appsync-event-client-go

Appsync Event Client

Appsync event client is a go websocket client library for connecting with the AWS Appsync Event API.

Install

go get github.com/brokgo/appsync-event-client-go/appsync

Quick Start

Publish

The following examples shows how to publish an event to the Appsync Event using an api key. Replace httpEndpoint, realtimeEndpoint, and apiKey with your own values.

import (
	"context"
	"encoding/json"
	"fmt"

	"github.com/brokgo/appsync-event-client-go/appsync"
)

// Appsync endpoints
httpEndpoint := "<ID>.appsync-api.<region>.amazonaws.com"
realtimeEndpoint := "<ID>.appsync-realtime-api.<region>.amazonaws.com"

// Authentication method
apiKey := "ab-cdefghijklmnopqrstuvwxyz"
config := appsync.NewAPIKeyConfig(httpEndpoint, realtimeEndpoint, apiKey)

// Client
ctx := context.Background()
client, err := appsync.DialWebSocketConfig(ctx, config)
if err != nil {
    panic(err)
}

// JSON event(s) to publish
eventABytes, err := json.Marshal(struct {
    A string `json:"a"`
}{
    A: "123",
})
if err != nil {
    panic(err)
}
eventBBytes, err := json.Marshal(struct {
    B string `json:"b"`
}{
    B: "123",
})
if err != nil {
    panic(err)
}
events := []string{string(eventABytes), string(eventBBytes)}

// Publish
channel := "/default/example"
successIndicies, err := client.Publish(ctx, channel, events)
if err != nil {
    panic(err)
}

// Results
fmt.Println(successIndicies)

// Close
err = client.Close()
if err != nil {
    panic(err)
}

Subscription

The following examples shows how to subscribe to an Appsync Event channel using an api key. Replace httpEndpoint, realtimeEndpoint, and apiKey with your own values.

import (
	"context"
	"fmt"

	"github.com/brokgo/appsync-event-client-go/appsync"
    "github.com/brokgo/appsync-event-client-go/appsync/message"
)

// Appsync endpoints
httpEndpoint := "<ID>.appsync-api.<region>.amazonaws.com"
realtimeEndpoint := "<ID>.appsync-realtime-api.<region>.amazonaws.com"

// Authentication method
apiKey := "ab-cdefghijklmnopqrstuvwxyz"
config := appsync.NewAPIKeyConfig(httpEndpoint, realtimeEndpoint, apiKey)

// Client
ctx := context.Background()
client, err := appsync.DialWebSocketConfig(ctx, config)
if err != nil {
    panic(err)
}

// Subscribe
channel := "/default/example"
msgC := make(chan *message.SubscriptionMessage)
err = client.Subscribe(ctx, channel, msgC)
if err != nil {
    panic(err)
}

// Result
msg, ok := <-msgC
if !ok {
    panic(client.Err)
}
fmt.Println(msg.Event)

// Close
err = client.Close()
if err != nil {
    panic(err)
}

Documentation

See documentation to see additional examples and the API reference for the library.

Websocket Appsync Event API

Image from https://docs.aws.amazon.com/appsync/latest/eventapi/event-api-websocket-protocol.html.