Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

plugins/common/mqtt/mqtt.go

@@ -0,0 +1,95 @@
+package mqtt
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"strings"
+
+	paho "github.com/eclipse/paho.mqtt.golang"
+
+	"github.com/influxdata/telegraf/config"
+	"github.com/influxdata/telegraf/plugins/common/tls"
+)
+
+// mqtt v5-specific publish properties.
+// See https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901109
+type PublishProperties struct {
+	ContentType    string            `toml:"content_type"`
+	ResponseTopic  string            `toml:"response_topic"`
+	MessageExpiry  config.Duration   `toml:"message_expiry"`
+	TopicAlias     *uint16           `toml:"topic_alias"`
+	UserProperties map[string]string `toml:"user_properties"`
+}
+
+type MqttConfig struct {
+	Servers             []string           `toml:"servers"`
+	Protocol            string             `toml:"protocol"`
+	Username            config.Secret      `toml:"username"`
+	Password            config.Secret      `toml:"password"`
+	Timeout             config.Duration    `toml:"timeout"`
+	ConnectionTimeout   config.Duration    `toml:"connection_timeout"`
+	QoS                 int                `toml:"qos"`
+	ClientID            string             `toml:"client_id"`
+	Retain              bool               `toml:"retain"`
+	KeepAlive           int64              `toml:"keep_alive"`
+	PersistentSession   bool               `toml:"persistent_session"`
+	PublishPropertiesV5 *PublishProperties `toml:"v5"`
+	ClientTrace         bool               `toml:"client_trace"`
+
+	tls.ClientConfig
+
+	AutoReconnect    bool        `toml:"-"`
+	OnConnectionLost func(error) `toml:"-"`
+}
+
+// Client is a protocol neutral MQTT client for connecting,
+// disconnecting, and publishing data to a topic.
+// The protocol specific clients must implement this interface
+type Client interface {
+	Connect() (bool, error)
+	Publish(topic string, data []byte) error
+	SubscribeMultiple(filters map[string]byte, callback paho.MessageHandler) error
+	AddRoute(topic string, callback paho.MessageHandler)
+	Close() error
+}
+
+func NewClient(cfg *MqttConfig) (Client, error) {
+	if len(cfg.Servers) == 0 {
+		return nil, errors.New("no servers specified")
+	}
+
+	if cfg.PersistentSession && cfg.ClientID == "" {
+		return nil, errors.New("persistent_session requires client_id")
+	}
+
+	if cfg.QoS > 2 || cfg.QoS < 0 {
+		return nil, fmt.Errorf("invalid QoS value %d; must be 0, 1 or 2", cfg.QoS)
+	}
+
+	switch cfg.Protocol {
+	case "", "3.1.1":
+		return NewMQTTv311Client(cfg)
+	case "5":
+		return NewMQTTv5Client(cfg)
+	}
+	return nil, fmt.Errorf("unsupported protocol %q: must be \"3.1.1\" or \"5\"", cfg.Protocol)
+}
+
+func parseServers(servers []string) ([]*url.URL, error) {
+	urls := make([]*url.URL, 0, len(servers))
+	for _, svr := range servers {
+		// Preserve support for host:port style servers; deprecated in Telegraf 1.4.4
+		if !strings.Contains(svr, "://") {
+			urls = append(urls, &url.URL{Scheme: "tcp", Host: svr})
+			continue
+		}
+
+		u, err := url.Parse(svr)
+		if err != nil {
+			return nil, err
+		}
+		urls = append(urls, u)
+	}
+	return urls, nil
+}