retry-and-error-handling

Retry and Error Handling

Demonstrates every retry mechanism and error handling pattern available in the Durable Task SDK.

Features Covered

Feature	API
Declarative retry	RetryPolicy with exponential backoff
Failure predicate	RetryPolicy.handleFailure
Custom retry handler	AsyncRetryHandler with custom delays
Sub-orchestration retry	callSubOrchestrator with retry options
Error inspection	state.raiseIfFailed(), state.failureDetails

Prerequisites

• Node.js ≥ 22
• Docker (for the DTS Emulator)

Setup

cd examples/azure-managed
docker compose up -d
cp .env.emulator .env
cd ../..
npm install && npm run build

Run

npm run example -- ./examples/azure-managed/retry-and-error-handling/index.ts

Expected Output

=== 1. RetryPolicy (exponential backoff) ===
Status: COMPLETED
Result: "Success on attempt 3 for \"retry-policy-...\""

=== 2. handleFailure Predicate ===
Status: COMPLETED
Result: "Success on attempt 3 for \"handle-failure-...\""

=== 3. Custom AsyncRetryHandler ===
Status: COMPLETED
Result: "Success on attempt 3 for \"custom-handler-...\""

=== 4. Sub-orchestration Retry ===
Status: COMPLETED
Result: {"sum":15}

=== 5. Error Handling (raiseIfFailed) ===
Status: FAILED
raiseIfFailed() threw: OrchestrationFailedError — ...
Failure type: Error
Failure message: FatalError: This operation cannot succeed

=== All retry/error demos completed successfully! ===

Smoke Test

npm run example -- ./examples/azure-managed/retry-and-error-handling/index.ts 2>&1 | grep "All retry/error demos completed successfully"

Running Against Azure Managed DTS (Cloud)

To run this sample against a real Azure Managed Durable Task Scheduler instead of the local emulator:

1. Create a scheduler and task hub (if you haven't already) — see the parent README for az durabletask commands.

2. Configure .env for your cloud endpoint:

   cd examples/azure-managed
   cp .env.example .env
   # Edit .env with your scheduler endpoint and task hub name

   Example .env:

   DURABLE_TASK_SCHEDULER_CONNECTION_STRING=Endpoint=https://your-scheduler.eastus.durabletask.io;Authentication=DefaultAzure;TaskHub=your-taskhub

3. Authenticate with Azure:

   az login

4. Run (no Docker needed):

   npm run example -- ./examples/azure-managed/retry-and-error-handling/index.ts