SubTasking

Shows sub-tasking with fan-out and fan-in: a parent task spawns multiple worker sub-tasks, then a joiner task aggregates their results.

What it does

1. The client submits a single “Launch” task with "Hello" as the payload.

2. The Launch task creates 5 “HelloWorker” sub-tasks, each producing its own result, then creates a “Joiner” task that declares those 5 results as data dependencies.

3. Each HelloWorker task appends its own task ID to the payload and writes the result.

4. The Joiner task reads all 5 dependencies, appends "_Joined" to each, concatenates them line by line, and writes the final result.

5. The client waits for the final result and prints each line.

The use-case is communicated through a custom TaskOptions.Options["UseCase"] field ("Launch", "HelloWorker", "Joiner").

Project structure

SubTasking/
├── Client/
│   └── Program.cs          # Submits the initial Launch task and retrieves the final result
└── Worker/
    ├── Program.cs           # Worker entry point
    └── SubTaskingWorker.cs  # ProcessAsync dispatcher: Launch / HelloWorker / Joiner

Key concepts

• Dispatching task behaviour at runtime via TaskOptions.Options

• Creating sub-task results with taskHandler.CreateResultsMetaDataAsync

• Submitting sub-tasks from within a worker with taskHandler.SubmitTasksAsync

• Expressing data dependencies between tasks using DataDependencies in TaskCreation

• Reading dependency data via taskHandler.DataDependencies

Running

Client

dotnet run --project Client -- \
  --endpoint http://localhost:5001 \
  --partition subtasking

Option	Default	Description
--endpoint	http://172.22.89.16:5001	ArmoniK control plane URL
--partition	subtasking	Partition to submit tasks to

Worker

dotnet run --project Worker

The worker reads its gRPC endpoint from environment variables (standard ArmoniK worker configuration).