aws-lambda-durable-functions

Create a new Lambda function with durable execution enabled at creation time, since it cannot be retrofitted to existing functions. Wrap your handler with withDurableExecution in TypeScript or the @durable_execution decorator in Python, then use context.step for checkpointed operations.

Durable functions require a qualified ARN: a specific version, an alias, or the $LATEST suffix. Invoking with an unqualified function name fails, so use formats like my-function:1 or my-function:live when calling aws lambda invoke.

Durable functions re-run code from the beginning on every invocation, with completed steps returning checkpointed results without re-executing. All non-deterministic code like Date.now(), Math.random(), and API calls must run inside steps to avoid corrupting execution state.

No, durable operations cannot be nested inside a step's callback. Use context.runInChildContext to group multiple operations like steps, waits, and invokes into a single logical unit instead.

Use LocalDurableTestRunner for TypeScript or DurableFunctionTestRunner for Python from the testing SDK packages. Always name operations and retrieve them by name rather than index, and use skipTime to fast-forward through waits.

The execution role must have the AWSLambdaBasicDurableExecutionRolePolicy managed policy, which grants lambda:CheckpointDurableExecution and lambda:GetDurableExecutionState. External callback systems additionally need lambda:SendDurableExecutionCallbackSuccess and Failure permissions.