📜 Diagram for Lesson 12
Child Workflows & continueAsNew
Visualizing hierarchical workflow orchestration with child workflows and the continueAsNew pattern for managing workflow history
Hierarchical Workflow Orchestration
flowchart TD
A[OrderProcessingWorkflow - Parent] --> B[Start Child Workflows]
subgraph "Parallel Child Workflow Execution"
B --> C[PaymentWorkflow - Child 1]
B --> D[InventoryWorkflow - Child 2]
B --> E[ShippingWorkflow - Child 3]
C --> F[Validate Payment Method]
C --> G[Process Payment]
C --> H[Payment Complete]
D --> I[Check Inventory]
D --> J[Reserve Items]
D --> K[Inventory Reserved]
E --> L[Calculate Shipping]
E --> M[Schedule Pickup]
E --> N[Shipping Scheduled]
end
H --> O[Collect Child Results]
K --> O
N --> O
O --> P{All Children Successful?}
P -- Yes --> Q[Complete Order]
P -- No --> R[Handle Partial Failure]
style A fill:#e1f5fe
style C fill:#f3e5f5
style D fill:#f3e5f5
style E fill:#f3e5f5
style Q fill:#e8f5e8
continueAsNew Pattern
flowchart TD
subgraph "continueAsNew Pattern"
S[LongRunningWorkflow] --> T[Process Batch 1]
T --> U[Process Batch 2]
U --> V[Process Batch N]
V --> W{History Too Large?}
W -- Yes --> X[continueAsNew with current state]
W -- No --> Y[Continue Processing]
X --> Z[New Workflow Run with Reset History]
Z --> S
end
style X fill:#fff3e0
style Z fill:#fff3e0
continueAsNew prevents workflow history from growing too large by starting a new workflow run while preserving state
Child Workflow Benefits
graph TB
subgraph "Child Workflow Benefits"
AA[Independent Scaling]
BB[Isolated Failure Domains]
CC[Reusable Components]
DD[Parallel Execution]
end
style AA fill:#e8f5e8
style BB fill:#e8f5e8
style CC fill:#e8f5e8
style DD fill:#e8f5e8
Key Advantages:
- ✅ Independent Scaling: Each child can scale based on its workload
- ✅ Isolated Failure Domains: Child failures don't crash parent
- ✅ Reusable Components: Child workflows can be reused across parents
- ✅ Parallel Execution: Multiple children execute simultaneously
Orchestration Patterns
Parent-Child Coordination:
| Pattern | Use Case | Benefits |
|---|---|---|
| Sequential | Dependent operations | Clear ordering, simple error handling |
| Parallel | Independent operations | Faster execution, better resource usage |
| Dynamic | Variable complexity | Flexible, adaptive to requirements |
History Management:
- continueAsNew for long-running processes
- State preservation across workflow runs
- Memory optimization through history reset
💡 Key Orchestration Insights
What This Diagram Shows:
- ✅ Parent workflows orchestrate multiple child workflows in parallel
- ✅ Each child handles a specific domain of business logic
- ✅ continueAsNew pattern prevents workflow history from growing too large
- ✅ Hierarchical decomposition enables complex business process management
- ✅ Independent scaling and failure isolation improve system resilience
🚀 Production Benefits
This orchestration pattern provides:
- ✅ Scalable architecture through child workflow composition
- ✅ Fault tolerance with isolated failure domains
- ✅ Resource optimization through independent scaling
- ✅ Maintainable complexity with clear separation of concerns
- ✅ Long-running reliability through continueAsNew
Building robust, scalable distributed systems! 🎉