From 33634fb813b4e57adcc83b91900cb9d21f95985e Mon Sep 17 00:00:00 2001 From: Felix Yuan Date: Wed, 28 Jun 2023 11:21:30 -0700 Subject: [PATCH 1/3] Xlog location collector and test Signed-off-by: Felix Yuan --- collector/pg_xlog_location.go | 80 ++++++++++++++++++++++++++++++ collector/pg_xlog_location_test.go | 61 +++++++++++++++++++++++ 2 files changed, 141 insertions(+) create mode 100644 collector/pg_xlog_location.go create mode 100644 collector/pg_xlog_location_test.go diff --git a/collector/pg_xlog_location.go b/collector/pg_xlog_location.go new file mode 100644 index 000000000..b281d7a51 --- /dev/null +++ b/collector/pg_xlog_location.go @@ -0,0 +1,80 @@ +// 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 xlogLocationSubsystem = "xlog_location" + +func init() { + registerCollector(xlogLocationSubsystem, defaultDisabled, NewPGXlogLocationCollector) +} + +type PGXlogLocationCollector struct { + log log.Logger +} + +func NewPGXlogLocationCollector(config collectorConfig) (Collector, error) { + return &PGXlogLocationCollector{log: config.logger}, nil +} + +var ( + xlogLocationBytes = prometheus.NewDesc( + prometheus.BuildFQName(namespace, xlogLocationSubsystem, "bytes"), + "Postgres LSN (log sequence number) being generated on primary or replayed on replica (truncated to low 52 bits)", + []string{}, + prometheus.Labels{}, + ) + + xlogLocationQuery = ` + SELECT CASE + WHEN pg_is_in_recovery() THEN (pg_last_xlog_replay_location() - '0/0') % (2^52)::bigint + ELSE (pg_current_xlog_location() - '0/0') % (2^52)::bigint + END AS bytes + ` +) + +func (PGXlogLocationCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error { + db := instance.getDB() + rows, err := db.QueryContext(ctx, + xlogLocationQuery) + + if err != nil { + return err + } + defer rows.Close() + + for rows.Next() { + var bytes float64 + + if err := rows.Scan(&bytes); err != nil { + return err + } + + ch <- prometheus.MustNewConstMetric( + xlogLocationBytes, + prometheus.CounterValue, + bytes, + ) + } + if err := rows.Err(); err != nil { + return err + } + return nil +} diff --git a/collector/pg_xlog_location_test.go b/collector/pg_xlog_location_test.go new file mode 100644 index 000000000..9071a2cc1 --- /dev/null +++ b/collector/pg_xlog_location_test.go @@ -0,0 +1,61 @@ +// 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 TestPGXlogLocationCollector(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{ + "bytes", + } + rows := sqlmock.NewRows(columns). + AddRow(53401) + + mock.ExpectQuery(sanitizeQuery(xlogLocationQuery)).WillReturnRows(rows) + + ch := make(chan prometheus.Metric) + go func() { + defer close(ch) + c := PGXlogLocationCollector{} + + if err := c.Update(context.Background(), inst, ch); err != nil { + t.Errorf("Error calling PGXlogLocationCollector.Update: %s", err) + } + }() + expected := []MetricResult{ + {labels: labelMap{}, value: 53401, metricType: dto.MetricType_COUNTER}, + } + 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) + } +} From e4be608ead64cb8fb2f1dbfdb6eb3f1176736a8f Mon Sep 17 00:00:00 2001 From: Felix Yuan Date: Wed, 28 Jun 2023 11:25:23 -0700 Subject: [PATCH 2/3] Add more escapes Signed-off-by: Felix Yuan --- collector/collector_test.go | 1 + 1 file changed, 1 insertion(+) diff --git a/collector/collector_test.go b/collector/collector_test.go index 00c21ed23..18101f00e 100644 --- a/collector/collector_test.go +++ b/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) From 7957fb440a1c0f841c2aa24024f5e5cd1644074f Mon Sep 17 00:00:00 2001 From: Felix Yuan Date: Mon, 10 Jul 2023 10:38:09 -0700 Subject: [PATCH 3/3] Change to Gauge Signed-off-by: Felix Yuan --- collector/pg_xlog_location.go | 2 +- collector/pg_xlog_location_test.go | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/collector/pg_xlog_location.go b/collector/pg_xlog_location.go index b281d7a51..92ac44acb 100644 --- a/collector/pg_xlog_location.go +++ b/collector/pg_xlog_location.go @@ -69,7 +69,7 @@ func (PGXlogLocationCollector) Update(ctx context.Context, instance *instance, c ch <- prometheus.MustNewConstMetric( xlogLocationBytes, - prometheus.CounterValue, + prometheus.GaugeValue, bytes, ) } diff --git a/collector/pg_xlog_location_test.go b/collector/pg_xlog_location_test.go index 9071a2cc1..561a7df94 100644 --- a/collector/pg_xlog_location_test.go +++ b/collector/pg_xlog_location_test.go @@ -47,7 +47,7 @@ func TestPGXlogLocationCollector(t *testing.T) { } }() expected := []MetricResult{ - {labels: labelMap{}, value: 53401, metricType: dto.MetricType_COUNTER}, + {labels: labelMap{}, value: 53401, metricType: dto.MetricType_GAUGE}, } convey.Convey("Metrics comparison", t, func() { for _, expect := range expected {