Supported runtimes for durable functions

Durable functions are available for selected managed runtimes and OCI container images for additional runtime version flexibility. You can create durable functions for Node.js and Python using managed runtimes directly in the console or programmatically through infrastructure-as-code. Durable functions in Java (Preview) currently can only be deployed through container images.

Lambda managed runtimes

The following managed runtimes support durable functions when you create functions in the Lambda console or using the AWS CLI with the --durable-config '{"ExecutionTimeout": 3600, "RetentionPeriodInDays": 7}' parameter. For complete information about Lambda runtimes, see Lambda runtimes.

Node.js

Install the SDK in your Node.js project:

npm install @aws/durable-execution-sdk-js
      

The SDK supports JavaScript and TypeScript. For TypeScript projects, the SDK includes type definitions.

Python

Install the SDK in your Python project:

pip install aws-durable-execution-sdk-python
      

The Python SDK uses synchronous methods and doesn't require async/await.

Java (Preview)

Add a dependency to pom.xml:

<dependency>
    <groupId>software.amazon.lambda.durable</groupId>
    <artifactId>aws-durable-execution-sdk-java</artifactId>
    <version>VERSION</version>
</dependency>
      

Install the SDK in your Java project:

mvn install
      

A preview version of the Java SDK is available. The waitForCondition, waitForCallback, parallel and map operations are still in development.

Container images

You can use durable functions with container images to support additional runtime versions or custom runtime configurations. Container images let you use runtime versions not available as managed runtimes or customize your runtime environment.

To create a durable function using a container image:

Container example

Create a Dockerfile:

Python

Create a Dockerfile for Python 3.11:

FROM public.ecr.aws/lambda/python:3.11

# Copy requirements file
COPY requirements.txt ${LAMBDA_TASK_ROOT}/

# Install dependencies including durable SDK
RUN pip install -r requirements.txt

# Copy function code
COPY lambda_function.py ${LAMBDA_TASK_ROOT}/

# Set the handler
CMD [ "lambda_function.handler" ]
              

Create a requirements.txt file:

aws-durable-execution-sdk-python
              

Java (Preview)

Create a Dockerfile for Java 25:

FROM --platform=linux/amd64 public.ecr.aws/lambda/java:25

# Install Maven
RUN dnf install -y maven

WORKDIR /var/task

# Copy Maven configuration and source code
COPY pom.xml .
COPY src ./src

# Build
RUN mvn clean package -DskipTests

# Move JAR to lib directory
RUN mv target/*.jar lib/

# Set the handler
CMD ["src.path.to.lambdaFunction::handler"]
              

Build and push the image:

# Build the image
docker build -t my-durable-function .

# Tag for ECR
docker tag my-durable-function:latest 123456789012.dkr.ecr.us-east-1.amazonaws.com/my-durable-function:latest

# Push to ECR
docker push 123456789012.dkr.ecr.us-east-1.amazonaws.com/my-durable-function:latest
      

Create the function with durable execution enabled:

aws lambda create-function \
  --function-name myDurableFunction \
  --package-type Image \
  --code ImageUri=123456789012.dkr.ecr.us-east-1.amazonaws.com/my-durable-function:latest \
  --role arn:aws:iam::123456789012:role/lambda-execution-role \
  --durable-config '{"ExecutionTimeout": 3600, "RetentionPeriodInDays": 7}'
      

For more information about using container images with Lambda, see Creating Lambda container images in the Lambda Developer Guide.

Runtime considerations

SDK version management: Include the durable execution SDK in your deployment package or container image. This ensures your function uses a specific SDK version and isn't affected by runtime updates. Pin SDK versions in your package.json or requirements.txt to control when you upgrade.

Runtime updates: AWS updates managed runtimes to include security patches and bug fixes. These updates may include new SDK versions. To avoid unexpected behavior, include the SDK in your deployment package and test thoroughly before deploying to production.

Container image size: Container images have a maximum uncompressed size of 10 GB. The durable execution SDK adds minimal size to your image. Optimize your container by using multi-stage builds and removing unnecessary dependencies.

Cold start performance: Container images may have longer cold start times than managed runtimes. The durable execution SDK has minimal impact on cold start performance. Use provisioned concurrency if cold start latency is critical for your application.