_waldir() + WHERE name ~ '^[0-9A-F]{24}$'` +) + +func (c PGWALCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error { + db := instance.getDB() + row := db.QueryRowContext(ctx, + pgWALQuery, + ) + + var segments uint64 + var size uint64 + err := row.Scan(&segments, &size) + if err != nil { + return err + } + ch <- prometheus.MustNewConstMetric( + pgWALSegments, + prometheus.GaugeValue, float64(segments), + ) + ch <- prometheus.MustNewConstMetric( + pgWALSize, + prometheus.GaugeValue, float64(size), + ) + return nil +} diff --git a/collector/pg_wal_test.go b/collector/pg_wal_test.go new file mode 100644 index 000000000..745105a13 --- /dev/null +++ b/collector/pg_wal_test.go @@ -0,0 +1,63 @@ +// 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 TestPgWALCollector(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{"segments", "size"} + rows := sqlmock.NewRows(columns). + AddRow(47, 788529152) + mock.ExpectQuery(sanitizeQuery(pgWALQuery)).WillReturnRows(rows) + + ch := make(chan prometheus.Metric) + go func() { + defer close(ch) + c := PGWALCollector{} + + if err := c.Update(context.Background(), inst, ch); err != nil { + t.Errorf("Error calling PGWALCollector.Update: %s", err) + } + }() + + expected := []MetricResult{ + {labels: labelMap{}, value: 47, metricType: dto.MetricType_GAUGE}, + {labels: labelMap{}, value: 788529152, 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) + } +}