This implementation is similar to AMQP notifications: * Notifications are published on a single topic as a JSON feed * Topic is configurable, as is the QoS. Uses the paho.mqtt.golang library for the mqtt connection, and supports connections over tcp and websockets, with optional secure tls support. * Additionally the minio server configuration has been bumped up so mqtt configuration can be added. * Configuration migration code is added with tests. MQTT is an ISO standard M2M/IoT messaging protocol and was originally designed for applications for limited bandwidth networks. Today it's use is growing in the IoT space.
62 lines
1.4 KiB
Go
62 lines
1.4 KiB
Go
package packets
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import (
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"bytes"
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"fmt"
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"io"
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)
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//SubscribePacket is an internal representation of the fields of the
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//Subscribe MQTT packet
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type SubscribePacket struct {
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FixedHeader
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MessageID uint16
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Topics []string
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Qoss []byte
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}
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func (s *SubscribePacket) String() string {
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str := fmt.Sprintf("%s", s.FixedHeader)
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str += " "
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str += fmt.Sprintf("MessageID: %d topics: %s", s.MessageID, s.Topics)
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return str
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}
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func (s *SubscribePacket) Write(w io.Writer) error {
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var body bytes.Buffer
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var err error
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body.Write(encodeUint16(s.MessageID))
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for i, topic := range s.Topics {
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body.Write(encodeString(topic))
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body.WriteByte(s.Qoss[i])
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}
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s.FixedHeader.RemainingLength = body.Len()
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packet := s.FixedHeader.pack()
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packet.Write(body.Bytes())
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_, err = packet.WriteTo(w)
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return err
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}
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//Unpack decodes the details of a ControlPacket after the fixed
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//header has been read
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func (s *SubscribePacket) Unpack(b io.Reader) error {
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s.MessageID = decodeUint16(b)
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payloadLength := s.FixedHeader.RemainingLength - 2
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for payloadLength > 0 {
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topic := decodeString(b)
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s.Topics = append(s.Topics, topic)
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qos := decodeByte(b)
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s.Qoss = append(s.Qoss, qos)
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payloadLength -= 2 + len(topic) + 1 //2 bytes of string length, plus string, plus 1 byte for Qos
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}
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return nil
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}
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//Details returns a Details struct containing the Qos and
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//MessageID of this ControlPacket
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func (s *SubscribePacket) Details() Details {
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return Details{Qos: 1, MessageID: s.MessageID}
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}
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