postgres_exporter/collector/pg_replication_slot.go

118 lines
2.9 KiB
Go

// 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 replicationSlotSubsystem = "replication_slot"
func init() {
registerCollector(replicationSlotSubsystem, defaultEnabled, NewPGReplicationSlotCollector)
}
type PGReplicationSlotCollector struct {
log log.Logger
}
func NewPGReplicationSlotCollector(config collectorConfig) (Collector, error) {
return &PGReplicationSlotCollector{log: config.logger}, nil
}
var (
pgReplicationSlotCurrentWalDesc = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
replicationSlotSubsystem,
"slot_current_wal_lsn",
),
"current wal lsn value",
[]string{"slot_name"}, nil,
)
pgReplicationSlotCurrentFlushDesc = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
replicationSlotSubsystem,
"slot_confirmed_flush_lsn",
),
"last lsn confirmed flushed to the replication slot",
[]string{"slot_name"}, nil,
)
pgReplicationSlotIsActiveDesc = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
replicationSlotSubsystem,
"slot_is_active",
),
"whether the replication slot is active or not",
[]string{"slot_name"}, nil,
)
pgReplicationSlotQuery = `SELECT
slot_name,
pg_current_wal_lsn() - '0/0' AS current_wal_lsn,
coalesce(confirmed_flush_lsn, '0/0') - '0/0',
active
FROM
pg_replication_slots;`
)
func (PGReplicationSlotCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
db := instance.getDB()
rows, err := db.QueryContext(ctx,
pgReplicationSlotQuery)
if err != nil {
return err
}
defer rows.Close()
for rows.Next() {
var slotName string
var walLSN int64
var flushLSN int64
var isActive bool
if err := rows.Scan(&slotName, &walLSN, &flushLSN, &isActive); err != nil {
return err
}
isActiveValue := 0
if isActive {
isActiveValue = 1
}
ch <- prometheus.MustNewConstMetric(
pgReplicationSlotCurrentWalDesc,
prometheus.GaugeValue, float64(walLSN), slotName,
)
if isActive {
ch <- prometheus.MustNewConstMetric(
pgReplicationSlotCurrentFlushDesc,
prometheus.GaugeValue, float64(flushLSN), slotName,
)
}
ch <- prometheus.MustNewConstMetric(
pgReplicationSlotIsActiveDesc,
prometheus.GaugeValue, float64(isActiveValue), slotName,
)
}
if err := rows.Err(); err != nil {
return err
}
return nil
}