Documentation
¶
Overview ¶
Copyright (c) 2021 Nutanix, Inc.
Package transport provides a Publish/Subscribe interface for publishing data from streams to data pipelines or subscribing to data from the data pipelines to publish to the streams.
transport package exposes two interfaces:
type Client interface {
Publish(channel string, msg Message) error
Subscribe(channel string, callback MessageHandler) (Subscription, error)
}
and
type Subscription interface {
Unsubscribe() error
Channel() string
}
A `Client` can be created by calling the `NewTransportClient` function:
client, err := NewTransportClient()
Note, the client created by the `NewTransportClient` function is a singleton. Repeated calls to the function will return the same client.
In order to publish data into the transport, we need to create a Message object:
msg := &Message{
Payload: []byte("example")
}
Once, the client has been created, it can be used to Publish data from streams into the transport channel:
client.Publish(stream.GetTransportChannel(), msg)
In order to create a subscription, the client needs to provide a callback with the MessageHandler signature. This callback gets called with a message as parameter each time a new message is received on the subscribed channel.
func msgHandler (msg *Message) {
// Do stuff
}
Subsequently, a subscription can be created for subscribing to the data from the transport channel:
sub, err := client.Subscribe(stream.GetTransportChannel(), msgHandler)
A subscription also exposes the channel it is subscribed to via the `Channel` method:
channel := sub.Channel()
When a subscription is no longer needed, it can be unsubscribed by calling the `Unsubscribe` method:
sub.Unsubscribe()
Copyright (c) 2021 Nutanix, Inc.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Client ¶
type Client interface {
// Publish publishes the message onto the provided channel
Publish(channel string, msg Message) error
// Subscribe subscribes all future messages on the channel and registers a callback
Subscribe(channel string, callback MessageHandler) (Subscription, error)
}
Client describes the publish / subscribe interface of the transport client
func NewTransportClient ¶
NewTransportClient returns a client for publishing and subscribing to datastreams from data pipelines
type Message ¶
type Message struct {
Payload []byte `json:"payload"`
}
Message defines the data structure of the messages conveyed by the transport
type MessageHandler ¶
type MessageHandler func(msg *Message)
MessageHandler defines the function signature for the callback function in a Subscribe call
type Subscription ¶
type Subscription interface {
// Unsubscribe unsubscribes the connection
Unsubscribe() error
// Channel returns the channel the subscription belongs to
Channel() string
}
Subscription describes the interface of the subscription object
Source Files