PostgreSQL

/*

** Zabbix

** Copyright 2001-2024 Zabbix SIA

**

** 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 plugin

​

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)

    }

​

    return connectionsJSON, nil

}