mirror of
https://github.com/prometheus-community/postgres_exporter
synced 2025-04-29 14:38:04 +00:00
101 lines
2.1 KiB
Go
101 lines
2.1 KiB
Go
// Copyright 2024 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package collector
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import (
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"context"
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"database/sql"
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"log/slog"
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"github.com/prometheus/client_golang/prometheus"
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)
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const connectionsByClientSubsystem = "connections_by_client"
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func init() {
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registerCollector(connectionsByClientSubsystem, defaultEnabled, NewPGConnectionsByClientCollector)
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}
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type PGConnectionByClientCollector struct {
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log *slog.Logger
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}
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func NewPGConnectionsByClientCollector(config collectorConfig) (Collector, error) {
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return &PGConnectionByClientCollector{
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log: config.logger,
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}, nil
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}
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var (
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pgClientCountDesc = prometheus.NewDesc(
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prometheus.BuildFQName(
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namespace,
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connectionsByClientSubsystem,
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"count",
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),
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"Number of clients",
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[]string{"name"}, nil,
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)
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pgConnectionsByClientQuery = `
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SELECT
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count(*) as count,
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client_hostname
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FROM pg_stat_activity
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WHERE client_hostname is not null
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GROUP BY client_hostname;
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`
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)
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func (c PGConnectionByClientCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
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db := instance.getDB()
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rows, err := db.QueryContext(ctx,
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pgConnectionsByClientQuery,
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)
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if err != nil {
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return err
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}
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defer rows.Close()
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var count sql.NullInt64
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var name sql.NullString
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for rows.Next() {
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if err := rows.Scan(&count, &name); err != nil {
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return err
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}
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if !name.Valid {
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continue
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}
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countMetric := 0.0
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if count.Valid {
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countMetric = float64(count.Int64)
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}
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ch <- prometheus.MustNewConstMetric(
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pgClientCountDesc,
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prometheus.GaugeValue,
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countMetric,
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name.String,
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)
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}
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if err := rows.Err(); err != nil {
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return err
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}
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return nil
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}
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