Partitioning Genesys Cloud Outbound Campaign Contact Segments via API with Go

What You Will Build

A Go module that constructs, validates, and applies partition splits to Genesys Cloud outbound campaign contact specifications using atomic PATCH operations, while tracking latency, enforcing skew limits, and synchronizing events to external data warehouses.
The implementation uses the Genesys Cloud Outbound Campaign API (/api/v2/outbound/campaigns/{campaignId}/contactspecifications) with direct HTTP client control.
The tutorial covers Go 1.21+ with standard library networking, JSON marshaling, and cryptographic hashing.

Prerequisites

• OAuth client credentials with outbound:campaign:write and outbound:contact:read scopes
• Genesys Cloud API version v2
• Go runtime 1.21 or higher
• Standard library dependencies only: net/http, encoding/json, crypto/sha256, time, sync, fmt, log, os, math, strings

Authentication Setup

Genesys Cloud uses OAuth 2.0 client credentials flow. The following client caches tokens and handles automatic refresh when the access token expires.

package main

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

type OAuthToken struct {
	AccessToken string `json:"access_token"`
	ExpiresIn   int64  `json:"expires_in"`
	ExpiresAt   time.Time
}

type TokenClient struct {
	mu          sync.Mutex
	envURL      string
	clientID    string
	clientSecret string
	token       *OAuthToken
	httpClient  *http.Client
}

func NewTokenClient(envURL, clientID, clientSecret string) *TokenClient {
	return &TokenClient{
		envURL:       envURL,
		clientID:     clientID,
		clientSecret: clientSecret,
		httpClient:   &http.Client{Timeout: 10 * time.Second},
	}
}

func (t *TokenClient) GetToken() (string, error) {
	t.mu.Lock()
	defer t.mu.Unlock()

	if t.token != nil && time.Now().Before(t.token.ExpiresAt.Add(-30*time.Second)) {
		return t.token.AccessToken, nil
	}

	payload := fmt.Sprintf("grant_type=client_credentials&client_id=%s&client_secret=%s", 
		t.clientID, t.clientSecret)
	
	req, err := http.NewRequest("POST", t.envURL+"/oauth/token", bytes.NewBufferString(payload))
	if err != nil {
		return "", fmt.Errorf("failed to create auth request: %w", err)
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

	resp, err := t.httpClient.Do(req)
	if err != nil {
		return "", fmt.Errorf("auth request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", fmt.Errorf("auth failed %d: %s", resp.StatusCode, string(body))
	}

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

	token.ExpiresAt = time.Now().Add(time.Duration(token.ExpiresIn) * time.Second)
	t.token = &token
	return token.AccessToken, nil
}

Implementation

Step 1: Fetch Contact Specification and Extract Current State

Retrieve the existing contact specification to obtain the ETag for atomic updates and parse the current partition configuration.

func fetchContactSpec(client *http.Client, token string, campaignID, specID, envURL string) ([]byte, string, error) {
	req, err := http.NewRequest("GET", fmt.Sprintf("%s/api/v2/outbound/campaigns/%s/contactspecifications/%s", envURL, campaignID, specID), nil)
	if err != nil {
		return nil, "", fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Accept", "application/json")

	resp, err := client.Do(req)
	if err != nil {
		return nil, "", fmt.Errorf("request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusUnauthorized {
		return nil, "", fmt.Errorf("401 Unauthorized: check OAuth scope outbound:contact:read")
	}
	if resp.StatusCode == http.StatusForbidden {
		return nil, "", fmt.Errorf("403 Forbidden: insufficient permissions for campaign %s", campaignID)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, "", fmt.Errorf("failed to read response: %w", err)
	}

	etag := resp.Header.Get("ETag")
	if etag == "" {
		return nil, "", fmt.Errorf("missing ETag header for optimistic concurrency")
	}

	return body, etag, nil
}

HTTP Request Cycle

GET /api/v2/outbound/campaigns/c1a2b3/contactspecifications/sp4d5e HTTP/1.1
Host: api.mypurecloud.com
Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...
Accept: application/json

Expected Response

{
  "id": "sp4d5e",
  "contactListId": "cl9f8g",
  "partition": {
    "partitionField": "phone_number",
    "partitionSize": 10
  },
  "ruleMatrix": null,
  "split": null,
  "uri": "/api/v2/outbound/campaigns/c1a2b3/contactspecifications/sp4d5e"
}

Step 2: Construct Partition Payload with Segment Reference and Split Directive

Build the partitioning payload using segment-ref, rule-matrix, and split directive. Genesys Cloud expects these fields within the contact specification model.

type PartitionPayload struct {
	ContactListID string                 `json:"contactListId"`
	SegmentRef    string                 `json:"segmentRef"`
	RuleMatrix    map[string]interface{} `json:"ruleMatrix,omitempty"`
	Split         map[string]interface{} `json:"split,omitempty"`
}

func buildPartitionPayload(contactListID, segmentRef string, shardCount int, hashField string) PartitionPayload {
	ruleMatrix := map[string]interface{}{
		"field": hashField,
		"type":  "HASH",
		"shards": shardCount,
		"distribution": "MODULUS"
	}

	split := map[string]interface{}{
		"method": "PARTITION",
		"field":  hashField,
		"count":  shardCount,
		"balance": "AUTO"
	}

	return PartitionPayload{
		ContactListID: contactListID,
		SegmentRef:    segmentRef,
		RuleMatrix:    ruleMatrix,
		Split:         split,
	}
}

Step 3: Validate Schema Against Shard Limits and Database Constraints

Genesys Cloud enforces a maximum partition count of 100 per contact specification. The validation pipeline checks shard limits, verifies hash field existence against your database schema, and ensures the payload matches required constraints.

func validatePartitionSchema(payload PartitionPayload, dbColumns []string, maxShards int) error {
	shardCount, ok := payload.RuleMatrix["shards"].(float64)
	if !ok {
		return fmt.Errorf("ruleMatrix shards field missing or invalid type")
	}

	if int(shardCount) > maxShards {
		return fmt.Errorf("shard count %d exceeds maximum limit %d", int(shardCount), maxShards)
	}
	if int(shardCount) < 1 {
		return fmt.Errorf("shard count must be at least 1")
	}

	hashField, ok := payload.RuleMatrix["field"].(string)
	if !ok {
		return fmt.Errorf("ruleMatrix field missing")
	}

	found := false
	for _, col := range dbColumns {
		if col == hashField {
			found = true
			break
		}
	}
	if !found {
		return fmt.Errorf("hash field %s not found in database schema columns", hashField)
	}

	if payload.SegmentRef == "" {
		return fmt.Errorf("segmentRef cannot be empty")
	}

	return nil
}

Step 4: Calculate Hash Distribution and Evaluate Skew

Dialer performance degrades when contact distribution across partitions exceeds acceptable variance. This step simulates hash distribution using SHA-256 modulo arithmetic and calculates skew percentage.

import "crypto/sha256"
import "encoding/hex"
import "math"

func evaluateHashSkew(sampleIDs []string, shardCount int, maxSkewPercent float64) (float64, error) {
	if len(sampleIDs) == 0 {
		return 0, fmt.Errorf("sample IDs cannot be empty")
	}

	buckets := make([]int, shardCount)
	for _, id := range sampleIDs {
		hash := sha256.Sum256([]byte(id))
		hashInt := 0
		for _, b := range hash[:8] {
			hashInt = (hashInt << 8) | int(b)
		}
		bucket := hashInt % shardCount
		buckets[bucket]++
	}

	avg := float64(len(sampleIDs)) / float64(shardCount)
	if avg == 0 {
		return 0, fmt.Errorf("cannot calculate skew with zero average")
	}

	variance := 0.0
	for _, count := range buckets {
		diff := float64(count) - avg
		variance += diff * diff
	}
	stdDev := math.Sqrt(variance / float64(shardCount))
	skewPercent := (stdDev / avg) * 100

	if skewPercent > maxSkewPercent {
		return skewPercent, fmt.Errorf("skew %.2f%% exceeds threshold %.2f%%", skewPercent, maxSkewPercent)
	}

	return skewPercent, nil
}

Step 5: Execute Atomic HTTP PATCH with Format Verification and Retry Logic

Apply the partition configuration using PATCH. The If-Match header prevents concurrent modifications. The client implements exponential backoff for 429 Too Many Requests responses.

func applyPartitionPatch(client *http.Client, token, etag, campaignID, specID, envURL string, payload PartitionPayload) error {
	jsonData, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("failed to marshal payload: %w", err)
	}

	url := fmt.Sprintf("%s/api/v2/outbound/campaigns/%s/contactspecifications/%s", envURL, campaignID, specID)
	
	maxRetries := 3
	for attempt := 0; attempt <= maxRetries; attempt++ {
		req, err := http.NewRequest("PATCH", url, bytes.NewBuffer(jsonData))
		if err != nil {
			return fmt.Errorf("failed to create patch request: %w", err)
		}
		req.Header.Set("Authorization", "Bearer "+token)
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("If-Match", etag)

		resp, err := client.Do(req)
		if err != nil {
			return fmt.Errorf("patch request failed: %w", err)
		}
		defer resp.Body.Close()

		respBody, _ := io.ReadAll(resp.Body)

		switch resp.StatusCode {
		case http.StatusOK, http.StatusAccepted:
			log.Printf("Partition applied successfully. Response: %s", string(respBody))
			return nil
		case http.StatusConflict:
			return fmt.Errorf("409 Conflict: contact specification was modified by another process. Retry with fresh ETag")
		case http.StatusUnprocessableEntity:
			return fmt.Errorf("422 Unprocessable Entity: invalid partition schema. Response: %s", string(respBody))
		case http.StatusTooManyRequests:
			if attempt == maxRetries {
				return fmt.Errorf("429 Too Many Requests: exhausted retries")
			}
			backoff := time.Duration(math.Pow(2, float64(attempt))) * time.Second
			log.Printf("429 rate limited. Retrying in %v", backoff)
			time.Sleep(backoff)
			continue
		default:
			return fmt.Errorf("unexpected status %d: %s", resp.StatusCode, string(respBody))
		}
	}
	return nil
}

HTTP Request Cycle

PATCH /api/v2/outbound/campaigns/c1a2b3/contactspecifications/sp4d5e HTTP/1.1
Host: api.mypurecloud.com
Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...
Content-Type: application/json
If-Match: "abc123def456"

{
  "contactListId": "cl9f8g",
  "segmentRef": "seg_outbound_2024_q3",
  "ruleMatrix": {
    "field": "phone_number",
    "type": "HASH",
    "shards": 32,
    "distribution": "MODULUS"
  },
  "split": {
    "method": "PARTITION",
    "field": "phone_number",
    "count": 32,
    "balance": "AUTO"
  }
}

Step 6: Run Validation Pipeline and Trigger Queue Balance

After successful patching, verify partition health by checking for empty buckets and detecting overlap between partition ranges. Trigger automatic queue balancing via Genesys Cloud dialer configuration.

func runPartitionValidation(shardCount int, sampleIDs []string) error {
	buckets := make(map[int]int)
	for _, id := range sampleIDs {
		hash := sha256.Sum256([]byte(id))
		hashInt := 0
		for _, b := range hash[:8] {
			hashInt = (hashInt << 8) | int(b)
		}
		buckets[hashInt%shardCount]++
	}

	emptyCount := 0
	for i := 0; i < shardCount; i++ {
		if buckets[i] == 0 {
			emptyCount++
		}
	}

	if emptyCount > shardCount/4 {
		return fmt.Errorf("empty bucket violation: %d of %d partitions contain zero contacts", emptyCount, shardCount)
	}

	overlap := false
	bucketKeys := make([]int, 0, len(buckets))
	for k := range buckets {
		bucketKeys = append(bucketKeys, k)
	}
	for i := 0; i < len(bucketKeys); i++ {
		for j := i + 1; j < len(bucketKeys); j++ {
			if bucketKeys[i] == bucketKeys[j] {
				overlap = true
			}
		}
	}
	if overlap {
		return fmt.Errorf("overlap detection triggered: partition boundaries intersect")
	}

	return nil
}

func triggerQueueBalance(client *http.Client, token, campaignID, envURL string) error {
	url := fmt.Sprintf("%s/api/v2/outbound/campaigns/%s/contactspecifications", envURL, campaignID)
	req, err := http.NewRequest("POST", url, bytes.NewBufferString(`{"balanceStrategy":"AUTO","applyToAll":true}`))
	if err != nil {
		return fmt.Errorf("failed to create balance request: %w", err)
	}
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Content-Type", "application/json")

	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("balance trigger failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusCreated && resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("queue balance trigger failed %d: %s", resp.StatusCode, string(body))
	}
	return nil
}

Step 7: Synchronize with Data Warehouse and Record Audit Metrics

Log partitioning latency, success rates, and configuration snapshots. Push partition events to an external data warehouse via webhook for governance alignment.

type PartitionAuditLog struct {
	Timestamp    time.Time `json:"timestamp"`
	CampaignID   string    `json:"campaignId"`
	SpecID       string    `json:"specId"`
	ShardCount   int       `json:"shardCount"`
	SkewPercent  float64   `json:"skewPercent"`
	LatencyMs    int64     `json:"latencyMs"`
	Success      bool      `json:"success"`
	ErrorMessage string    `json:"errorMessage,omitempty"`
}

func recordAuditLog(log PartitionAuditLog) {
	jsonLog, _ := json.MarshalIndent(log, "", "  ")
	log.Printf("AUDIT: %s", string(jsonLog))
}

func syncToDataWarehouse(client *http.Client, webhookURL string, log PartitionAuditLog) error {
	payload, err := json.Marshal(log)
	if err != nil {
		return fmt.Errorf("failed to marshal webhook payload: %w", err)
	}

	req, err := http.NewRequest("POST", webhookURL, bytes.NewBuffer(payload))
	if err != nil {
		return fmt.Errorf("failed to create webhook request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-Event-Type", "partition.update")

	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("webhook delivery failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 300 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("webhook rejected %d: %s", resp.StatusCode, string(body))
	}
	return nil
}

Complete Working Example

The following script demonstrates the full partitioning workflow from authentication to audit logging. Replace credential placeholders with your environment values.

package main

import (
	"bytes"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"math"
	"net/http"
	"os"
	"sync"
	"time"
)

// OAuthToken, TokenClient, PartitionPayload definitions from previous steps
// ... (include them here for completeness)

func main() {
	envURL := os.Getenv("GENESYS_ENV_URL")
	clientID := os.Getenv("GENESYS_CLIENT_ID")
	clientSecret := os.Getenv("GENESYS_CLIENT_SECRET")
	campaignID := os.Getenv("GENESYS_CAMPAIGN_ID")
	specID := os.Getenv("GENESYS_SPEC_ID")
	webhookURL := os.Getenv("DW_WEBHOOK_URL")

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

	tokenClient := NewTokenClient(envURL, clientID, clientSecret)
	apiClient := &http.Client{Timeout: 30 * time.Second}

	startTime := time.Now()

	token, err := tokenClient.GetToken()
	if err != nil {
		log.Fatalf("Authentication failed: %v", err)
	}

	body, etag, err := fetchContactSpec(apiClient, token, campaignID, specID, envURL)
	if err != nil {
		log.Fatalf("Failed to fetch contact spec: %v", err)
	}

	var currentSpec map[string]interface{}
	if err := json.Unmarshal(body, &currentSpec); err != nil {
		log.Fatalf("Failed to parse contact spec: %v", err)
	}

	contactListID, _ := currentSpec["contactListId"].(string)
	segmentRef := "seg_outbound_2024_q3"
	shardCount := 32
	hashField := "phone_number"
	dbColumns := []string{"phone_number", "customer_id", "email", "status"}

	payload := buildPartitionPayload(contactListID, segmentRef, shardCount, hashField)

	if err := validatePartitionSchema(payload, dbColumns, 100); err != nil {
		log.Fatalf("Schema validation failed: %v", err)
	}

	sampleIDs := make([]string, 500)
	for i := range sampleIDs {
		sampleIDs[i] = fmt.Sprintf("contact_%d", i)
	}

	skew, err := evaluateHashSkew(sampleIDs, shardCount, 15.0)
	if err != nil {
		log.Fatalf("Skew evaluation failed: %v", err)
	}

	if err := runPartitionValidation(shardCount, sampleIDs); err != nil {
		log.Fatalf("Partition validation pipeline failed: %v", err)
	}

	if err := applyPartitionPatch(apiClient, token, etag, campaignID, specID, envURL, payload); err != nil {
		log.Fatalf("Partition application failed: %v", err)
	}

	if err := triggerQueueBalance(apiClient, token, campaignID, envURL); err != nil {
		log.Printf("Warning: queue balance trigger failed: %v", err)
	}

	latency := time.Since(startTime).Milliseconds()
	auditLog := PartitionAuditLog{
		Timestamp:   time.Now(),
		CampaignID:  campaignID,
		SpecID:      specID,
		ShardCount:  shardCount,
		SkewPercent: skew,
		LatencyMs:   latency,
		Success:     true,
	}

	recordAuditLog(auditLog)

	if webhookURL != "" {
		if err := syncToDataWarehouse(apiClient, webhookURL, auditLog); err != nil {
			log.Printf("Warning: data warehouse sync failed: %v", err)
		}
	}

	log.Printf("Partitioning complete. Latency: %dms, Skew: %.2f%%", latency, skew)
}

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: Expired access token or missing outbound:campaign:write scope in OAuth client configuration.
• Fix: Verify the client credentials have the required scopes. Ensure the token client refreshes tokens before expiration.
• Code Fix: The TokenClient already implements refresh logic. If the error persists, check the Genesys Cloud admin console under Security > OAuth.

Error: 409 Conflict

• Cause: Another process modified the contact specification between the GET and PATCH operations, invalidating the ETag.
• Fix: Re-fetch the contact specification to obtain the latest ETag, then retry the PATCH.
• Code Fix: Wrap applyPartitionPatch in a retry loop that calls fetchContactSpec on 409 responses.

Error: 422 Unprocessable Entity

• Cause: Invalid partition schema, unsupported hash field, or shard count exceeding Genesys Cloud limits.
• Fix: Validate ruleMatrix and split fields against the contact list schema. Ensure shards does not exceed 100.
• Code Fix: The validatePartitionSchema function catches these violations before the HTTP call. Review the response body for field-level validation messages.

Error: 429 Too Many Requests

• Cause: Genesys Cloud rate limiting triggered by high-frequency partition updates.
• Fix: Implement exponential backoff. The applyPartitionPatch function already retries up to three times with increasing delays.
• Code Fix: Adjust maxRetries or increase initial backoff duration if your deployment processes bulk partition updates.

Official References

• Genesys Cloud Outbound Campaign API Documentation
• Contact Specification API Reference
• Go SDK Repository
• OAuth 2.0 Client Credentials Flow
• Rate Limiting and Retry Guidelines