subscriber

Documentation

Overview

Package subscriber holds logic to communicate between the external initiator service and the external endpoints it subscribes to.

Index

• type Event
• type IParser
• type ISubscriber
• type ISubscription
• type JsonManager
• type RpcSubscriber
  • func (rpc RpcSubscriber) SubscribeToEvents(channel chan<- Event, _ store.RuntimeConfig) (ISubscription, error)
  • func (rpc RpcSubscriber) Test() error
• type SubConfig
• type Type
• type WebsocketSubscriber
  • func (wss WebsocketSubscriber) SubscribeToEvents(channel chan<- Event, _ store.RuntimeConfig) (ISubscription, error)
  • func (wss WebsocketSubscriber) Test() error

Types

type Event

type Event []byte

Event is the individual event that occurs during the subscription.

type IParser

type IParser interface {
	ParseResponse(data []byte) ([]Event, bool)
}

IParser holds the interface for parsing data from the external endpoint into an array of Events based on the blockchain's parser.

type ISubscriber

type ISubscriber interface {
	// SubscribeToEvents subscribes to events using the endpoint and configuration
	// as set in ISubscriber. All events will be sent in the channel. If anything is
	// passed as a param after channel, it will not expect to receive any confirmation
	// message after opening the initial subscription.
	SubscribeToEvents(channel chan<- Event, runtimeConfig store.RuntimeConfig) (ISubscription, error)
	// Test attempts to open a connection using the endpoint and configuration
	// as set in ISubscriber. If connection is succesful, it sends GetTestJson() as a payload
	// and attempts to parse response with ParseTestResponse().
	Test() error
}

ISubscriber holds the interface for interacting with a not-yet-active subscription.

type ISubscription

type ISubscription interface {
	// Unsubscribe closes the connection to the external endpoint
	// and stops any processes related to this subscription.
	Unsubscribe()
}

ISubscription holds the interface for interacting with an active subscription.

type JsonManager

type JsonManager interface {
	// Get JSON payload to send when opening a new subscription
	GetTriggerJson() []byte
	// Parse the response returned after sending GetTriggerJson()
	ParseResponse(data []byte) ([]Event, bool)
	// Get JSON payload to send when testing a connection
	GetTestJson() []byte
	// Parse the response returned after sending GetTestJson()
	ParseTestResponse(data []byte) error
}

JsonManager holds the interface for generating blockchain specific payloads and parsing the response for the appropriate blockchain.

type RpcSubscriber

type RpcSubscriber struct {
	Endpoint string
	Interval time.Duration
	Manager  JsonManager
}

RpcSubscriber holds the configuration for a not-yet-active RPC subscription.

func (RpcSubscriber) SubscribeToEvents

func (rpc RpcSubscriber) SubscribeToEvents(channel chan<- Event, _ store.RuntimeConfig) (ISubscription, error)

func (RpcSubscriber) Test

func (rpc RpcSubscriber) Test() error

Test sends a POST request using GetTestJson() as payload, and returns the error from calling ParseTestResponse() on the response.

type SubConfig

type SubConfig struct {
	Endpoint string
}

SubConfig holds the configuration required to connect to the external endpoint.

type Type

type Type int

Type holds the connection type for the subscription

const (
	// WS are connections made over WebSocket
	WS Type = iota
	// RPC are connections made by POSTing a JSON payload
	// to the external endpoint.
	RPC
	// Client are connections encapsulated in its
	// entirety by the blockchain implementation.
	Client
	// Unknown is just a placeholder for when
	// it cannot be determined how connections
	// should be made. When this is returned,
	// it should be considered an error.
	Unknown
)

type WebsocketSubscriber

type WebsocketSubscriber struct {
	Endpoint string
	Manager  JsonManager
}

WebsocketSubscriber holds the configuration for a not-yet-active WS subscription.

func (WebsocketSubscriber) SubscribeToEvents

func (wss WebsocketSubscriber) SubscribeToEvents(channel chan<- Event, _ store.RuntimeConfig) (ISubscription, error)

func (WebsocketSubscriber) Test

func (wss WebsocketSubscriber) Test() error

Test sends a opens a WS connection to the endpoint.