Zabbix

/*

** Zabbix

** Copyright (C) 2001-2022 Zabbix SIA

**

** This program is free software; you can redistribute it and/or modify

** it under the terms of the GNU General Public License as published by

** the Free Software Foundation; either version 2 of the License, or

** (at your option) any later version.

**

** This program is distributed in the hope that it will be useful,

** but WITHOUT ANY WARRANTY; without even the implied warranty of

** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

** GNU General Public License for more details.

**

** You should have received a copy of the GNU General Public License

** along with this program; if not, write to the Free Software

** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

**/

​

package postgres

​

import (

    "context"

    "errors"

​

    "git.zabbix.com/ap/plugin-support/zbxerr"

    "github.com/jackc/pgx/v4"

)

​

// connectionsHandler executes select from pg_stat_activity command and returns JSON if all is OK or nil otherwise.

func connectionsHandler(ctx context.Context, conn PostgresClient,

    _ string, _ map[string]string, _ ...string) (interface{}, error) {

    var connectionsJSON string

​

    query := `SELECT row_to_json(T)

    FROM (

        SELECT

            sum(CASE WHEN state = 'active' THEN 1 ELSE 0 END) AS active,

            sum(CASE WHEN state = 'idle' THEN 1 ELSE 0 END) AS idle,

            sum(CASE WHEN state = 'idle in transaction' THEN 1 ELSE 0 END) AS idle_in_transaction,

            sum(CASE WHEN state = 'idle in transaction (aborted)' THEN 1 ELSE 0 END) AS idle_in_transaction_aborted,

            sum(CASE WHEN state = 'fastpath function call' THEN 1 ELSE 0 END) AS fastpath_function_call,

            sum(CASE WHEN state = 'disabled' THEN 1 ELSE 0 END) AS disabled,

            count(*) AS total,

            count(*)*100/(SELECT current_setting('max_connections')::int) AS total_pct,

            sum(CASE WHEN wait_event IS NOT NULL THEN 1 ELSE 0 END) AS waiting,

            (SELECT count(*) FROM pg_prepared_xacts) AS prepared

        FROM pg_stat_activity WHERE datid IS NOT NULL AND state IS NOT NULL) T;`

​

    row, err := conn.QueryRow(ctx, query)

    if err != nil {

        return nil, zbxerr.ErrorCannotFetchData.Wrap(err)

    }

​

    err = row.Scan(&connectionsJSON)

    if err != nil {

        if errors.Is(err, pgx.ErrNoRows) {

            return nil, zbxerr.ErrorEmptyResult.Wrap(err)

        }

​

        return nil, zbxerr.ErrorCannotFetchData.Wrap(err)

    }

​