Download and Convert Genesys Cloud Conversation Audio to Mono WAV with Go Worker Pools

What You Will Build

• This service downloads conversation audio files from Genesys Cloud CX and converts stereo streams to mono WAV format on demand.
• The implementation uses the Genesys Cloud Media API endpoint /api/v2/media/conversations/{conversationId}/audio.
• The code is written in Go and utilizes a concurrent worker pool pattern for parallel processing.

Prerequisites

• OAuth 2.0 Client Credentials grant type with the media:audio:read scope.
• Genesys Cloud API v2.
• Go 1.21 or higher.
• External dependencies: github.com/go-audio/wav and github.com/go-audio/audio for WAV header parsing and PCM manipulation.

Authentication Setup

Genesys Cloud uses OAuth 2.0 for API authentication. The client credentials flow exchanges your client ID and secret for a bearer token. You must request the media:audio:read scope to access conversation audio.

HTTP Request Cycle

POST https://api.mypurecloud.com/api/v2/oauth/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Authorization: Basic base64(client_id:client_secret)
Host: api.mypurecloud.com

grant_type=client_credentials&scope=media:audio:read

HTTP Response

{
  "access_token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...",
  "token_type": "bearer",
  "expires_in": 1200,
  "scope": "media:audio:read"
}

The following Go function implements token retrieval with in-memory caching and automatic expiration tracking. This prevents unnecessary token refresh calls during batch processing.

package main

import (
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"sync"
	"time"
)

type TokenResponse struct {
	AccessToken string `json:"access_token"`
	ExpiresIn   int    `json:"expires_in"`
	Scope       string `json:"scope"`
}

type TokenManager struct {
	mu        sync.Mutex
	token     string
	expiresAt time.Time
	clientID  string
	secret    string
	orgURL    string
}

func NewTokenManager(clientID, secret, orgURL string) *TokenManager {
	return &TokenManager{
		clientID: clientID,
		secret:   secret,
		orgURL:   orgURL,
	}
}

func (tm *TokenManager) GetToken() (string, error) {
	tm.mu.Lock()
	defer tm.mu.Unlock()

	if tm.token != "" && time.Now().Before(tm.expiresAt.Add(-30*time.Second)) {
		return tm.token, nil
	}

	resp, err := http.PostForm(fmt.Sprintf("%s/api/v2/oauth/token", tm.orgURL), url.Values{
		"grant_type": {"client_credentials"},
		"scope":      {"media:audio:read"},
	})
	if err != nil {
		return "", fmt.Errorf("oauth request failed: %w", err)
	}
	defer resp.Body.Close()

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

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

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

Implementation

Step 1: Configure HTTP Client with Retry Logic for Rate Limits

The Genesys Cloud Media API enforces strict rate limits. A 429 Too Many Requests response requires exponential backoff with jitter. The following client configuration handles retries automatically and follows 302 redirects to the underlying S3 presigned URLs.

package main

import (
	"fmt"
	"math/rand"
	"net/http"
	"time"
)

func NewMediaHTTPClient() *http.Client {
	return &http.Client{
		Timeout: 60 * time.Second,
		Transport: &http.Transport{
			MaxIdleConns:        100,
			MaxIdleConnsPerHost: 100,
			IdleConnTimeout:     90 * time.Second,
		},
		CheckRedirect: func(req *http.Request, via []*http.Request) error {
			// Allow redirects to S3 presigned URLs
			return nil
		},
	}
}

func doWithRetry(client *http.Client, req *http.Request, maxRetries int) (*http.Response, error) {
	var resp *http.Response
	var err error

	for attempt := 0; attempt <= maxRetries; attempt++ {
		resp, err = client.Do(req)
		if err != nil {
			return nil, fmt.Errorf("http request failed: %w", err)
		}

		if resp.StatusCode == http.StatusTooManyRequests {
			resp.Body.Close()
			if attempt == maxRetries {
				return nil, fmt.Errorf("exceeded max retries for 429 rate limit")
			}
			// Exponential backoff with jitter
			baseDelay := time.Duration(1<<uint(attempt)) * time.Second
			jitter := time.Duration(rand.Intn(1000)) * time.Millisecond
			time.Sleep(baseDelay + jitter)
			continue
		}

		if resp.StatusCode >= 500 {
			resp.Body.Close()
			if attempt == maxRetries {
				return nil, fmt.Errorf("server error %d after %d retries", resp.StatusCode, maxRetries)
			}
			time.Sleep(time.Duration(1<<uint(attempt)) * time.Second)
			continue
		}

		return resp, nil
	}
	return resp, err
}

Step 2: Build the Concurrent Worker Pool

Processing hundreds of conversations sequentially creates unnecessary latency. A worker pool distributes download and conversion tasks across a fixed number of goroutines. The pool uses buffered channels to prevent blocking and collects results with error tracking.

package main

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"sync"
)

type Job struct {
	ConversationID string
	OutputDir      string
}

type Result struct {
	ConversationID string
	OutputPath     string
	Error          error
}

func Worker(ctx context.Context, id int, jobs <-chan Job, results chan<- Result, client *http.Client, tokenManager *TokenManager, orgURL string) {
	for job := range jobs {
		select {
		case <-ctx.Done():
			return
		default:
			token, err := tokenManager.GetToken()
			if err != nil {
				results <- Result{ConversationID: job.ConversationID, Error: fmt.Errorf("token fetch failed: %w", err)}
				continue
			}

			url := fmt.Sprintf("%s/api/v2/media/conversations/%s/audio", orgURL, job.ConversationID)
			req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
			if err != nil {
				results <- Result{ConversationID: job.ConversationID, Error: err}
				continue
			}
			req.Header.Set("Authorization", "Bearer "+token)
			req.Header.Set("Accept", "audio/wav")

			resp, err := doWithRetry(client, req, 3)
			if err != nil {
				results <- Result{ConversationID: job.ConversationID, Error: err}
				continue
			}

			if resp.StatusCode == http.StatusUnauthorized {
				resp.Body.Close()
				results <- Result{ConversationID: job.ConversationID, Error: fmt.Errorf("401 unauthorized for conversation %s", job.ConversationID)}
				continue
			}
			if resp.StatusCode == http.StatusForbidden {
				resp.Body.Close()
				results <- Result{ConversationID: job.ConversationID, Error: fmt.Errorf("403 forbidden for conversation %s", job.ConversationID)}
				continue
			}
			if resp.StatusCode != http.StatusOK {
				resp.Body.Close()
				results <- Result{ConversationID: job.ConversationID, Error: fmt.Errorf("unexpected status %d for conversation %s", resp.StatusCode, job.ConversationID)}
				continue
			}

			// Save raw stereo audio to temporary file
			tempFile := filepath.Join(job.OutputDir, fmt.Sprintf("temp_%s.wav", job.ConversationID))
			out, err := os.Create(tempFile)
			if err != nil {
				resp.Body.Close()
				results <- Result{ConversationID: job.ConversationID, Error: err}
				continue
			}

			_, err = io.Copy(out, resp.Body)
			out.Close()
			resp.Body.Close()
			if err != nil {
				os.Remove(tempFile)
				results <- Result{ConversationID: job.ConversationID, Error: fmt.Errorf("download failed: %w", err)}
				continue
			}

			// Convert to mono
			finalPath := filepath.Join(job.OutputDir, fmt.Sprintf("mono_%s.wav", job.ConversationID))
			if err := StereoToMono(tempFile, finalPath); err != nil {
				os.Remove(tempFile)
				results <- Result{ConversationID: job.ConversationID, Error: err}
				continue
			}
			os.Remove(tempFile)

			results <- Result{ConversationID: job.ConversationID, OutputPath: finalPath}
		}
	}
}

Step 3: Implement Stereo-to-Mono WAV Conversion

Genesys Cloud exports conversation audio as 16-bit PCM stereo WAV files. Downstream ML models or storage pipelines often require mono. The following function reads the raw PCM data, mixes the left and right channels arithmetically, and writes a new mono WAV file with preserved sample rate and bit depth.

package main

import (
	"fmt"
	"os"

	"github.com/go-audio/wav"
)

func StereoToMono(inputPath, outputPath string) error {
	inFile, err := os.Open(inputPath)
	if err != nil {
		return fmt.Errorf("failed to open input wav: %w", err)
	}
	defer inFile.Close()

	wavData, err := wav.Read(inFile)
	if err != nil {
		return fmt.Errorf("failed to parse wav: %w", err)
	}

	if wavData.Format.BitsPerSample != 16 {
		return fmt.Errorf("unsupported bit depth %d, only 16-bit PCM is supported", wavData.Format.BitsPerSample)
	}

	monoData := make([]int16, len(wavData.Data)/wavData.Format.Channels)
	channels := wavData.Format.Channels

	if channels == 1 {
		copy(monoData, wavData.Data)
	} else if channels == 2 {
		for i := 0; i < len(wavData.Data); i += 2 {
			left := wavData.Data[i]
			right := wavData.Data[i+1]
			monoData[i/2] = (left + right) / 2
		}
	} else {
		return fmt.Errorf("unsupported channel count %d", channels)
	}

	outFile, err := os.Create(outputPath)
	if err != nil {
		return fmt.Errorf("failed to create output wav: %w", err)
	}
	defer outFile.Close()

	monoWav := &wav.Wav{
		Format: wav.Format{
			Channels:      1,
			SampleRate:    wavData.Format.SampleRate,
			BitsPerSample: 16,
		},
		Data: monoData,
	}

	if err := wav.Write(outFile, monoWav); err != nil {
		return fmt.Errorf("failed to write mono wav: %w", err)
	}

	return nil
}

Step 4: Orchestrate the Download and Conversion Pipeline

The main orchestrator initializes the worker pool, dispatches conversation IDs, and collects results. It respects context cancellation and prints a summary upon completion.

package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"path/filepath"
)

func RunBatch(conversationIDs []string, outputDir string, workerCount int, orgURL, clientID, clientSecret string) {
	if err := os.MkdirAll(outputDir, 0755); err != nil {
		log.Fatalf("failed to create output directory: %v", err)
	}

	tokenManager := NewTokenManager(clientID, clientSecret, orgURL)
	client := NewMediaHTTPClient()
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	jobs := make(chan Job, workerCount*2)
	results := make(chan Result, len(conversationIDs))

	for w := 0; w < workerCount; w++ {
		go Worker(ctx, w, jobs, results, client, tokenManager, orgURL)
	}

	for _, convID := range conversationIDs {
		jobs <- Job{ConversationID: convID, OutputDir: outputDir}
	}
	close(jobs)

	successCount := 0
	failCount := 0
	for i := 0; i < len(conversationIDs); i++ {
		res := <-results
		if res.Error != nil {
			failCount++
			log.Printf("FAILED [%s]: %v", res.ConversationID, res.Error)
		} else {
			successCount++
			fmt.Printf("SUCCESS [%s]: %s\n", res.ConversationID, res.OutputPath)
		}
	}

	fmt.Printf("Batch complete: %d succeeded, %d failed\n", successCount, failCount)
}

Complete Working Example

The following script combines all components into a single executable. Replace the credential placeholders and conversation IDs before running.

package main

import (
	"fmt"
	"os"
)

func main() {
	if len(os.Args) < 6 {
		fmt.Println("Usage: go run main.go <org_url> <client_id> <client_secret> <output_dir> <conversation_id_1> [conversation_id_2 ...]")
		os.Exit(1)
	}

	orgURL := os.Args[1]
	clientID := os.Args[2]
	clientSecret := os.Args[3]
	outputDir := os.Args[4]
	conversationIDs := os.Args[5:]

	if len(conversationIDs) == 0 {
		fmt.Println("At least one conversation ID is required")
		os.Exit(1)
	}

	// Validate org URL format
	if orgURL[len(orgURL)-1] == '/' {
		orgURL = orgURL[:len(orgURL)-1]
	}

	RunBatch(conversationIDs, outputDir, 5, orgURL, clientID, clientSecret)
}

To execute the service:

go mod init genesys-audio-converter
go get github.com/go-audio/wav
go run main.go https://api.mypurecloud.com YOUR_CLIENT_ID YOUR_CLIENT_SECRET ./audio_output conv_12345678-1234-1234-1234-1234567890ab conv_87654321-4321-4321-4321-ba0987654321

Common Errors & Debugging

Error: 401 Unauthorized

• What causes it: The OAuth token has expired, the client credentials are invalid, or the scope media:audio:read is missing.
• How to fix it: Verify the client ID and secret in your Genesys Cloud security settings. Ensure the OAuth client has the media:audio:read scope assigned. The token manager automatically refreshes expired tokens, but initial credential mismatches will fail immediately.
• Code showing the fix: The TokenManager validates the response status code before caching. If you receive a 401 during the media API call, force a token refresh by clearing the cached token or verifying scope assignments in the admin console.

Error: 403 Forbidden

• What causes it: The OAuth client lacks permission to access the specific conversation, or the conversation belongs to a different Genesys Cloud organization.
• How to fix it: Assign the OAuth client to a security role that includes Media permissions. Verify that the conversation IDs exist in the target organization. Cross-organization audio access requires explicit data sharing configurations.

Error: 429 Too Many Requests

• What causes it: The worker pool exceeds the Genesys Cloud API rate limit for your account tier.
• How to fix it: Reduce the workerCount parameter in RunBatch. The doWithRetry function implements exponential backoff with jitter. If 429 errors persist after backoff, implement a global request rate limiter using golang.org/x/time/rate to cap requests per second.
• Code showing the fix: The retry loop in doWithRetry already handles 429 responses. Adjust the initial backoff delay if your account tier has stricter limits.

Error: unsupported bit depth or channel count

• What causes it: Genesys Cloud occasionally exports audio in 8-bit PCM or single-channel format depending on recording configuration.
• How to fix it: The StereoToMono function explicitly checks for 16-bit PCM. If you encounter other formats, add a conversion step using github.com/go-audio/convert before mixing. Validate the WAV header before processing.

Official References

• Genesys Cloud Media API Documentation
• Genesys Cloud OAuth 2.0 Guide
• go-audio/wav Package Reference
• Go Concurrency Patterns: Worker Pools