types

Documentation

Index

• Constants
• type HostInfo
  • func (info *HostInfo) GetHostURL() string
  • func (info *HostInfo) IsHostInfoEmpty() bool
• type MessageBusConfig
• type MessageEnvelope
  • func NewMessageEnvelope(payload []byte, ctx context.Context) MessageEnvelope
  • func NewMessageEnvelopeForRequest(payload []byte, queryParams map[string]string) MessageEnvelope
  • func NewMessageEnvelopeForResponse(payload []byte, requestId string, correlationId string, contentType string) (MessageEnvelope, error)
  • func NewMessageEnvelopeFromJSON(message []byte) (MessageEnvelope, error)
  • func NewMessageEnvelopeWithError(requestId string, errorMessage string) MessageEnvelope
• type TopicChannel

Constants

const (
	ApiVersion      = "v2"
	CorrelationID   = "X-Correlation-ID"
	ContentType     = "Content-Type"
	ContentTypeJSON = "application/json"
	ContentTypeText = "text/plain"
)

Types

type HostInfo

type HostInfo struct {
	// Host is the hostname or IP address of the messaging broker, if applicable.
	Host string
	// Port defines the port on which to access the message queue.
	Port int
	// Protocol indicates the protocol to use when accessing the message queue.
	Protocol string
}

HostInfo is the URL information of the host as the following scheme: <Protocol>://<Host>:<Port>

func (*HostInfo) GetHostURL

func (info *HostInfo) GetHostURL() string

GetHostURL returns the complete URL for the host-info configuration

func (*HostInfo) IsHostInfoEmpty

func (info *HostInfo) IsHostInfoEmpty() bool

IsHostInfoEmpty returns whether the host-info has been initialized or not

type MessageBusConfig

type MessageBusConfig struct {
	// PublishHost contains the connection information for a publishing on 0mq
	PublishHost HostInfo
	// SubscribeHost contains the connection information for a subscribing on 0mq
	SubscribeHost HostInfo
	// Type indicates the message queue platform being used. eg. "zero" for 0mq
	Type string
	// Optional contains all other properties of message bus that is specific to
	// certain concrete implementation like MQTT's QoS, for example
	Optional map[string]string
}

MessageBusConfig defines the messaging information need to connect to the message bus in a publish-subscribe pattern

type MessageEnvelope

type MessageEnvelope struct {
	// ReceivedTopic is the topic that the message was received on.
	ReceivedTopic string
	// CorrelationID is an object id to identify the envelope.
	CorrelationID string
	// ApiVersion shows the API version in message envelope.
	ApiVersion string
	// RequestID is an object id to identify the request.
	RequestID string
	// ErrorCode provides the indication of error. '0' indicates no error, '1' indicates error.
	// Additional codes may be added in the future. If non-0, the payload will contain the error.
	ErrorCode int
	// Payload is byte representation of the data being transferred.
	Payload []byte
	// ContentType is the marshaled type of payload, i.e. application/json, application/xml, application/cbor, etc
	ContentType string
	// QueryParams is optionally provided key/value pairs.
	QueryParams map[string]string
}

MessageEnvelope is the data structure for messages. It wraps the generic message payload with attributes.

func NewMessageEnvelope

func NewMessageEnvelope(payload []byte, ctx context.Context) MessageEnvelope

NewMessageEnvelope creates a new MessageEnvelope for the specified payload with attributes from the specified context

func NewMessageEnvelopeForRequest

func NewMessageEnvelopeForRequest(payload []byte, queryParams map[string]string) MessageEnvelope

NewMessageEnvelopeForRequest creates a new MessageEnvelope for sending request to EdgeX via internal MessageBus to target Device Service. Used when request is from internal App Service via command client.

func NewMessageEnvelopeForResponse

func NewMessageEnvelopeForResponse(payload []byte, requestId string, correlationId string, contentType string) (MessageEnvelope, error)

NewMessageEnvelopeForResponse creates a new MessageEnvelope for sending response from Device Service back to Core Command.

func NewMessageEnvelopeFromJSON

func NewMessageEnvelopeFromJSON(message []byte) (MessageEnvelope, error)

NewMessageEnvelopeFromJSON creates a new MessageEnvelope by decoding the message payload received from external MQTT in order to send request via internal MessageBus.

func NewMessageEnvelopeWithError

func NewMessageEnvelopeWithError(requestId string, errorMessage string) MessageEnvelope

NewMessageEnvelopeWithError creates a new MessageEnvelope with ErrorCode set to 1 indicating there's error and the payload contains message string about the error.

type TopicChannel

type TopicChannel struct {
	// Topic for subscriber to filter on if any
	Topic string
	// Messages is the returned message channel for the subscriber
	Messages chan MessageEnvelope
}

TopicChannel is the data structure for subscriber