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Add connection limits metrics for pg_roles and pg_database (#997)

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* Add database connection limits metrics

Signed-off-by: Jocelyn Thode <jocelyn@thode.email>

* Add roles connection limits metrics

Signed-off-by: Jocelyn Thode <jocelyn@thode.email>

* Fix copyright year

Co-authored-by: Joe Adams <github@joeadams.io>
Signed-off-by: Jocelyn Thode <jocelynthode@users.noreply.github.com>

* Fix spacing in pgDatabaseQuery

Co-authored-by: Joe Adams <github@joeadams.io>
Signed-off-by: Jocelyn Thode <jocelynthode@users.noreply.github.com>

* Fix case on pgRolesConnectionLimitsQuery

Co-authored-by: Joe Adams <github@joeadams.io>
Signed-off-by: Jocelyn Thode <jocelynthode@users.noreply.github.com>

* Do not add roleMetrics when row is not valid

Signed-off-by: Jocelyn Thode <jocelyn@thode.email>

---------

Signed-off-by: Jocelyn Thode <jocelyn@thode.email>
Signed-off-by: Jocelyn Thode <jocelynthode@users.noreply.github.com>
Co-authored-by: Joe Adams <github@joeadams.io>
This commit is contained in:
Jocelyn Thode 2024-02-22 03:10:17 +01:00 committed by GitHub
parent f98834a678
commit 8f39f5b114
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
4 changed files with 181 additions and 9 deletions
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31
collector/pg_database.go
View File

@ -53,12 +53,21 @@ var (
"Disk space used by the database",
[]string{"datname"}, nil,
)
pgDatabaseConnectionLimitsDesc = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
databaseSubsystem,
"connection_limit",
),
"Connection limit set for the database",
[]string{"datname"}, nil,
)
pgDatabaseQuery = "SELECT pg_database.datname FROM pg_database;"
pgDatabaseQuery = "SELECT pg_database.datname, pg_database.datconnlimit FROM pg_database;"
pgDatabaseSizeQuery = "SELECT pg_database_size($1)"
)
// Update implements Collector and exposes database size.
// Update implements Collector and exposes database size and connection limits.
// It is called by the Prometheus registry when collecting metrics.
// The list of databases is retrieved from pg_database and filtered
// by the excludeDatabase config parameter. The tradeoff here is that
@ -81,21 +90,32 @@ func (c PGDatabaseCollector) Update(ctx context.Context, instance *instance, ch
for rows.Next() {
var datname sql.NullString
if err := rows.Scan(&datname); err != nil {
var connLimit sql.NullInt64
if err := rows.Scan(&datname, &connLimit); err != nil {
return err
}
if !datname.Valid {
continue
}
database := datname.String
// Ignore excluded databases
// Filtering is done here instead of in the query to avoid
// a complicated NOT IN query with a variable number of parameters
if sliceContains(c.excludedDatabases, datname.String) {
if sliceContains(c.excludedDatabases, database) {
continue
}
databases = append(databases, datname.String)
databases = append(databases, database)
connLimitMetric := 0.0
if connLimit.Valid {
connLimitMetric = float64(connLimit.Int64)
}
ch <- prometheus.MustNewConstMetric(
pgDatabaseConnectionLimitsDesc,
prometheus.GaugeValue, connLimitMetric, database,
)
}
// Query the size of the databases
@ -114,6 +134,7 @@ func (c PGDatabaseCollector) Update(ctx context.Context, instance *instance, ch
pgDatabaseSizeDesc,
prometheus.GaugeValue, sizeMetric, datname,
)
}
return rows.Err()
}

10
collector/pg_database_test.go
View File

@ -31,8 +31,8 @@ func TestPGDatabaseCollector(t *testing.T) {
inst := &instance{db: db}
mock.ExpectQuery(sanitizeQuery(pgDatabaseQuery)).WillReturnRows(sqlmock.NewRows([]string{"datname"}).
AddRow("postgres"))
mock.ExpectQuery(sanitizeQuery(pgDatabaseQuery)).WillReturnRows(sqlmock.NewRows([]string{"datname", "datconnlimit"}).
AddRow("postgres", 15))
mock.ExpectQuery(sanitizeQuery(pgDatabaseSizeQuery)).WithArgs("postgres").WillReturnRows(sqlmock.NewRows([]string{"pg_database_size"}).
AddRow(1024))
@ -47,6 +47,7 @@ func TestPGDatabaseCollector(t *testing.T) {
}()
expected := []MetricResult{
{labels: labelMap{"datname": "postgres"}, value: 15, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"datname": "postgres"}, value: 1024, metricType: dto.MetricType_GAUGE},
}
convey.Convey("Metrics comparison", t, func() {
@ -71,8 +72,8 @@ func TestPGDatabaseCollectorNullMetric(t *testing.T) {
inst := &instance{db: db}
mock.ExpectQuery(sanitizeQuery(pgDatabaseQuery)).WillReturnRows(sqlmock.NewRows([]string{"datname"}).
AddRow("postgres"))
mock.ExpectQuery(sanitizeQuery(pgDatabaseQuery)).WillReturnRows(sqlmock.NewRows([]string{"datname", "datconnlimit"}).
AddRow("postgres", nil))
mock.ExpectQuery(sanitizeQuery(pgDatabaseSizeQuery)).WithArgs("postgres").WillReturnRows(sqlmock.NewRows([]string{"pg_database_size"}).
AddRow(nil))
@ -88,6 +89,7 @@ func TestPGDatabaseCollectorNullMetric(t *testing.T) {
expected := []MetricResult{
{labels: labelMap{"datname": "postgres"}, value: 0, metricType: dto.MetricType_GAUGE},
{labels: labelMap{"datname": "postgres"}, value: 0, metricType: dto.MetricType_GAUGE},
}
convey.Convey("Metrics comparison", t, func() {
for _, expect := range expected {

91
collector/pg_roles.go Normal file
View File

@ -0,0 +1,91 @@
// Copyright 2024 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/go-kit/log"
"github.com/prometheus/client_golang/prometheus"
)
const rolesSubsystem = "roles"
func init() {
registerCollector(rolesSubsystem, defaultEnabled, NewPGRolesCollector)
}
type PGRolesCollector struct {
log log.Logger
}
func NewPGRolesCollector(config collectorConfig) (Collector, error) {
return &PGRolesCollector{
log: config.logger,
}, nil
}
var (
pgRolesConnectionLimitsDesc = prometheus.NewDesc(
prometheus.BuildFQName(
namespace,
rolesSubsystem,
"connection_limit",
),
"Connection limit set for the role",
[]string{"rolname"}, nil,
)
pgRolesConnectionLimitsQuery = "SELECT pg_roles.rolname, pg_roles.rolconnlimit FROM pg_roles"
)
// Update implements Collector and exposes roles connection limits.
// It is called by the Prometheus registry when collecting metrics.
func (c PGRolesCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
db := instance.getDB()
// Query the list of databases
rows, err := db.QueryContext(ctx,
pgRolesConnectionLimitsQuery,
)
if err != nil {
return err
}
defer rows.Close()
for rows.Next() {
var rolname sql.NullString
var connLimit sql.NullInt64
if err := rows.Scan(&rolname, &connLimit); err != nil {
return err
}
if !rolname.Valid {
continue
}
rolnameLabel := rolname.String
if !connLimit.Valid {
continue
}
connLimitMetric := float64(connLimit.Int64)
ch <- prometheus.MustNewConstMetric(
pgRolesConnectionLimitsDesc,
prometheus.GaugeValue, connLimitMetric, rolnameLabel,
)
}
return rows.Err()
}

58
collector/pg_roles_test.go Normal file
View File

@ -0,0 +1,58 @@
// 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 TestPGRolesCollector(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}
mock.ExpectQuery(sanitizeQuery(pgRolesConnectionLimitsQuery)).WillReturnRows(sqlmock.NewRows([]string{"rolname", "rolconnlimit"}).
AddRow("postgres", 15))
ch := make(chan prometheus.Metric)
go func() {
defer close(ch)
c := PGRolesCollector{}
if err := c.Update(context.Background(), inst, ch); err != nil {
t.Errorf("Error calling PGRolesCollector.Update: %s", err)
}
}()
expected := []MetricResult{
{labels: labelMap{"rolname": "postgres"}, value: 15, metricType: dto.MetricType_GAUGE},
}
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)
}
}