postgres_exporter/collector/pg_wal.go

85 lines
1.9 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/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
}