8293f546af
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.
80 lines
1.9 KiB
Go
80 lines
1.9 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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//PublishPacket is an internal representation of the fields of the
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//Publish MQTT packet
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type PublishPacket struct {
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FixedHeader
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TopicName string
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MessageID uint16
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Payload []byte
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}
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func (p *PublishPacket) String() string {
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str := fmt.Sprintf("%s", p.FixedHeader)
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str += " "
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str += fmt.Sprintf("topicName: %s MessageID: %d", p.TopicName, p.MessageID)
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str += " "
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str += fmt.Sprintf("payload: %s", string(p.Payload))
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return str
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}
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func (p *PublishPacket) 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(encodeString(p.TopicName))
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if p.Qos > 0 {
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body.Write(encodeUint16(p.MessageID))
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}
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p.FixedHeader.RemainingLength = body.Len() + len(p.Payload)
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packet := p.FixedHeader.pack()
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packet.Write(body.Bytes())
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packet.Write(p.Payload)
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_, err = w.Write(packet.Bytes())
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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 (p *PublishPacket) Unpack(b io.Reader) error {
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var payloadLength = p.FixedHeader.RemainingLength
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p.TopicName = decodeString(b)
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if p.Qos > 0 {
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p.MessageID = decodeUint16(b)
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payloadLength -= len(p.TopicName) + 4
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} else {
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payloadLength -= len(p.TopicName) + 2
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}
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if payloadLength < 0 {
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return fmt.Errorf("Error upacking publish, payload length < 0")
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}
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p.Payload = make([]byte, payloadLength)
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_, err := b.Read(p.Payload)
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return err
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}
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//Copy creates a new PublishPacket with the same topic and payload
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//but an empty fixed header, useful for when you want to deliver
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//a message with different properties such as Qos but the same
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//content
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func (p *PublishPacket) Copy() *PublishPacket {
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newP := NewControlPacket(Publish).(*PublishPacket)
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newP.TopicName = p.TopicName
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newP.Payload = p.Payload
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return newP
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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 (p *PublishPacket) Details() Details {
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return Details{Qos: p.Qos, MessageID: p.MessageID}
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}
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