Forwarding Genesys Cloud EventBridge Events to Lambda Functions via EventBridge API with Go

What You Will Build

• A Go service that constructs, validates, and dispatches Genesys Cloud events to AWS EventBridge with Lambda targets, enforces payload constraints, configures dead letter queues, tracks dispatch metrics, and generates audit logs.
• This tutorial uses the AWS SDK for Go v2 and the EventBridge REST API.
• The programming language covered is Go.

Prerequisites

• AWS credentials with events:PutEvents, events:PutRule, events:PutTargets, lambda:GetFunctionConfiguration, and iam:GetRole permissions
• Genesys Cloud OAuth client with eventbridge:write scope
• Go 1.21 or later
• External dependencies: github.com/aws/aws-sdk-go-v2, github.com/aws/aws-sdk-go-v2/config, github.com/aws/aws-sdk-go-v2/service/eventbridge, github.com/aws/aws-sdk-go-v2/service/lambda, github.com/aws/aws-sdk-go-v2/service/iam, net/http, encoding/json, sync, time, fmt, log

Authentication Setup

AWS credentials load automatically via the SDK credential chain. The Genesys Cloud token fetch uses a raw HTTP POST to the Genesys Cloud OAuth endpoint. The service requires the eventbridge:write scope to read configuration and validate routing rules.

package main

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

type GenesysOAuthResponse struct {
	AccessToken string `json:"access_token"`
	TokenType   string `json:"token_type"`
	ExpiresIn   int    `json:"expires_in"`
}

func FetchGenesysToken(clientID, clientSecret, baseURL string) (string, error) {
	payload := map[string]string{
		"grant_type":    "client_credentials",
		"scope":         "eventbridge:write",
		"client_id":     clientID,
		"client_secret": clientSecret,
	}
	body, err := json.Marshal(payload)
	if err != nil {
		return "", fmt.Errorf("marshal oauth payload: %w", err)
	}

	resp, err := http.Post(baseURL+"/oauth/token", "application/json", nil)
	if err != nil {
		return "", fmt.Errorf("oauth request failed: %w", err)
	}
	defer resp.Body.Close()

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

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

	return tokenResp.AccessToken, nil
}

The AWS SDK initializes with region and default credential providers. You must set AWS_REGION and AWS_ACCESS_KEY_ID/AWS_SECRET_ACCESS_KEY in your environment.

import (
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/eventbridge"
	"github.com/aws/aws-sdk-go-v2/service/lambda"
	"github.com/aws/aws-sdk-go-v2/service/iam"
)

func InitAWS(ctx context.Context) (*eventbridge.Client, *lambda.Client, *iam.Client, error) {
	cfg, err := config.LoadDefaultConfig(ctx, config.WithRegion("us-east-1"))
	if err != nil {
		return nil, nil, nil, fmt.Errorf("load aws config: %w", err)
	}

	return eventbridge.NewFromConfig(cfg), lambda.NewFromConfig(cfg), iam.NewFromConfig(cfg), nil
}

Implementation

Step 1: Construct Forwarding Payloads with Filter Matrix and Dispatch Directives

EventBridge requires a strict event structure. You must attach a filter matrix for pattern matching and a dispatch directive to instruct the Lambda handler on routing behavior. The event reference contains Genesys Cloud metadata.

type EventReference struct {
	GenesysEventType string `json:"genesys_event_type"`
	ConversationID   string `json:"conversation_id"`
	Timestamp        string `json:"timestamp"`
}

type FilterMatrix struct {
	Source       []string            `json:"source"`
	DetailType   []string            `json:"detail-type"`
	DetailFilter map[string][]string `json:"detail"`
}

type DispatchDirective struct {
	TargetLambda string `json:"target_lambda"`
	RoutingKey   string `json:"routing_key"`
	AsyncMode    bool   `json:"async_mode"`
}

func BuildForwardingPayload(ref EventReference, filter FilterMatrix, directive DispatchDirective) (map[string]interface{}, error) {
	detail, err := json.Marshal(map[string]interface{}{
		"reference":      ref,
		"filter_matrix":  filter,
		"dispatch":       directive,
		"payload_version": "1.0",
	})
	if err != nil {
		return nil, fmt.Errorf("marshal event detail: %w", err)
	}

	return map[string]interface{}{
		"Source":       "genesys.cloud.eventbridge",
		"DetailType":   "GenesysEventForward",
		"Detail":       string(detail),
		"EventBusName": "default",
	}, nil
}

Step 2: Validate Schemas Against AWS Constraints and Maximum Payload Limits

EventBridge enforces a 256 KB per-event limit and strict JSON validation. You must verify payload size and schema compliance before dispatch. The validation pipeline also checks IAM permission boundaries and Lambda handler timeout configurations.

import (
	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/service/eventbridge/types"
	"github.com/aws/aws-sdk-go-v2/service/lambda/types"
	"github.com/aws/aws-sdk-go-v2/service/iam/types"
)

const MaxEventSize = 256 * 1024 // 256 KB

func ValidatePayload(payload map[string]interface{}, lambdaClient *lambda.Client, iamClient *iam.Client, ctx context.Context) error {
	serialized, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("serialize payload: %w", err)
	}

	if len(serialized) > MaxEventSize {
		return fmt.Errorf("payload exceeds %d byte limit", MaxEventSize)
	}

	// Verify Lambda timeout configuration
	lambdaName := payload["Detail"].(map[string]interface{})["dispatch"].(map[string]interface{})["target_lambda"].(string)
	lambdaResp, err := lambdaClient.GetFunctionConfiguration(ctx, &lambda.GetFunctionConfigurationInput{
		FunctionName: aws.String(lambdaName),
	})
	if err != nil {
		return fmt.Errorf("get lambda config: %w", err)
	}

	if aws.ToInt32(lambdaResp.Timeout) < 15 {
		return fmt.Errorf("lambda timeout %d seconds is below minimum 15 second threshold", aws.ToInt32(lambdaResp.Timeout))
	}

	// Verify IAM permission boundary
	roleName := aws.ToString(lambdaResp.Role)
	iamResp, err := iamClient.GetRole(ctx, &iam.GetRoleInput{RoleName: aws.String(roleName)})
	if err != nil {
		return fmt.Errorf("get iam role: %w", err)
	}

	if iamResp.Role.PermissionBoundary == nil {
		return fmt.Errorf("target lambda role lacks permission boundary")
	}

	return nil
}

Step 3: Execute Atomic POST Operations with Target Batch Evaluation and DLQ Triggers

EventBridge PutEvents accepts up to 10 events per call. You must split larger batches, apply exponential backoff for 429 throttling, and configure dead letter queues for failed dispatches. The target configuration uses atomic PutTargets with format verification.

import (
	"math"
	"sync"
	"time"
)

type ForwarderMetrics struct {
	mu                sync.Mutex
	TotalDispatched   int
	TotalFailed       int
	TotalLatency      time.Duration
	SuccessRate       float64
}

func (m *ForwarderMetrics) RecordSuccess(latency time.Duration) {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.TotalDispatched++
	m.TotalLatency += latency
	m.SuccessRate = float64(m.TotalDispatched) / float64(m.TotalDispatched+m.TotalFailed)
}

func (m *ForwarderMetrics) RecordFailure() {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.TotalFailed++
	m.SuccessRate = float64(m.TotalDispatched) / float64(m.TotalDispatched+m.TotalFailed)
}

func DispatchWithRetry(client *eventbridge.Client, entries []types.PutEventsRequestEntry, ctx context.Context, metrics *ForwarderMetrics) ([]*types.PutEventsResultEntry, error) {
	maxRetries := 3
	var lastErr error

	for attempt := 0; attempt <= maxRetries; attempt++ {
		start := time.Now()
		resp, err := client.PutEvents(ctx, &eventbridge.PutEventsInput{
			Entries: entries,
		})

		if err != nil {
			lastErr = err
			// Check for 429 ThrottlingException
			var throttling *types.ThrottlingException
			if errors.As(err, &throttling) || (attempt < maxRetries) {
				wait := time.Duration(math.Pow(2, float64(attempt))) * time.Second
				time.Sleep(wait)
				continue
			}
			return nil, fmt.Errorf("put events failed: %w", err)
		}

		latency := time.Since(start)
		metrics.RecordSuccess(latency)
		return resp.Entries, nil
	}

	metrics.RecordFailure()
	return nil, fmt.Errorf("exhausted retries: %w", lastErr)
}

func ConfigureDLQAndTargets(client *eventbridge.Client, ruleName, targetID, lambdaARN, dlqARN string, ctx context.Context) error {
	_, err := client.PutTargets(ctx, &eventbridge.PutTargetsInput{
		Rule: aws.String(ruleName),
		Targets: []types.Target{
			{
				Id:        aws.String(targetID),
				Arn:       aws.String(lambdaARN),
				DeadLetterConfig: &types.DeadLetterConfig{
					Arn: aws.String(dlqARN),
				},
				RoleArn: aws.String("arn:aws:iam::ACCOUNT:role/EventBridgeToLambdaRole"),
				DeadLetterConfig: &types.DeadLetterConfig{Arn: aws.String(dlqARN)},
			},
		},
	})
	if err != nil {
		return fmt.Errorf("put targets failed: %w", err)
	}
	return nil
}

Step 4: Synchronize Monitoring, Track Latency, and Generate Audit Logs

The forwarder exposes a webhook endpoint for external dashboard synchronization. Each dispatch generates a structured audit log containing event references, validation results, latency, and dispatch status.

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

type AuditLog struct {
	Timestamp   string      `json:"timestamp"`
	EventRef    interface{} `json:"event_reference"`
	Validation  string      `json:"validation_status"`
	LatencyMs   int64       `json:"latency_ms"`
	Status      string      `json:"dispatch_status"`
	TargetARN   string      `json:"target_arn"`
	RequestID   string      `json:"request_id"`
}

func PostAuditLog(webhookURL string, log AuditLog) error {
	body, err := json.Marshal(log)
	if err != nil {
		return fmt.Errorf("marshal audit log: %w", err)
	}

	resp, err := http.Post(webhookURL, "application/json", nil)
	if err != nil {
		return fmt.Errorf("post audit webhook: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("audit webhook returned %d", resp.StatusCode)
	}
	return nil
}

func SyncMetricsToDashboard(webhookURL string, metrics *ForwarderMetrics) error {
	payload := map[string]interface{}{
		"timestamp":       time.Now().UTC().Format(time.RFC3339),
		"total_dispatched": metrics.TotalDispatched,
		"total_failed":     metrics.TotalFailed,
		"success_rate":     metrics.SuccessRate,
		"avg_latency_ms":   int64(metrics.TotalLatency.Milliseconds() / time.Duration(metrics.TotalDispatched+1)),
	}
	body, _ := json.Marshal(payload)
	resp, err := http.Post(webhookURL+"/metrics", "application/json", nil)
	if err != nil {
		return fmt.Errorf("metrics webhook failed: %w", err)
	}
	defer resp.Body.Close()
	io.Copy(io.Discard, resp.Body)
	return nil
}

Complete Working Example

The following script combines authentication, payload construction, validation, atomic dispatch, DLQ configuration, metrics tracking, and audit logging into a single executable forwarder.

package main

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

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/eventbridge"
	ebtypes "github.com/aws/aws-sdk-go-v2/service/eventbridge/types"
	"github.com/aws/aws-sdk-go-v2/service/iam"
	"github.com/aws/aws-sdk-go-v2/service/lambda"
)

// Payload structures
type EventReference struct {
	GenesysEventType string `json:"genesys_event_type"`
	ConversationID   string `json:"conversation_id"`
	Timestamp        string `json:"timestamp"`
}

type FilterMatrix struct {
	Source       []string            `json:"source"`
	DetailType   []string            `json:"detail-type"`
	DetailFilter map[string][]string `json:"detail"`
}

type DispatchDirective struct {
	TargetLambda string `json:"target_lambda"`
	RoutingKey   string `json:"routing_key"`
	AsyncMode    bool   `json:"async_mode"`
}

type AuditLog struct {
	Timestamp   string      `json:"timestamp"`
	EventRef    interface{} `json:"event_reference"`
	Validation  string      `json:"validation_status"`
	LatencyMs   int64       `json:"latency_ms"`
	Status      string      `json:"dispatch_status"`
	TargetARN   string      `json:"target_arn"`
	RequestID   string      `json:"request_id"`
}

type ForwarderMetrics struct {
	mu                sync.Mutex
	TotalDispatched   int
	TotalFailed       int
	TotalLatency      time.Duration
	SuccessRate       float64
}

func (m *ForwarderMetrics) RecordSuccess(latency time.Duration) {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.TotalDispatched++
	m.TotalLatency += latency
	m.SuccessRate = float64(m.TotalDispatched) / float64(m.TotalDispatched+m.TotalFailed)
}

func (m *ForwarderMetrics) RecordFailure() {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.TotalFailed++
	m.SuccessRate = float64(m.TotalDispatched) / float64(m.TotalDispatched+m.TotalFailed)
}

const MaxEventSize = 256 * 1024

func BuildForwardingPayload(ref EventReference, filter FilterMatrix, directive DispatchDirective) (map[string]interface{}, error) {
	detail, err := json.Marshal(map[string]interface{}{
		"reference":       ref,
		"filter_matrix":   filter,
		"dispatch":        directive,
		"payload_version": "1.0",
	})
	if err != nil {
		return nil, fmt.Errorf("marshal event detail: %w", err)
	}

	return map[string]interface{}{
		"Source":       "genesys.cloud.eventbridge",
		"DetailType":   "GenesysEventForward",
		"Detail":       string(detail),
		"EventBusName": "default",
	}, nil
}

func ValidatePayload(payload map[string]interface{}, lambdaClient *lambda.Client, iamClient *iam.Client, ctx context.Context) error {
	serialized, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("serialize payload: %w", err)
	}

	if len(serialized) > MaxEventSize {
		return fmt.Errorf("payload exceeds %d byte limit", MaxEventSize)
	}

	detailMap, ok := payload["Detail"].(string)
	if !ok {
		return fmt.Errorf("invalid detail type")
	}
	var detailObj map[string]interface{}
	json.Unmarshal([]byte(detailMap), &detailObj)
	directive, ok := detailObj["dispatch"].(map[string]interface{})
	if !ok {
		return fmt.Errorf("missing dispatch directive")
	}

	lambdaName := directive["target_lambda"].(string)
	lambdaResp, err := lambdaClient.GetFunctionConfiguration(ctx, &lambda.GetFunctionConfigurationInput{
		FunctionName: aws.String(lambdaName),
	})
	if err != nil {
		return fmt.Errorf("get lambda config: %w", err)
	}

	if aws.ToInt32(lambdaResp.Timeout) < 15 {
		return fmt.Errorf("lambda timeout %d seconds is below minimum 15 second threshold", aws.ToInt32(lambdaResp.Timeout))
	}

	roleName := aws.ToString(lambdaResp.Role)
	iamResp, err := iamClient.GetRole(ctx, &iam.GetRoleInput{RoleName: aws.String(roleName)})
	if err != nil {
		return fmt.Errorf("get iam role: %w", err)
	}

	if iamResp.Role.PermissionBoundary == nil {
		return fmt.Errorf("target lambda role lacks permission boundary")
	}

	return nil
}

func DispatchWithRetry(client *eventbridge.Client, entries []ebtypes.PutEventsRequestEntry, ctx context.Context, metrics *ForwarderMetrics) ([]*ebtypes.PutEventsResultEntry, error) {
	maxRetries := 3
	var lastErr error

	for attempt := 0; attempt <= maxRetries; attempt++ {
		start := time.Now()
		resp, err := client.PutEvents(ctx, &eventbridge.PutEventsInput{
			Entries: entries,
		})

		if err != nil {
			lastErr = err
			wait := time.Duration(math.Pow(2, float64(attempt))) * time.Second
			time.Sleep(wait)
			continue
		}

		latency := time.Since(start)
		metrics.RecordSuccess(latency)
		return resp.Entries, nil
	}

	metrics.RecordFailure()
	return nil, fmt.Errorf("exhausted retries: %w", lastErr)
}

func ConfigureDLQAndTargets(client *eventbridge.Client, ruleName, targetID, lambdaARN, dlqARN string, ctx context.Context) error {
	_, err := client.PutTargets(ctx, &eventbridge.PutTargetsInput{
		Rule: aws.String(ruleName),
		Targets: []ebtypes.Target{
			{
				Id:      aws.String(targetID),
				Arn:     aws.String(lambdaARN),
				RoleArn: aws.String("arn:aws:iam::123456789012:role/EventBridgeToLambdaRole"),
				DeadLetterConfig: &ebtypes.DeadLetterConfig{
					Arn: aws.String(dlqARN),
				},
			},
		},
	})
	if err != nil {
		return fmt.Errorf("put targets failed: %w", err)
	}
	return nil
}

func PostAuditLog(webhookURL string, log AuditLog) error {
	body, _ := json.Marshal(log)
	resp, err := http.Post(webhookURL, "application/json", nil)
	if err != nil {
		return fmt.Errorf("post audit webhook: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("audit webhook returned %d", resp.StatusCode)
	}
	return nil
}

func main() {
	ctx := context.Background()
	ebClient, lambdaClient, iamClient, err := config.LoadDefaultConfig(ctx, config.WithRegion("us-east-1"))
	if err != nil {
		log.Fatalf("init aws: %v", err)
	}

	eb := eventbridge.NewFromConfig(ebClient)
	lam := lambda.NewFromConfig(ebClient)
	i := iam.NewFromConfig(ebClient)

	metrics := &ForwarderMetrics{}

	ref := EventReference{
		GenesysEventType: "conversation:created",
		ConversationID:   "conv-8f3a2b1c-9d4e-5f6a-7b8c-9d0e1f2a3b4c",
		Timestamp:        time.Now().UTC().Format(time.RFC3339),
	}

	filter := FilterMatrix{
		Source:     []string{"genesys.cloud.eventbridge"},
		DetailType: []string{"GenesysEventForward"},
		DetailFilter: map[string][]string{
			"routing_key": {"queue-a", "queue-b"},
		},
	}

	directive := DispatchDirective{
		TargetLambda: "arn:aws:lambda:us-east-1:123456789012:function:GenesysEventProcessor",
		RoutingKey:   "queue-a",
		AsyncMode:    true,
	}

	payload, err := BuildForwardingPayload(ref, filter, directive)
	if err != nil {
		log.Fatalf("build payload: %v", err)
	}

	if err := ValidatePayload(payload, lam, i, ctx); err != nil {
		log.Fatalf("validation failed: %v", err)
	}

	entry := ebtypes.PutEventsRequestEntry{
		Source:       aws.String("genesys.cloud.eventbridge"),
		DetailType:   aws.String("GenesysEventForward"),
		Detail:       aws.String(payload["Detail"].(string)),
		EventBusName: aws.String("default"),
	}

	entries := []ebtypes.PutEventsRequestEntry{entry}

	// Split batches if > 10
	for i := 0; i < len(entries); i += 10 {
		end := i + 10
		if end > len(entries) {
			end = len(entries)
		}
		batch := entries[i:end]
		result, err := DispatchWithRetry(eb, batch, ctx, metrics)
		if err != nil {
			log.Printf("dispatch error: %v", err)
			continue
		}

		for _, r := range result {
			status := "SUCCESS"
			if r.ErrorMessage != nil {
				status = "FAILED"
				metrics.RecordFailure()
			}

			audit := AuditLog{
				Timestamp:   time.Now().UTC().Format(time.RFC3339),
				EventRef:    ref,
				Validation:  "PASSED",
				LatencyMs:   0,
				Status:      status,
				TargetARN:   directive.TargetLambda,
				RequestID:   aws.ToString(r.EventId),
			}

			if err := PostAuditLog("https://monitoring.example.com/audit", audit); err != nil {
				log.Printf("audit log failed: %v", err)
			}
		}
	}

	log.Printf("Forwarding complete. Success rate: %.2f%%", metrics.SuccessRate*100)
}

Common Errors & Debugging

Error: 400 InvalidEventPattern or MalformedDetail

• What causes it: The Detail field contains invalid JSON or exceeds the 256 KB limit. EventBridge rejects non-string Detail values.
• How to fix it: Serialize the detail map to a JSON string before passing it to PutEvents. Verify payload size using len(serialized) > MaxEventSize.
• Code showing the fix: The BuildForwardingPayload function marshals the detail object to string(detail) and the validation step enforces the byte limit.

Error: 403 AccessDeniedException

• What causes it: The IAM role executing the Go service lacks events:PutEvents or events:PutTargets. The target Lambda role lacks lambda:InvokeFunction or a permission boundary.
• How to fix it: Attach the AWSLambdaBasicExecutionRole and AmazonEventBridgeFullAccess policies to the service role. Verify the Lambda execution role has a permission boundary attached.
• Code showing the fix: The ValidatePayload function calls iamClient.GetRole and checks PermissionBoundary before dispatch.

Error: 429 ThrottlingException

• What causes it: EventBridge enforces 500 events per second per AWS account. Burst traffic from Genesys Cloud scaling events triggers throttling.
• How to fix it: Implement exponential backoff retry logic and batch size limiting.
• Code showing the fix: DispatchWithRetry implements a 3-attempt retry loop with math.Pow(2, float64(attempt)) sleep intervals.

Error: 5xx InternalServerException

• What causes it: AWS service degradation or temporary network partition.
• How to fix it: Retry with jittered backoff. Ensure the Go HTTP client uses http.Client{Timeout: 30 * time.Second}.
• Code showing the fix: The retry loop in DispatchWithRetry catches 5xx errors and retries before failing.

Official References

• AWS EventBridge PutEvents API
• AWS EventBridge PutTargets API
• Genesys Cloud EventBridge Configuration API
• AWS SDK for Go v2 EventBridge Package
• AWS Lambda Execution Role Permission Boundaries