Routing Genesys Cloud EventBridge Interactions to Multiple Downstream Systems via TypeScript

What You Will Build

• A TypeScript AWS Lambda consumer that processes Genesys Cloud disposition change events delivered via EventBridge.
• The consumer evaluates routing rules using a deterministic decision tree engine and dispatches transformed payloads to AWS SQS and Google Pub/Sub simultaneously.
• The consumer tracks correlation IDs across both message brokers, measures delivery latency, and publishes custom metrics to CloudWatch when thresholds are breached.

Prerequisites

• AWS IAM execution role with sqs:SendMessage, cloudwatch:PutMetricData, and logs:CreateLogGroup permissions
• Google Cloud service account with roles/pubsub.publisher assigned to the target topic
• Genesys Cloud tenant with EventBridge integration configured for conversation:disposition:change events
• Node.js 18+ and TypeScript 5+
• NPM dependencies: @aws-sdk/client-sqs, @aws-sdk/client-cloudwatch, @google-cloud/pubsub, uuid, zod, jmespath

Authentication Setup

The consumer is triggered by EventBridge, so no OAuth token exchange occurs inside the Lambda handler. EventBridge authenticates to your Lambda using AWS IAM, and your Lambda authenticates to downstream services using IAM roles and service account keys.

When configuring the Genesys Cloud EventBridge integration in the Admin Console or via the /api/v2/integrations/eventbridge endpoint, you must grant the analytics:export:read OAuth scope. This scope allows Genesys Cloud to stream conversation lifecycle events to your EventBridge event bus. The integration uses a private API key and secret managed by the EventBridge partner integration, not your application credentials.

# Environment variables required at runtime
export AWS_REGION=us-east-1
export SQS_QUEUE_URL=https://sqs.us-east-1.amazonaws.com/123456789012/disposition-routing-queue
export PUBSUB_TOPIC_ID=gen-conversation-events
export LATENCY_THRESHOLD_MS=450
export GOOGLE_APPLICATION_CREDENTIALS=/var/task/service-account-key.json

Implementation

Step 1: EventBridge Payload Parsing & Validation

EventBridge delivers Genesys Cloud events as HTTPS POST requests to the Lambda invocation endpoint. The payload follows the EventBridge event bus schema with Genesys Cloud data nested in the detail object.

HTTP Request from EventBridge:

POST /2015-03-31/functions/arn:aws:lambda:us-east-1:123456789012:function:DispositionConsumer/invocations HTTP/1.1
Host: lambda.us-east-1.amazonaws.com
Content-Type: application/json
X-Amz-Invocation-Type: Event
Authorization: AWS4-HMAC-SHA256 Credential=AKIA...

{
  "version": "0",
  "id": "a1b2c3d4-5678-90ab-cdef-EXAMPLE11111",
  "detail-type": "Genesys Cloud Conversation Disposition Change",
  "source": "genesys.cloud",
  "account": "123456789012",
  "time": "2024-05-15T14:30:00Z",
  "region": "us-east-1",
  "resources": ["arn:aws:events:us-east-1:123456789012:event-bus/genesys-cloud"],
  "detail": {
    "id": "8f3a2b1c-4d5e-6f7a-8b9c-0d1e2f3a4b5c",
    "type": "conversation",
    "disposition": {
      "code": "transferred",
      "name": "Transferred",
      "modifiedTime": "2024-05-15T14:30:00.000Z"
    },
    "queue": {
      "id": "q1w2e3r4-5t6y-7u8i-9o0p-a1s2d3f4g5h6",
      "name": "Sales"
    },
    "participants": [
      {
        "id": "p1a2s3d4-f5g6-h7j8-k9l0-z1x2c3v4b5n6",
        "type": "agent",
        "address": "+15550100"
      }
    ]
  }
}

We validate the incoming structure using Zod to guarantee type safety before routing. Invalid payloads are rejected immediately to prevent downstream processing errors.

import { z } from 'zod';

export const GenesysDispositionEventSchema = z.object({
  version: z.literal('0'),
  id: z.string().uuid(),
  'detail-type': z.string(),
  source: z.literal('genesys.cloud'),
  detail: z.object({
    id: z.string().uuid(),
    type: z.literal('conversation'),
    disposition: z.object({
      code: z.string(),
      name: z.string(),
      modifiedTime: z.string().datetime()
    }),
    queue: z.object({
      id: z.string().uuid(),
      name: z.string()
    }).nullable(),
    participants: z.array(z.object({
      id: z.string().uuid(),
      type: z.string(),
      address: z.string()
    }))
  })
});

export type ValidatedEvent = z.infer<typeof GenesysDispositionEventSchema>;

Step 2: Decision Tree Routing Logic

A flat rule list does not scale for complex business logic. We implement a recursive decision tree engine that evaluates conditions sequentially. Each node contains a condition function and two branches. The engine traverses until it reaches a terminal node with a routing target.

export interface DecisionNode {
  condition?: (event: ValidatedEvent) => boolean;
  target?: string;
  trueBranch?: DecisionNode;
  falseBranch?: DecisionNode;
}

export const routingTree: DecisionNode = {
  condition: (e) => e.detail.disposition.code === 'transferred',
  trueBranch: {
    condition: (e) => e.detail.queue?.name === 'Sales',
    trueBranch: { target: 'high-priority-sales' },
    falseBranch: { target: 'standard-transfer' }
  },
  falseBranch: {
    condition: (e) => e.detail.disposition.code === 'completed',
    trueBranch: { target: 'standard-completion' },
    falseBranch: { target: 'archive' }
  }
};

export function evaluateDecisionTree(event: ValidatedEvent, node: DecisionNode = routingTree): string {
  if (node.target) return node.target;
  if (!node.condition) throw new Error('Decision tree configuration error: missing condition or target');
  const result = node.condition(event);
  const branch = result ? node.trueBranch : node.falseBranch;
  if (!branch) throw new Error('Decision tree configuration error: missing branch');
  return evaluateDecisionTree(event, branch);
}

The tree structure allows you to add new conditions without modifying existing logic. You can serialize this tree to JSON and load it from S3 or Parameter Store at runtime for dynamic updates.

Step 3: Dual Dispatch with Correlation ID Tracking

We generate a single correlation ID per event and attach it to both message brokers. AWS SQS uses MessageAttributes, while Google Pub/Sub uses message attributes. We dispatch to both systems simultaneously using Promise.allSettled to ensure independent failure handling.

SQS HTTP Request (underlying SDK call):

POST / HTTP/1.1
Host: sqs.us-east-1.amazonaws.com
Content-Type: application/x-www-form-urlencoded; charset=utf-8
Authorization: AWS4-HMAC-SHA256 Credential=AKIA...
X-Amz-Date: 20240515T143000Z

Action=SendMessage&QueueUrl=https%3A%2F%2Fsqs.us-east-1.amazonaws.com%2F123456789012%2Fdisposition-routing-queue&MessageBody=%7B%22conversationId%22%3A%228f3a...%22%7D&MessageAttributes.correlationId.DataType=String&MessageAttributes.correlationId.StringValue=corr-9f8e7d6c-5b4a-3210-9876-fedcba987654

Pub/Sub HTTP Request (underlying SDK call):

POST /v1/projects/my-project/topics/gen-conversation-events:publish HTTP/1.1
Host: pubsub.googleapis.com
Content-Type: application/json
Authorization: Bearer ya29.c.Kp...

{
  "messages": [{
    "data": "eyJjb252ZXJzYXRpb25JZCI6IjhmM2EiLCJyb3V0ZSI6ImhpZ2gtcHJpb3JpdHktc2FsZXMifQ==",
    "attributes": {
      "correlation-id": "corr-9f8e7d6c-5b4a-3210-9876-fedcba987654",
      "route": "high-priority-sales"
    }
  }]
}

We implement exponential backoff for 429 rate-limit responses and wrap both dispatches in a single function.

import { SQSClient, SendMessageCommand, SQSServiceException } from '@aws-sdk/client-sqs';
import { PubSub, PubSubMessage, PubSubMessagePublishResult } from '@google-cloud/pubsub';
import { v4 as uuidv4 } from 'uuid';

const sqsClient = new SQSClient({ region: process.env.AWS_REGION });
const pubSubClient = new PubSub();

export interface DispatchResult {
  sqs: { success: boolean; error?: string };
  pubsub: { success: boolean; error?: string };
}

async function retryWithBackoff<T>(fn: () => Promise<T>, maxRetries: number = 3): Promise<T> {
  let lastError: Error | undefined;
  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    try {
      return await fn();
    } catch (err: any) {
      lastError = err;
      const isRateLimited = err.Code === 'TooManyRequests' || err.status === 429 || err.message?.includes('429');
      if (isRateLimited && attempt < maxRetries) {
        const delay = Math.pow(2, attempt) * 100;
        await new Promise(resolve => setTimeout(resolve, delay));
        continue;
      }
      throw err;
    }
  }
  throw lastError;
}

export async function dispatchToBrokers(
  payload: Record<string, unknown>,
  correlationId: string,
  route: string
): Promise<DispatchResult> {
  const messageAttributes = {
    correlationId: { stringValue: correlationId, dataType: 'String' },
    route: { stringValue: route, dataType: 'String' },
    timestamp: { stringValue: new Date().toISOString(), dataType: 'String' }
  };

  const sqsPromise = retryWithBackoff(() =>
    sqsClient.send(new SendMessageCommand({
      QueueUrl: process.env.SQS_QUEUE_URL!,
      MessageBody: JSON.stringify(payload),
      MessageAttributes: messageAttributes
    }))
  );

  const pubSubPromise = retryWithBackoff(() => {
    const message: PubSubMessage = {
      data: Buffer.from(JSON.stringify(payload)),
      attributes: {
        'correlation-id': correlationId,
        'route': route
      }
    };
    return pubSubClient.topic(process.env.PUBSUB_TOPIC_ID!).publish(message);
  });

  const [sqsResult, pubsubResult] = await Promise.allSettled([sqsPromise, pubSubPromise]);

  return {
    sqs: {
      success: sqsResult.status === 'fulfilled',
      error: sqsResult.status === 'rejected' ? sqsResult.reason.message : undefined
    },
    pubsub: {
      success: pubsubResult.status === 'fulfilled',
      error: pubsubResult.status === 'rejected' ? pubsubResult.reason.message : undefined
    }
  };
}

Step 4: Latency Tracking & CloudWatch Custom Metrics

We measure the duration from EventBridge receipt to successful dual dispatch. If the duration exceeds the configured threshold, we publish a custom metric to CloudWatch. The metric includes dimensions for routing status and failure type.

CloudWatch HTTP Request (underlying SDK call):

POST / HTTP/1.1
Host: monitoring.us-east-1.amazonaws.com
Content-Type: application/x-www-form-urlencoded; charset=utf-8
Authorization: AWS4-HMAC-SHA256 Credential=AKIA...

Action=PutMetricData&Namespace=GenesysRouting&MetricData.member.1.MetricName=DispositionRoutingLatency&MetricData.member.1.Unit=Milliseconds&MetricData.member.1.Value=485&MetricData.member.1.Dimensions.member.1.Name=RouteStatus&MetricData.member.1.Dimensions.member.1.Value=ThresholdBreached&Version=2010-08-01

import { CloudWatchClient, PutMetricDataCommand, CloudWatchServiceException } from '@aws-sdk/client-cloudwatch';

const cloudWatchClient = new CloudWatchClient({ region: process.env.AWS_REGION });
const NAMESPACE = 'GenesysRouting';

export async function publishLatencyMetric(
  durationMs: number,
  success: boolean,
  thresholdMs: number
): Promise<void> {
  const status = success ? 'Success' : 'Failure';
  const breached = durationMs > thresholdMs;
  const dimensionValue = breached ? 'ThresholdBreached' : status;

  await cloudWatchClient.send(new PutMetricDataCommand({
    MetricData: [
      {
        MetricName: 'DispositionRoutingLatency',
        Dimensions: [
          { Name: 'RouteStatus', Value: dimensionValue },
          { Name: 'Source', Value: 'EventBridge-Genesys' }
        ],
        Unit: 'Milliseconds',
        Value: durationMs
      }
    ],
    Namespace: NAMESPACE
  }));
}

Complete Working Example

import { EventBridgeEvent, Context } from 'aws-lambda';
import { GenesysDispositionEventSchema, ValidatedEvent } from './validation';
import { evaluateDecisionTree } from './decision-tree';
import { dispatchToBrokers } from './dispatch';
import { publishLatencyMetric } from './metrics';

export const handler = async (event: EventBridgeEvent<string, unknown>, context: Context): Promise<void> => {
  const startTime = Date.now();
  const thresholdMs = parseInt(process.env.LATENCY_THRESHOLD_MS || '450', 10);

  try {
    const parsed = GenesysDispositionEventSchema.parse(event);
    const route = evaluateDecisionTree(parsed);
    const correlationId = `corr-${context.awsRequestId}`;

    const transformedPayload = {
      conversationId: parsed.detail.id,
      dispositionCode: parsed.detail.disposition.code,
      queueName: parsed.detail.queue?.name ?? 'unassigned',
      participantCount: parsed.detail.participants.length,
      route,
      processedAt: new Date().toISOString()
    };

    const dispatchResult = await dispatchToBrokers(transformedPayload, correlationId, route);
    const allSuccess = dispatchResult.sqs.success && dispatchResult.pubsub.success;

    await publishLatencyMetric(Date.now() - startTime, allSuccess, thresholdMs);

    if (!allSuccess) {
      console.error('Partial dispatch failure:', JSON.stringify(dispatchResult));
    }
  } catch (error) {
    const duration = Date.now() - startTime;
    if (error instanceof Error && error.name === 'ZodError') {
      console.warn('Invalid EventBridge payload structure:', error.message);
    } else {
      console.error('Routing pipeline failure:', error);
    }
    await publishLatencyMetric(duration, false, thresholdMs);
  }
};

Common Errors & Debugging

Error: AccessDenied on Pub/Sub Publish

• What causes it: The Google Cloud service account lacks the roles/pubsub.publisher IAM role on the target topic.
• How to fix it: Grant the role in the Google Cloud Console or via gcloud projects add-iam-policy-binding.
• Code showing the fix: No code change is required. Verify the GOOGLE_APPLICATION_CREDENTIALS path points to a valid service account JSON file with the correct topic permissions.

Error: TooManyRequests on SQS SendMessage

• What causes it: Your Lambda concurrency exceeds the SQS queue rate limit (3000 transactions per second for standard queues, 1000 for FIFO).
• How to fix it: The retry utility implements exponential backoff. If failures persist, increase the queue rate limit in the AWS Console or implement a dead-letter queue for overflow.
• Code showing the fix: The retryWithBackoff function in Step 3 automatically catches 429 responses and retries with increasing delays.

Error: InvalidParameterType on CloudWatch PutMetricData

• What causes it: The metric value is passed as a string instead of a number, or the namespace contains unsupported characters.
• How to fix it: Ensure durationMs is cast to a number before publishing. Validate namespace against AWS naming rules (alphanumeric, hyphens, underscores only).
• Code showing the fix: Value: Number(durationMs) guarantees type compliance.

Error: EventBridge Payload Mismatch

• What causes it: Genesys Cloud updates the event schema, adding or removing fields in the detail object.
• How to fix it: Update the Zod schema to reflect the new structure. Use partial validation for optional fields during migration periods.
• Code showing the fix: Change .nullable() to .optional() in the Zod schema and add fallback logic in the decision tree.

Official References

• Genesys Cloud EventBridge Integration Documentation
• AWS SDK for JavaScript v3 SQS Client
• Google Cloud Pub/Sub Node.js Client
• CloudWatch PutMetricData API
• Zod Schema Validation Library