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 external

​

import (

    "encoding/json"

    "net"

    "sync"

    "sync/atomic"

    "time"

​

    "golang.zabbix.com/sdk/errs"

    "golang.zabbix.com/sdk/log"

    "golang.zabbix.com/sdk/plugin/comms"

)

​

var (

    // ErrBrokerClosed is returned when a request is made on a closed broker.

    ErrBrokerClosed = errs.New("broker closed")

    // ErrBrokerTimeout is returned when a request sent by broker does not

    // receive a response within timeout.

    ErrBrokerTimeout = errs.New("broker timeout")

)

​

// pluginBroker handles communication with a single plugin.

type pluginBroker struct {

    timeout   time.Duration

    conn      net.Conn

    requestID atomic.Uint32

​

    // map of requestID to requests awaiting response from plugin

    requests      map[uint32]*requestWithResponse

    requestsMutex sync.Mutex

​

    // channel to handle agent to plugin requests

    // can have only *request and *requestWithResponse types

    tx chan any

​

    logr log.Logger

}

​

// describes a one directional (agent to plugin) request. err chan is closed

// when request is sent out.

type request struct {

    id  uint32

    in  any

    err chan error

}

​

// requestWithResponse describes a request that expects a response from the plugin.

// out, err chan are closed when response or error is received.

type requestWithResponse struct {

    id  uint32

    in  any

    out chan []byte

    err chan error

}

​

func newBroker(

    conn net.Conn, timeout time.Duration, logr log.Logger,

) *pluginBroker {

    pb := &pluginBroker{

        timeout:  timeout,

        conn:     conn,

        requests: make(map[uint32]*requestWithResponse),

        tx:       make(chan any),

        logr:     logr,

    }

​

    go pb.reader()

    go pb.writer()

​

    return pb

}