Fan Out Fan In Workflow

patterns

Fan-out/fan-in pattern with work distribution to parallel workers, concurrent execution, result aggregation, and error handling for partial failures.

Download .fz file

Full FlowZap Code

Orchestrator { # Orchestrator
n1: circle label:"Start"
n2: rectangle label:"Receive batch request"
n3: rectangle label:"Split into work items"
n4: rectangle label:"Aggregate results"
n5: rectangle label:"Return combined response"
n6: circle label:"End"
n1.handle(right) -> n2.handle(left)
n2.handle(right) -> n3.handle(left)
n3.handle(bottom) -> Worker1.n7.handle(top) [label="Item 1"]
n3.handle(bottom) -> Worker2.n11.handle(top) [label="Item 2"]
n3.handle(bottom) -> Worker3.n15.handle(top) [label="Item 3"]
n4.handle(right) -> n5.handle(left)
n5.handle(right) -> n6.handle(left)
}
Worker1 { # Worker 1
n7: rectangle label:"Process work item"
n8: diamond label:"Processing successful?"
n9: rectangle label:"Return result"
n10: rectangle label:"Return error"
n7.handle(right) -> n8.handle(left)
n8.handle(right) -> n9.handle(left) [label="Yes"]
n8.handle(bottom) -> n10.handle(top) [label="No"]
n9.handle(top) -> Aggregator.n19.handle(bottom) [label="Result 1"]
n10.handle(top) -> Aggregator.n19.handle(bottom) [label="Error 1"]
}
Worker2 { # Worker 2
n11: rectangle label:"Process work item"
n12: diamond label:"Processing successful?"
n13: rectangle label:"Return result"
n14: rectangle label:"Return error"
n11.handle(right) -> n12.handle(left)
n12.handle(right) -> n13.handle(left) [label="Yes"]
n12.handle(bottom) -> n14.handle(top) [label="No"]
n13.handle(top) -> Aggregator.n19.handle(bottom) [label="Result 2"]
n14.handle(top) -> Aggregator.n19.handle(bottom) [label="Error 2"]
}
Worker3 { # Worker 3
n15: rectangle label:"Process work item"
n16: diamond label:"Processing successful?"
n17: rectangle label:"Return result"
n18: rectangle label:"Return error"
n15.handle(right) -> n16.handle(left)
n16.handle(right) -> n17.handle(left) [label="Yes"]
n16.handle(bottom) -> n18.handle(top) [label="No"]
n17.handle(top) -> Aggregator.n19.handle(bottom) [label="Result 3"]
n18.handle(top) -> Aggregator.n19.handle(bottom) [label="Error 3"]
}
Aggregator { # Aggregator
n19: rectangle label:"Wait for all workers"
n20: rectangle label:"Combine results"
n21: diamond label:"All succeeded?"
n22: rectangle label:"Return success"
n23: rectangle label:"Return partial failure"
n19.handle(right) -> n20.handle(left)
n20.handle(right) -> n21.handle(left)
n21.handle(right) -> n22.handle(left) [label="Yes"]
n21.handle(bottom) -> n23.handle(top) [label="No"]
n22.handle(top) -> Orchestrator.n4.handle(bottom) [label="Complete"]
n23.handle(top) -> Orchestrator.n4.handle(bottom) [label="Partial"]
}