Programmatically Pausing and Resuming CXone Outbound Campaigns Based on Real-Time Agent Availability Thresholds Using a Go Microservice

What You Will Build

• This microservice polls CXone agent availability every 30 seconds and automatically pauses or resumes outbound campaigns when active agents fall below or rise above a configured threshold.
• It uses the CXone Campaign REST API and the Interactions Agent Status API.
• The implementation uses Go with the standard library for HTTP communication, JSON serialization, context-aware timeouts, and concurrency-safe state tracking.

Prerequisites

• OAuth 2.0 client credentials with campaigns:read, campaigns:write, and interactions:agents:read scopes
• CXone API v2 base URL (typically https://YOUR_TENANT.eng.nicecxone.com)
• Go 1.21 or later
• No external dependencies required; the standard library provides all necessary functionality

Authentication Setup

CXone uses a standard OAuth 2.0 Client Credentials flow. The token endpoint expects a client_id, client_secret, and grant_type=client_credentials in the request body. The response contains an access_token and an expires_in duration in seconds. Tokens must be cached and refreshed before expiration to avoid 401 errors during polling cycles.

The following function handles token acquisition, expiration tracking, and automatic refresh. It also implements retry logic for 429 rate limit responses.

package main

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

type OAuthToken struct {
	AccessToken string `json:"access_token"`
	ExpiresIn   int    `json:"expires_in"`
	ExpiresAt   time.Time
}

type OAuthConfig struct {
	BaseURL     string
	ClientID    string
	ClientSecret string
}

var (
	tokenCache *OAuthToken
	tokenMu    sync.RWMutex
)

func getOAuthToken(ctx context.Context, cfg OAuthConfig) (*OAuthToken, error) {
	tokenMu.Lock()
	defer tokenMu.Unlock()

	// Return cached token if still valid
	if tokenCache != nil && time.Now().Before(tokenCache.ExpiresAt) {
		return tokenCache, nil
	}

	payload := fmt.Sprintf("client_id=%s&client_secret=%s&grant_type=client_credentials",
		cfg.ClientID, cfg.ClientSecret)

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, cfg.BaseURL+"/oauth2/token", bytes.NewBufferString(payload))
	if err != nil {
		return nil, fmt.Errorf("failed to create token request: %w", err)
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

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

	if resp.StatusCode == http.StatusTooManyRequests {
		return nil, fmt.Errorf("429 rate limit hit on token endpoint")
	}
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("token request failed with status %d: %s", resp.StatusCode, string(body))
	}

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

	token.ExpiresAt = time.Now().Add(time.Duration(token.ExpiresIn) * time.Second)
	// Subtract 60 seconds to refresh before hard expiration
	token.ExpiresAt = token.ExpiresAt.Add(-60 * time.Second)
	tokenCache = &token

	return tokenCache, nil
}

Required OAuth Scope: campaigns:read campaigns:write interactions:agents:read

Implementation

Step 1: Query Real-Time Agent Availability with Pagination

CXone returns agent status data in paginated responses. The /api/v2/interactions/agents endpoint accepts limit and offset query parameters. Each response contains an items array with agent objects that include a state field. Valid states include available, busy, offline, and wrap-up.

The following function fetches all available agents across pages. It handles pagination by incrementing the offset until the returned array is empty. It also implements a retry mechanism for 429 responses using exponential backoff.

func fetchAvailableAgents(ctx context.Context, baseURL string, token string) (int, error) {
	var totalAvailable int
	offset := 0
	limit := 100
	maxRetries := 3

	for {
		url := fmt.Sprintf("%s/api/v2/interactions/agents?limit=%d&offset=%d&state=available", baseURL, limit, offset)

		req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
		if err != nil {
			return 0, fmt.Errorf("failed to create agent request: %w", err)
		}
		req.Header.Set("Authorization", "Bearer "+token)
		req.Header.Set("Accept", "application/json")

		client := &http.Client{Timeout: 15 * time.Second}
		var resp *http.Response
		var body []byte

		// Retry logic for 429
		for attempt := 0; attempt <= maxRetries; attempt++ {
			resp, err = client.Do(req)
			if err != nil {
				return 0, fmt.Errorf("agent request failed: %w", err)
			}
			body, _ = io.ReadAll(resp.Body)
			resp.Body.Close()

			if resp.StatusCode != http.StatusTooManyRequests {
				break
			}
			if attempt == maxRetries {
				return 0, fmt.Errorf("429 rate limit exhausted on agent endpoint after %d attempts", maxRetries)
			}
			backoff := time.Duration(1<<uint(attempt)) * time.Second
			log.Printf("Hit 429 on agent fetch, retrying in %v", backoff)
			time.Sleep(backoff)
		}

		if resp.StatusCode != http.StatusOK {
			return 0, fmt.Errorf("agent request failed with status %d: %s", resp.StatusCode, string(body))
		}

		var page struct {
			Items []struct {
				ID   string `json:"id"`
				Name string `json:"name"`
				State string `json:"state"`
			} `json:"items"`
		}
		if err := json.Unmarshal(body, &page); err != nil {
			return 0, fmt.Errorf("failed to decode agent page: %w", err)
		}

		totalAvailable += len(page.Items)
		if len(page.Items) < limit {
			break
		}
		offset += limit
	}

	return totalAvailable, nil
}

Required OAuth Scope: interactions:agents:read

Step 2: Evaluate Thresholds and Manage Campaign State

Campaign status transitions must respect the current state to prevent API flapping. The system tracks whether the campaign is currently RUNNING or PAUSED. When available agents drop below the pause threshold, the system transitions to PAUSED. When available agents rise above the resume threshold, the system transitions back to RUNNING.

The following function sends a PUT request to /api/v2/campaigns/{campaignId} with a JSON body containing the status field. It includes full error handling and 429 retry logic.

func setCampaignStatus(ctx context.Context, baseURL, campaignID, token, targetStatus string) error {
	payload := map[string]string{"status": targetStatus}
	jsonBody, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("failed to marshal campaign status payload: %w", err)
	}

	url := fmt.Sprintf("%s/api/v2/campaigns/%s", baseURL, campaignID)
	maxRetries := 3

	for attempt := 0; attempt <= maxRetries; attempt++ {
		req, err := http.NewRequestWithContext(ctx, http.MethodPut, url, bytes.NewBuffer(jsonBody))
		if err != nil {
			return fmt.Errorf("failed to create campaign request: %w", err)
		}
		req.Header.Set("Authorization", "Bearer "+token)
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("Accept", "application/json")

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

		if resp.StatusCode == http.StatusTooManyRequests {
			if attempt == maxRetries {
				return fmt.Errorf("429 rate limit exhausted on campaign endpoint after %d attempts", maxRetries)
			}
			backoff := time.Duration(1<<uint(attempt)) * time.Second
			log.Printf("Hit 429 on campaign update, retrying in %v", backoff)
			time.Sleep(backoff)
			continue
		}

		if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusNoContent {
			return fmt.Errorf("campaign update failed with status %d: %s", resp.StatusCode, string(body))
		}

		log.Printf("Campaign %s status updated to %s", campaignID, targetStatus)
		return nil
	}

	return fmt.Errorf("unexpected retry loop exit for campaign %s", campaignID)
}

Required OAuth Scope: campaigns:write

Step 3: Orchestrate the Polling Loop

The main loop runs at a fixed interval. It fetches the OAuth token, queries agent availability, evaluates the threshold logic, and triggers status updates when necessary. The loop uses a context with cancellation support for graceful shutdown.

type ThresholdConfig struct {
	PauseThreshold int
	ResumeThreshold int
	PollingInterval time.Duration
}

func runPollingLoop(ctx context.Context, cfg OAuthConfig, campaignID string, thresholds ThresholdConfig) {
	ticker := time.NewTicker(thresholds.PollingInterval)
	defer ticker.Stop()

	isRunning := true // Assume campaign starts in RUNNING state

	for {
		select {
		case <-ctx.Done():
			log.Println("Polling loop stopped")
			return
		case <-ticker.C:
			token, err := getOAuthToken(ctx, cfg)
			if err != nil {
				log.Printf("Token refresh failed: %v", err)
				continue
			}

			available, err := fetchAvailableAgents(ctx, cfg.BaseURL, token.AccessToken)
			if err != nil {
				log.Printf("Agent fetch failed: %v", err)
				continue
			}

			log.Printf("Available agents: %d (Pause: %d, Resume: %d)", available, thresholds.PauseThreshold, thresholds.ResumeThreshold)

			if isRunning && available < thresholds.PauseThreshold {
				if err := setCampaignStatus(ctx, cfg.BaseURL, campaignID, token.AccessToken, "PAUSED"); err != nil {
					log.Printf("Failed to pause campaign: %v", err)
				} else {
					isRunning = false
				}
			} else if !isRunning && available >= thresholds.ResumeThreshold {
				if err := setCampaignStatus(ctx, cfg.BaseURL, campaignID, token.AccessToken, "RUNNING"); err != nil {
					log.Printf("Failed to resume campaign: %v", err)
				} else {
					isRunning = true
				}
			}
		}
	}
}

Complete Working Example

The following script combines all components into a single executable Go program. It reads configuration from environment variables, initializes the polling loop, and handles graceful shutdown via OS signals.

package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"os/signal"
	"syscall"
	"time"
)

func main() {
	baseURL := os.Getenv("CXONE_BASE_URL")
	clientID := os.Getenv("CXONE_CLIENT_ID")
	clientSecret := os.Getenv("CXONE_CLIENT_SECRET")
	campaignID := os.Getenv("CXONE_CAMPAIGN_ID")

	if baseURL == "" || clientID == "" || clientSecret == "" || campaignID == "" {
		log.Fatal("Missing required environment variables: CXONE_BASE_URL, CXONE_CLIENT_ID, CXONE_CLIENT_SECRET, CXONE_CAMPAIGN_ID")
	}

	cfg := OAuthConfig{
		BaseURL:      baseURL,
		ClientID:     clientID,
		ClientSecret: clientSecret,
	}

	thresholds := ThresholdConfig{
		PauseThreshold:  5,
		ResumeThreshold: 8,
		PollingInterval: 30 * time.Second,
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
	go func() {
		<-sigChan
		log.Println("Received shutdown signal, stopping polling loop")
		cancel()
	}()

	log.Printf("Starting campaign automation for %s", campaignID)
	runPollingLoop(ctx, cfg, campaignID, thresholds)
}

Expected HTTP Request/Response Cycle (Agent Fetch):

GET /api/v2/interactions/agents?limit=100&offset=0&state=available HTTP/1.1
Host: YOUR_TENANT.eng.nicecxone.com
Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...
Accept: application/json

HTTP/1.1 200 OK
Content-Type: application/json

{
  "items": [
    {
      "id": "agent-101",
      "name": "Maria Garcia",
      "state": "available"
    },
    {
      "id": "agent-102",
      "name": "James Wilson",
      "state": "available"
    }
  ]
}

Expected HTTP Request/Response Cycle (Campaign Pause):

PUT /api/v2/campaigns/cmp-884291 HTTP/1.1
Host: YOUR_TENANT.eng.nicecxone.com
Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...
Content-Type: application/json
Accept: application/json

{
  "status": "PAUSED"
}

HTTP/1.1 200 OK
Content-Type: application/json

{
  "id": "cmp-884291",
  "name": "Q3 Outreach Campaign",
  "status": "PAUSED",
  "updatedTimestamp": "2024-05-15T14:32:10Z"
}

Common Errors & Debugging

Error: 401 Unauthorized

• What causes it: The OAuth token has expired, the client credentials are incorrect, or the token was not attached to the request header.
• How to fix it: Verify that CXONE_CLIENT_ID and CXONE_CLIENT_SECRET match the CXone admin console. Ensure the Authorization: Bearer <token> header is present on every request. The provided code automatically refreshes tokens 60 seconds before expiration. If the error persists, manually call the token endpoint and validate the response structure.
• Code showing the fix: The getOAuthToken function already implements expiration tracking. If you encounter stale tokens, reduce the buffer period by changing token.ExpiresAt = token.ExpiresAt.Add(-60 * time.Second) to -120 * time.Second.

Error: 403 Forbidden

• What causes it: The OAuth client lacks the required scopes, or the token was issued with restricted permissions.
• How to fix it: Regenerate the OAuth client in the CXone administration panel and ensure campaigns:read, campaigns:write, and interactions:agents:read are explicitly selected. The token endpoint returns the granted scopes in the response; verify they match the requirement.
• Code showing the fix: No code change is required. Update the CXone OAuth client configuration and restart the microservice to fetch a fresh token with the correct scopes.

Error: 429 Too Many Requests

• What causes it: CXone enforces rate limits per tenant and per API path. Polling too frequently or making concurrent requests triggers this limit.
• How to fix it: The provided implementation includes exponential backoff retry logic for both the agent endpoint and the campaign endpoint. Increase the PollingInterval to 60 seconds if rate limits persist. Avoid running multiple instances of this microservice against the same campaign ID.
• Code showing the fix: The retry loops in fetchAvailableAgents and setCampaignStatus already handle 429 responses. If you need stricter control, add a Retry-After header parser:

if resp.StatusCode == http.StatusTooManyRequests {
    if delay, err := time.ParseDuration(resp.Header.Get("Retry-After") + "s"); err == nil {
        time.Sleep(delay)
    }
}

Error: 404 Not Found

• What causes it: The campaignID does not exist, the tenant URL is incorrect, or the campaign was deleted.
• How to fix it: Validate the campaign ID by calling GET /api/v2/campaigns/{campaignId} manually. Ensure the CXONE_BASE_URL points to the correct tenant region (e.g., eng.nicecxone.com for US East, eu1.nicecxone.com for Europe).
• Code showing the fix: Add a startup validation check before entering the polling loop:

req, _ := http.NewRequestWithContext(ctx, http.MethodGet, cfg.BaseURL+"/api/v2/campaigns/"+campaignID, nil)
req.Header.Set("Authorization", "Bearer "+token.AccessToken)
resp, _ := client.Do(req)
if resp.StatusCode == http.StatusNotFound {
    log.Fatalf("Campaign %s does not exist", campaignID)
}

Official References

• CXone Campaign API Documentation
• CXone Interactions Agent Status API
• CXone OAuth 2.0 Client Credentials Flow
• Go net/http Package Documentation