Zabbix

/*

** Zabbix

** Copyright (C) 2001-2025 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 redis

​

import (

    "context"

    "errors"

    "sync"

    "time"

​

    "github.com/mediocregopher/radix/v3"

    "golang.zabbix.com/sdk/log"

    "golang.zabbix.com/sdk/uri"

    "golang.zabbix.com/sdk/zbxerr"

)

​

const hkInterval = 10

​

var errMasterDown = errors.New("MASTERDOWN Link with MASTER is down and slave-serve-stale-data is set to 'no'.")

​

type redisClient interface {

    Query(cmd radix.CmdAction) error

}

​

type RedisConn struct {

    client         radix.Client

    lastTimeAccess time.Time

}

​

// Query wraps the radix.Client.Do function.

func (r *RedisConn) Query(cmd radix.CmdAction) error {

    return r.client.Do(cmd)

}

​

// updateAccessTime updates the last time a connection was accessed.

func (r *RedisConn) updateAccessTime() {

    r.lastTimeAccess = time.Now()

}

​

// ConnManager is thread-safe structure for manage connections.

type ConnManager struct {

    sync.Mutex

    connMutex   sync.Mutex

    connections map[uri.URI]*RedisConn

    keepAlive   time.Duration

    timeout     time.Duration

    Destroy     context.CancelFunc

}

​

// NewConnManager initializes ConnManager structure and runs Go Routine that watches for unused connections.

func NewConnManager(keepAlive, timeout, hkInterval time.Duration) *ConnManager {

    ctx, cancel := context.WithCancel(context.Background())

​

    connMgr := &ConnManager{

        connections: make(map[uri.URI]*RedisConn),

        keepAlive:   keepAlive,

        timeout:     timeout,

        Destroy:     cancel, // Destroy stops originated goroutines and close connections.

    }

​

    go connMgr.housekeeper(ctx, hkInterval)

​

    return connMgr

}

​

// closeUnused closes each connection that has not been accessed at least within the keepalive interval.

func (c *ConnManager) closeUnused() {

    c.connMutex.Lock()

    defer c.connMutex.Unlock()

​

    for uri, conn := range c.connections {

        if time.Since(conn.lastTimeAccess) > c.keepAlive {

            if err := conn.client.Close(); err == nil {

                delete(c.connections, uri)