Durable Functions Recipe

Orchestration workflows with Durable Task Scheduler as the backend.

Template Selection

Resource filter: durable Discover templates via MCP or CDN manifest where resource == "durable" and language matches user request.

Key Concept

Uses Durable Task Scheduler (DTS) — a fully managed backend for state persistence. Do NOT use Azure Storage queues/tables.

See Durable Task Scheduler reference for backend configuration details.

Troubleshooting

Orchestration Fails to Start

Cause: Durable Task Scheduler (DTS) backend not provisioned or connection misconfigured. Solution: Verify the DTS resource exists and the function app has the Durable Task Scheduler Worker role. Do NOT use Azure Storage queues/tables as backend.

UAMI Connection Issues

Cause: Missing or incorrect Durable Task Scheduler connection string. Solution: DTS uses a connection string format (not the __ suffix pattern). Set these app settings:

• DURABLE_TASK_SCHEDULER_CONNECTION_STRING: Endpoint=<scheduler-endpoint>;Authentication=ManagedIdentity;ClientID=<client-id>
• TASKHUB_NAME: name of the task hub

For system-assigned identity, omit ClientID: Endpoint=<scheduler-endpoint>;Authentication=ManagedIdentity

The identity must have the Durable Task Data Contributor role on the scheduler or task hub resource. See DTS identity auth for identity-based config — refer to the "Configure managed identity" section for connection string and role assignment details.

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