Lesson 15: External Service Integration

Workshop Guide

Learn how to integrate Temporal workflows with external services like APIs, databases, payment gateways, and notification systems

Overview

In this lesson, you'll learn how to integrate Temporal workflows with external services like APIs, databases, payment gateways, and notification systems.

This is critical for real-world applications where workflows need to orchestrate multiple external dependencies.

What You'll Learn

Core Integration Patterns:

• ✅ How to encapsulate external service calls within Temporal activities
• ✅ Different timeout and retry strategies for different service types
• ✅ Error handling patterns for graceful degradation
• ✅ Service-specific activity configurations
• ✅ Production-ready integration patterns

Your Task

Complete the ExternalServiceWorkflow implementation to:

1. ✅ Define comprehensive data classes for external service integration
2. ✅ Create activity interfaces for different service types (UserProfile, Payment, Database, Notification)
3. ✅ Configure appropriate activity options for external vs internal services
4. ✅ Implement the workflow logic with proper error handling and service orchestration
5. ✅ Handle partial failures gracefully while collecting detailed error information

Key Requirements

Integration Standards:

• ✅ All external service calls must happen within activities
• ✅ Use different timeout/retry configurations for different service types
• ✅ Implement graceful error handling that doesn't fail the entire workflow
• ✅ Return comprehensive results showing what succeeded and what failed
• ✅ Include proper logging and activity correlation

Files to Work With

Implementation Guide:

• ✅ workflow/ExternalServiceWorkflow.kt - Main workflow interface and implementation
• ✅ Follow the TODO comments to implement each section
• ✅ Reference the concept documentation for best practices
• ✅ Test with mock external services

Success Criteria

Your implementation should:

• ✅ Handle multiple external service integrations
• ✅ Use appropriate timeouts for different service types
• ✅ Collect and return all errors without failing early
• ✅ Demonstrate proper activity configuration patterns
• ✅ Show real-world integration scenarios

Service Integration Patterns

Service Categories:

🚀 Next Steps

After completing this lesson, you'll be ready for Lesson 16 where we'll cover:

• Testing strategies for complex workflows
• Production deployment considerations
• Monitoring and observability patterns
• Scaling external integrations

Ready to integrate with the world? Let's build! 🎉