Streaming Custom Audio Prompts to Genesys Cloud Interactions with Go

What You Will Build

• This tutorial builds a Go service that dynamically selects audio prompts from a CDN, plays them inside active Genesys Cloud interactions using the Media API, and tracks real-time playback state through WebSocket events.
• The implementation uses the Genesys Cloud Media API, Interaction API, and real-time WebSocket event stream.
• All code is written in Go 1.21 with the official platform-client-v2-go SDK and standard library networking packages.

Prerequisites

• OAuth client type: Confidential client (Client Credentials Grant)
• Required scopes: media:playback:write, interaction:read, user:read
• SDK version: github.com/myPureCloud/platform-client-v2-go v8.0.0 or later
• Runtime: Go 1.21+
• External dependencies: nhooyr.io/websocket, github.com/google/uuid, github.com/pkg/errors
• A CDN endpoint serving audio files (MP3, OPUS, or WAV) with valid HTTPS certificates

Authentication Setup

Genesys Cloud requires a bearer token for all API and WebSocket connections. The client credentials flow exchanges your application client ID and secret for a short-lived JWT. The token expires after thirty minutes, so your application must cache it and refresh before expiry.

package auth

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"sync"
	"time"
)

type TokenResponse struct {
	AccessToken string `json:"access_token"`
	ExpiresIn   int64  `json:"expires_in"`
}

type OAuthClient struct {
	BaseURL  string
	ClientID string
	Secret   string
	token    string
	expires  time.Time
	mu       sync.Mutex
}

func NewOAuthClient(baseURL, clientID, secret string) *OAuthClient {
	return &OAuthClient{
		BaseURL:  baseURL,
		ClientID: clientID,
		Secret:   secret,
	}
}

func (o *OAuthClient) GetToken(ctx context.Context) (string, error) {
	o.mu.Lock()
	defer o.mu.Unlock()

	if o.token != "" && time.Now().Before(o.expires.Add(-2*time.Minute)) {
		return o.token, nil
	}

	payload := fmt.Sprintf("grant_type=client_credentials&client_id=%s&client_secret=%s", o.ClientID, o.Secret)
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, o.BaseURL+"/oauth/token", nil)
	if err != nil {
		return "", fmt.Errorf("failed to create auth request: %w", err)
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.SetBasicAuth(o.ClientID, o.Secret)

	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return "", fmt.Errorf("auth request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("auth failed with status %d", resp.StatusCode)
	}

	var tokenResp TokenResponse
	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
		return "", fmt.Errorf("failed to decode token response: %w", err)
	}

	o.token = tokenResp.AccessToken
	o.expires = time.Now().Add(time.Duration(tokenResp.ExpiresIn) * time.Second)
	return o.token, nil
}

The GetToken method enforces a two-minute buffer before expiry to prevent race conditions during high-throughput playback requests. The mutex guarantees thread-safe access across concurrent Goroutines.

Implementation

Step 1: Dynamic Prompt Selection Based on User Attributes

Audio prompts must match the participant language and service tier. The Interaction API exposes participant attributes that drive prompt selection. The CDN stores assets in a predictable path structure: https://cdn.example.com/prompts/{lang}/{tier}/{prompt_key}.mp3.

package media

import (
	"context"
	"fmt"
	"strings"

	"github.com/myPureCloud/platform-client-v2-go/platformclientv2"
)

type PromptSelector struct {
	API      *platformclientv2.InteractionsApi
	CDNBase  string
}

func (s *PromptSelector) ResolvePrompt(ctx context.Context, interactionID, promptKey string) (string, error) {
	interaction, resp, err := s.API.GetInteraction(ctx, interactionID, nil)
	if err != nil {
		return "", fmt.Errorf("failed to fetch interaction: %w", err)
	}
	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("interaction API returned %d", resp.StatusCode)
	}

	participant := interaction.Participants[0]
	lang := "en"
	tier := "standard"

	if participant.Attributes != nil {
		if l, ok := participant.Attributes["language"]; ok {
			lang = strings.ToLower(l.(string))
		}
		if t, ok := participant.Attributes["service_tier"]; ok {
			tier = strings.ToLower(t.(string))
		}
	}

	// Fallback to English standard if tier is unmapped
	if tier != "standard" && tier != "premium" {
		tier = "standard"
	}

	return fmt.Sprintf("%s/%s/%s/%s.mp3", s.CDNBase, lang, tier, promptKey), nil
}

The function extracts language and service_tier from the first participant. It normalizes values and constructs a CDN URL. If attributes are missing, it defaults to English standard prompts. The API call requires the interaction:read scope.

Step 2: Construct Media Player Payloads via the Media API

The Media API accepts a POST request to /api/v2/media/play. The payload specifies the interaction ID and an array of media objects. Each object contains the CDN URL, media type, and playback options.

package media

import (
	"context"
	"fmt"
	"net/http"

	"github.com/myPureCloud/platform-client-v2-go/platformclientv2"
)

type MediaPlayer struct {
	API *platformclientv2.MediaApi
}

func (m *MediaPlayer) PlayPrompt(ctx context.Context, interactionID, audioURL string) error {
	media := platformclientv2.PlayMediaRequest{
		InteractionId: interactionID,
		Media: []platformclientv2.PlayMedia{
			{
				Url: audioURL,
				Type: platformclientv2.PtrString("audio"),
				PlaybackOptions: &platformclientv2.PlaybackOptions{
					Volume: platformclientv2.PtrFloat32(1.0),
				},
			},
		},
	}

	resp, err := m.API.PostMediaPlay(ctx, media)
	if err != nil {
		return fmt.Errorf("media play request failed: %w", err)
	}
	if resp.StatusCode != http.StatusAccepted && resp.StatusCode != http.StatusOK {
		return fmt.Errorf("media API returned %d", resp.StatusCode)
	}

	return nil
}

The PostMediaPlay SDK method serializes the struct into JSON and sends it to /api/v2/media/play. The required scope is media:playback:write. The API returns HTTP 202 Accepted when queued or HTTP 200 OK when processed immediately. Always check the response status to catch routing failures.

Step 3: Manage Audio Buffering and Playback State via WebSocket Events

Genesys Cloud streams real-time interaction updates over WebSocket. You subscribe to media.playback.state events to track buffering, playing, completed, and error states. The connection requires a JSON subscription frame followed by continuous message parsing.

package websocket

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	"github.com/nhooyr.io/websocket"
)

type PlaybackState string
const (
	StateBuffering PlaybackState = "buffering"
	StatePlaying   PlaybackState = "playing"
	StateCompleted PlaybackState = "completed"
	StateError     PlaybackState = "error"
)

type MediaEvent struct {
	Type  string        `json:"type"`
	State PlaybackState `json:"state"`
	Url   string        `json:"url"`
	Error string        `json:"error,omitempty"`
}

type WSManager struct {
	BaseURL   string
	TokenFunc func() (string, error)
	OnEvent   func(MediaEvent)
}

func (w *WSManager) Connect(ctx context.Context, interactionID string) error {
	token, err := w.TokenFunc()
	if err != nil {
		return fmt.Errorf("websocket auth failed: %w", err)
	}

	dialURL := fmt.Sprintf("%s/api/v2/interactions/events/subscribe", w.BaseURL)
	c, _, err := websocket.Dial(ctx, dialURL, &websocket.DialOptions{
		HTTPClient: &http.Client{},
		HTTPHeader: http.Header{
			"Authorization": []string{fmt.Sprintf("Bearer %s", token)},
		},
	})
	if err != nil {
		return fmt.Errorf("websocket dial failed: %w", err)
	}
	defer c.CloseNow()

	sub := map[string]interface{}{
		"action": "subscribe",
		"eventTypes": []string{"media.playback.state"},
		"filters": map[string]interface{}{
			"interactionId": interactionID,
		},
	}
	subJSON, _ := json.Marshal(sub)
	if err := c.Write(ctx, websocket.MessageText, subJSON); err != nil {
		return fmt.Errorf("subscription send failed: %w", err)
	}

	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
			_, msg, err := c.Read(ctx)
			if err != nil {
				return fmt.Errorf("websocket read failed: %w", err)
			}

			var evt MediaEvent
			if err := json.Unmarshal(msg, &evt); err != nil {
				continue
			}
			if w.OnEvent != nil {
				w.OnEvent(evt)
			}
		}
	}
}

The subscription frame filters events to a specific interaction. The read loop unmarshals each frame into MediaEvent. The OnEvent callback routes state changes to your metrics or business logic. The connection requires a valid bearer token in the Authorization header.

Step 4: Handle Codec Compatibility Checks for Different Endpoints

Different endpoints support different audio codecs. Mobile clients often prefer OPUS, while desktop softphones handle MP3 or WAV reliably. The Interaction API exposes supportedCodecs in participant media capabilities. Your service must validate the CDN asset format against this list and fallback if necessary.

package codec

import (
	"context"
	"fmt"
	"strings"

	"github.com/myPureCloud/platform-client-v2-go/platformclientv2"
)

type CodecValidator struct {
	API *platformclientv2.InteractionsApi
}

func (v *CodecValidator) ValidateAndResolve(ctx context.Context, interactionID, requestedURL string) (string, error) {
	interaction, resp, err := v.API.GetInteraction(ctx, interactionID, nil)
	if err != nil {
		return "", fmt.Errorf("failed to fetch interaction for codec check: %w", err)
	}
	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("interaction API returned %d", resp.StatusCode)
	}

	participant := interaction.Participants[0]
	supported := []string{"mp3", "opus", "wav"}
	if participant.MediaCapabilities != nil && participant.MediaCapabilities.Audio != nil {
		if codecs, ok := participant.MediaCapabilities.Audio.SupportedCodecs.(string); ok {
			supported = strings.Split(strings.ToLower(codecs), ",")
		}
	}

	ext := strings.TrimPrefix(strings.ToLower(filepath.Ext(requestedURL)), ".")
	for _, c := range supported {
		if c == ext {
			return requestedURL, nil
		}
	}

	// Fallback to OPUS if available, otherwise MP3
	fallback := "opus"
	for _, c := range supported {
		if c == "opus" || c == "mp3" {
			fallback = c
			break
		}
	}
	return strings.Replace(requestedURL, ext, fallback, 1), nil
}

The function extracts supportedCodecs from the participant media capabilities. It compares the CDN file extension against the supported list. If the requested format is unsupported, it rewrites the URL to use OPUS or MP3. This prevents silent playback failures caused by endpoint codec mismatches.

Step 5: Monitor Playback Latency and Error Rates

Latency measurement requires tracking the timestamp of the Media API request and comparing it to the completed or error WebSocket event. A thread-safe metrics collector aggregates these values for downstream monitoring systems.

package metrics

import (
	"sync"
	"time"
)

type PlaybackRecord struct {
	InteractionID string
	PromptURL     string
	StartTime     time.Time
	EndTime       time.Time
	LatencyMs     float64
	Success       bool
	ErrorMsg      string
}

type MetricsCollector struct {
	records []PlaybackRecord
	mu      sync.RWMutex
}

func NewMetricsCollector() *MetricsCollector {
	return &MetricsCollector{records: make([]PlaybackRecord, 0)}
}

func (m *MetricsCollector) Start(interactionID, url string) {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.records = append(m.records, PlaybackRecord{
		InteractionID: interactionID,
		PromptURL:     url,
		StartTime:     time.Now(),
	})
}

func (m *MetricsCollector) Complete(interactionID string, success bool, errMsg string) {
	m.mu.Lock()
	defer m.mu.Unlock()
	for i := range m.records {
		if m.records[i].InteractionID == interactionID && m.records[i].EndTime.IsZero() {
			now := time.Now()
			m.records[i].EndTime = now
			m.records[i].LatencyMs = float64(now.Sub(m.records[i].StartTime).Milliseconds())
			m.records[i].Success = success
			m.records[i].ErrorMsg = errMsg
			break
		}
	}
}

func (m *MetricsCollector) GetSummary() (avgLatency float64, errorRate float64, total int) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	if len(m.records) == 0 {
		return 0, 0, 0
	}
	var totalLatency float64
	var errors int
	for _, r := range m.records {
		if !r.EndTime.IsZero() {
			totalLatency += r.LatencyMs
			if !r.Success {
				errors++
			}
		}
	}
	return totalLatency / float64(len(m.records)), float64(errors) / float64(len(m.records)), len(m.records)
}

The Start method records the request timestamp. The Complete method calculates latency in milliseconds and marks success or failure. GetSummary returns average latency and error rate. All operations are protected by read-write locks to prevent data races during concurrent event processing.

Complete Working Example

package main

import (
	"context"
	"fmt"
	"log"
	"net/http"
	"os"
	"time"

	"github.com/myPureCloud/platform-client-v2-go/platformclientv2"
	"yourmodule/auth"
	"yourmodule/codecs"
	"yourmodule/media"
	"yourmodule/metrics"
	"yourmodule/websocket"
)

func main() {
	ctx := context.Background()

	// Configuration
	baseURL := "https://api.mypurecloud.com"
	clientID := os.Getenv("GENESYS_CLIENT_ID")
	clientSecret := os.Getenv("GENESYS_CLIENT_SECRET")
	cdnBase := "https://cdn.example.com/prompts"
	interactionID := os.Getenv("TARGET_INTERACTION_ID")

	if clientID == "" || clientSecret == "" || interactionID == "" {
		log.Fatal("Missing required environment variables")
	}

	// Initialize OAuth
	oauth := auth.NewOAuthClient(baseURL, clientID, clientSecret)

	// Initialize SDK
	config := platformclientv2.Configuration{
		BaseUrl:      baseURL,
		AccessToken:  func() (string, error) { return oauth.GetToken(ctx) },
	}
	client := platformclientv2.NewClient(config)

	// Initialize components
	selector := media.PromptSelector{API: client.InteractionsApi, CDNBase: cdnBase}
	player := media.MediaPlayer{API: client.MediaApi}
	validator := codecs.CodecValidator{API: client.InteractionsApi}
	metricsCol := metrics.NewMetricsCollector()

	// Resolve prompt
	promptURL, err := selector.ResolvePrompt(ctx, interactionID, "welcome_message")
	if err != nil {
		log.Fatalf("Prompt resolution failed: %v", err)
	}

	// Validate codec
	finalURL, err := validator.ValidateAndResolve(ctx, interactionID, promptURL)
	if err != nil {
		log.Fatalf("Codec validation failed: %v", err)
	}

	// Track metrics start
	metricsCol.Start(interactionID, finalURL)

	// Play prompt
	if err := player.PlayPrompt(ctx, interactionID, finalURL); err != nil {
		metricsCol.Complete(interactionID, false, err.Error())
		log.Fatalf("Playback request failed: %v", err)
	}

	// Subscribe to WebSocket events
	ws := websocket.WSManager{
		BaseURL:   baseURL,
		TokenFunc: func() (string, error) { return oauth.GetToken(ctx) },
		OnEvent: func(evt websocket.MediaEvent) {
			switch evt.State {
			case websocket.StateCompleted:
				metricsCol.Complete(interactionID, true, "")
				fmt.Printf("Prompt completed successfully for %s\n", interactionID)
			case websocket.StateError:
				metricsCol.Complete(interactionID, false, evt.Error)
				fmt.Printf("Playback error for %s: %s\n", interactionID, evt.Error)
			}
		},
	}

	if err := ws.Connect(ctx, interactionID); err != nil {
		log.Printf("WebSocket disconnected: %v", err)
	}

	// Print metrics after disconnect
	time.Sleep(5 * time.Second)
	avgLat, errRate, total := metricsCol.GetSummary()
	fmt.Printf("Metrics: Avg Latency %.2fms, Error Rate %.2f%%, Total %d\n", avgLat, errRate*100, total)
}

This script orchestrates authentication, prompt resolution, codec validation, playback initiation, WebSocket subscription, and metrics collection. Replace environment variables with your credentials and a valid interaction ID to run it.

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: Expired bearer token or missing Authorization header on WebSocket dial.
• Fix: Ensure the AccessToken function in the SDK configuration calls your token cache. Verify the token has not expired by checking the exp claim. Re-authenticate before retrying the request.

Error: 403 Forbidden

• Cause: OAuth token lacks media:playback:write scope.
• Fix: Update your Genesys Cloud application configuration to include media:playback:write. Revoke and regenerate tokens after scope changes.

Error: 429 Too Many Requests

• Cause: Exceeding Media API or WebSocket subscription rate limits.
• Fix: Implement exponential backoff. The SDK does not handle 429 automatically. Wrap API calls in a retry loop that checks resp.StatusCode == http.StatusTooManyRequests and sleeps for 2^n seconds before retrying.

Error: WebSocket Subscription Rejected

• Cause: Invalid JSON subscription frame or missing interactionId filter.
• Fix: Validate the subscription payload against the Genesys Cloud event schema. Ensure the action field is exactly subscribe and eventTypes contains media.playback.state.

Error: Silent Playback Failure

• Cause: Endpoint does not support the CDN audio codec.
• Fix: Enable the CodecValidator step. Log the supportedCodecs array from the interaction participant object. Fall back to OPUS or MP3 when mismatches occur.

Official References

• Media API Documentation
• Interaction WebSocket Events
• Go SDK Reference
• OAuth 2.0 Client Credentials Flow