Add Amazon Aurora PostgreSQL support

CHANGELOG.md

@@ -1,7 +1,7 @@
 ## main / (unreleased)
 
 * [CHANGE] ...
-* [FEATURE] ...
+* [FEATURE] Add Amazon Aurora PostgreSQL support: auto-detection via `aurora_version()` and 9 new `aurora_*` collectors, all disabled by default.
 * [ENHANCEMENT] ...
 * [BUGFIX] ...
 

README.md

@@ -196,6 +196,39 @@ This will build the docker image as `prometheuscommunity/postgres_exporter:${bra
 * `[no-]collector.xlog_location`
   Enable the `xlog_location` collector (default: disabled).
 
+#### Amazon Aurora PostgreSQL collectors
+
+These collectors expose metrics that only exist on Amazon Aurora PostgreSQL.
+They are all disabled by default and detect Aurora automatically — when
+enabled on a non-Aurora server they silently emit no data (no log noise).
+
+* `[no-]collector.aurora_replica_status`
+  Replica lag, replay latency, pending read IOs from `aurora_replica_status()`. (default: disabled)
+
+* `[no-]collector.aurora_global_db_status`
+  Per-region durability lag and RPO lag from `aurora_global_db_status()`. (default: disabled)
+
+* `[no-]collector.aurora_global_db_instance_status`
+  Per-instance visibility lag from `aurora_global_db_instance_status()`. (default: disabled)
+
+* `[no-]collector.aurora_stat_database`
+  Aurora-specific per-database I/O counters (storage / optimized reads cache / local) from `aurora_stat_database()`. (default: disabled)
+
+* `[no-]collector.aurora_stat_bgwriter`
+  Aurora Optimized Reads cache writes from `aurora_stat_bgwriter()`. (default: disabled)
+
+* `[no-]collector.aurora_stat_commit_latency`
+  Cumulative per-database commit latency from `aurora_stat_get_db_commit_latency()`. (default: disabled)
+
+* `[no-]collector.aurora_stat_dml_activity`
+  Per-database SELECT/INSERT/UPDATE/DELETE counts and latency from `aurora_stat_dml_activity()`. (default: disabled)
+
+* `[no-]collector.aurora_stat_optimized_reads_cache`
+  Aurora Optimized Reads cache total/used size from `aurora_stat_optimized_reads_cache()`. (default: disabled)
+
+* `[no-]collector.aurora_stat_logical_wal_cache`
+  Per-replication-slot WAL cache hits/misses from `aurora_stat_logical_wal_cache()`. (default: disabled)
+
 * `config.file`
   Set the config file path. Default is `postgres_exporter.yml`
 

collector/aurora_global_db_instance_status.go

@@ -0,0 +1,84 @@
+// Copyright 2025 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"
+	"database/sql"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// aurora_global_db_instance_status() exposes per-instance lag across regions
+// in an Aurora Global Database. Disabled by default; only useful on Aurora.
+const auroraGlobalDBInstanceSubsystem = "aurora_global_db_instance"
+
+func init() {
+	registerCollector("aurora_global_db_instance_status", defaultDisabled, NewAuroraGlobalDBInstanceStatusCollector)
+}
+
+type AuroraGlobalDBInstanceStatusCollector struct{}
+
+func NewAuroraGlobalDBInstanceStatusCollector(collectorConfig) (Collector, error) {
+	return &AuroraGlobalDBInstanceStatusCollector{}, nil
+}
+
+var (
+	auroraGlobalDBInstanceVisibilityLagDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, auroraGlobalDBInstanceSubsystem, "visibility_lag_milliseconds"),
+		"How far this DB instance is lagging behind the writer DB instance in milliseconds. NULL for the writer.",
+		[]string{"server_id", "aws_region"}, nil,
+	)
+
+	auroraGlobalDBInstanceStatusQuery = `SELECT
+		server_id,
+		aws_region,
+		visibility_lag_in_msec
+	FROM aurora_global_db_instance_status()`
+)
+
+func (c AuroraGlobalDBInstanceStatusCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+	if !instance.isAurora {
+		return ErrNoData
+	}
+	rows, err := instance.getDB().QueryContext(ctx, auroraGlobalDBInstanceStatusQuery)
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	var found bool
+	for rows.Next() {
+		found = true
+
+		var serverID, awsRegion string
+		var visibilityLag sql.NullFloat64
+
+		if err := rows.Scan(&serverID, &awsRegion, &visibilityLag); err != nil {
+			return err
+		}
+
+		if visibilityLag.Valid {
+			ch <- prometheus.MustNewConstMetric(auroraGlobalDBInstanceVisibilityLagDesc, prometheus.GaugeValue, visibilityLag.Float64, serverID, awsRegion)
+		}
+	}
+
+	if err := rows.Err(); err != nil {
+		return err
+	}
+	if !found {
+		return ErrNoData
+	}
+	return nil
+}

collector/aurora_global_db_instance_status_test.go

@@ -0,0 +1,81 @@
+// Copyright 2025 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"
+	"github.com/smartystreets/goconvey/convey"
+)
+
+func TestAuroraGlobalDBInstanceStatusCollector(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, isAurora: true}
+
+	columns := []string{"server_id", "aws_region", "visibility_lag_in_msec"}
+	rows := sqlmock.NewRows(columns).
+		AddRow("writer", "eu-west-1", nil). // writer: NULL lag, skipped
+		AddRow("reader-1", "eu-west-1", 6.0).
+		AddRow("reader-2", "eu-central-1", 996.0)
+	mock.ExpectQuery(sanitizeQuery(auroraGlobalDBInstanceStatusQuery)).WillReturnRows(rows)
+
+	ch := make(chan prometheus.Metric)
+	go func() {
+		defer close(ch)
+		c := AuroraGlobalDBInstanceStatusCollector{}
+		if err := c.Update(context.Background(), inst, ch); err != nil {
+			t.Errorf("Error calling Update: %s", err)
+		}
+	}()
+
+	got := 0
+	for range ch {
+		got++
+	}
+	convey.Convey("Metrics count", t, func() {
+		convey.So(got, convey.ShouldEqual, 2) // writer skipped (NULL), 2 readers emitted
+		if err := mock.ExpectationsWereMet(); err != nil {
+			t.Errorf("Unfulfilled expectations: %s", err)
+		}
+	})
+}
+
+func TestAuroraGlobalDBInstanceStatusCollectorNotAurora(t *testing.T) {
+	db, _, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("Error opening a stub db connection: %s", err)
+	}
+	defer db.Close()
+
+	inst := &instance{db: db, isAurora: false}
+
+	ch := make(chan prometheus.Metric)
+	go func() {
+		defer close(ch)
+		c := AuroraGlobalDBInstanceStatusCollector{}
+		if err := c.Update(context.Background(), inst, ch); err != ErrNoData {
+			t.Errorf("Expected ErrNoData, got: %v", err)
+		}
+	}()
+	for range ch {
+	}
+}

collector/aurora_global_db_status.go

@@ -0,0 +1,93 @@
+// Copyright 2025 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"
+	"database/sql"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// auroraGlobalDBSubsystem exposes metrics from Aurora PostgreSQL's
+// aurora_global_db_status() function. Disabled by default; only useful for
+// Aurora Global Database deployments.
+const auroraGlobalDBSubsystem = "aurora_global_db"
+
+func init() {
+	registerCollector("aurora_global_db_status", defaultDisabled, NewAuroraGlobalDBStatusCollector)
+}
+
+type AuroraGlobalDBStatusCollector struct{}
+
+func NewAuroraGlobalDBStatusCollector(collectorConfig) (Collector, error) {
+	return &AuroraGlobalDBStatusCollector{}, nil
+}
+
+var (
+	auroraGlobalDurabilityLagDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, auroraGlobalDBSubsystem, "durability_lag_milliseconds"),
+		"Storage lag vs primary cluster in milliseconds (-1 for the primary cluster).",
+		[]string{"aws_region"}, nil,
+	)
+	auroraGlobalRPOLagDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, auroraGlobalDBSubsystem, "rpo_lag_milliseconds"),
+		"Recovery point objective lag in milliseconds (-1 for the primary cluster).",
+		[]string{"aws_region"}, nil,
+	)
+
+	auroraGlobalDBStatusQuery = `SELECT
+		aws_region,
+		durability_lag_in_msec,
+		rpo_lag_in_msec
+	FROM aurora_global_db_status()`
+)
+
+func (c AuroraGlobalDBStatusCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+	if !instance.isAurora {
+		return ErrNoData
+	}
+	rows, err := instance.getDB().QueryContext(ctx, auroraGlobalDBStatusQuery)
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	var found bool
+	for rows.Next() {
+		found = true
+
+		var awsRegion string
+		var durabilityLag, rpoLag sql.NullFloat64
+
+		if err := rows.Scan(&awsRegion, &durabilityLag, &rpoLag); err != nil {
+			return err
+		}
+
+		if durabilityLag.Valid {
+			ch <- prometheus.MustNewConstMetric(auroraGlobalDurabilityLagDesc, prometheus.GaugeValue, durabilityLag.Float64, awsRegion)
+		}
+		if rpoLag.Valid {
+			ch <- prometheus.MustNewConstMetric(auroraGlobalRPOLagDesc, prometheus.GaugeValue, rpoLag.Float64, awsRegion)
+		}
+	}
+
+	if err := rows.Err(); err != nil {
+		return err
+	}
+	if !found {
+		return ErrNoData
+	}
+	return nil
+}