Task 105 — Workflow graph model + executor

Phase: 8 Status: pending Owner: — Slug: workflow-graph-executor Studio Stage: 8

Goal

Декларативная модель workflow-графа (nodes, edges, gateways) + executor/interpreter, который исполняет граф, драйвит ITaskLifecycleProtocol + ITaskQueue + IMeshBus.

Acceptance criteria

• WorkflowGraph model:
  • Nodes: StartNode, ServiceTaskNode, UserTaskNode, ConditionalNode, ParallelGatewayNode, ExclusiveGatewayNode, InclusiveGatewayNode, TimerEventNode, ErrorEventNode, EndNode
  • Edges: {from, to, condition?}
  • Metadata: name, version, description, template
• ServiceTaskNode: { agentId (or capability), intent, payload, timeoutMs, retryPolicy }

• [ ] UserTaskNode: { question, inputType (text

  file

  approval

  choice), choices[], timeoutMs }

• ConditionalNode: { expression, branches: {true: nodeId, false: nodeId} }

• [ ] ParallelGatewayNode: { branches: [nodeId[]], join: “all”

  “any” }

• TimerEventNode: { durationMs }
• ErrorEventNode: { catchFrom: nodeId, redirect: nodeId }
• WorkflowExecutor — interpreter:
  • ExecuteAsync(graph, input, cancellationToken) → WorkflowExecutionResult
  • Algorithm: traverse graph from Start, execute nodes, follow edges
  • ServiceTask: create IntentEnvelope → POST /api/mesh/intent (or via ITransport) → wait response
  • UserTask: create DelegatedTask with AwaitingInputContext → long-poll → user input → continue
  • Conditional: evaluate expression → branch
  • ParallelGateway: fork parallel tasks → join (wait all or any)
  • Timer: wait durationMs
  • Error: catch → redirect
  • Persistence: save node states after each transition
  • Cancellation: support cancel → cleanup

• [ ] Expression evaluator: simple (field access, ==, !=, >, <, &&,

  ) — no full DSL for MVP

• Unit tests: linear, conditional, parallel, user-task, timer, error scenarios
• dotnet build + dotnet test pass

Dependencies

• task_104 (workflow-server project) — executor lives there
• task_106 (DelegatedTask persistence) — for UserTask
• task_107 (parent/child tasks) — for parallel gateways

Scope / Likely files

src/workflow-server/Models/WorkflowGraph.cs, src/workflow-server/Executor/WorkflowExecutor.cs, src/workflow-server/Executor/ExpressionEvaluator.cs

Links

• Studio Stage 8: ../EPIC_Hercules_Studio/tasks/stage_08_workflow.md
• Backlog: ../backlog.md