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Workflow Compilation

Before a workflow is executed by Temporal, it must be compiled from a UI-friendly graph (nodes and edges) into an execution-efficient DSL (Domain Specific Language).

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The Compiler Logic

The compiler lives in backend/src/dsl/compiler.ts.

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1. Filtering & Validation

  • Filters out UI-only nodes (e.g., text blocks, documentation).
  • Validates that every node references a registered component.
  • Ensures the workflow has exactly one Entry Point.

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2. Topological Sorting

The compiler uses a standard topological sort algorithm to determine the execution order and detect cycles.
  • Cycles: If node A depends on B and B depends on A, compilation fails.
  • Order: Nodes with zero dependencies are placed first.

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3. Dependency Mapping

For every node, the compiler calculates:
  • dependsOn: A list of node IDs that must complete before this node can start.
  • dependencyCounts: A pre-calculated map used by the executor to track readiness.

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4. Port & Variable Mapping

This is the most critical phase. The compiler maps Edges to Input Port mappings:
  • Maps sourceHandle (e.g., results) to targetHandle (e.g., domainList).
  • Ensures that if a port is connected via an edge, manual configuration values are handled according to valuePriority (usually ignoring manual values if a connection exists).

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Join Strategies

When a node has multiple incoming edges, it must decide when to execute:

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DSL Schema

The resulting JSON contains enough metadata for the Worker to rebuild the environment:
  • actions: Flat list of execution steps.
  • params: Manual configuration values.
  • inputMappings: Dynamic data flow instructions.
  • config: Global workflow settings (timeouts, environments).