AWS Lambda

1. Overview

AWS Lambda is Amazon Web Services' serverless computing service that allows you to run code without provisioning or managing servers. You simply upload your code, and Lambda handles all the scaling, maintenance, and monitoring of compute resources. Lambda functions can automatically execute in response to events (such as file uploads, API requests, database changes, etc.) and you only pay for actual usage.

Through GoInsight's Aws Lambda node, you can seamlessly integrate Lambda function invocation and management into your automation workflows. You can perform full lifecycle operations on Lambda functions, including:

• List functions: Retrieve a list of all Lambda functions in a specified region, obtaining function metadata information.
• Invoke functions: Synchronously or asynchronously invoke Lambda functions, pass JSON-formatted payload data, and retrieve execution results.

2. Prerequisites

Before using this node, you need to have a valid AWS account.

You need to have the following permissions:

• Access to AWS Lambda service
• Permission to create and manage IAM credentials
• For invoking functions, you need lambda:InvokeFunction permission on the target Lambda function
• For listing functions, you need lambda:ListFunctions permission

3. Credentials

For detailed instructions on how to obtain and configure credentials, please refer to our official documentation: Credentials Configuration Guide.

4. Supported Operations

The Aws Lambda node primarily operates around the core resource of Functions, supporting querying and invoking Lambda functions.

Summary

Operation Details

List Functions

Retrieves a list of AWS Lambda functions in a specific region, providing comprehensive function metadata using native Python libraries (requests, hashlib, hmac) instead of boto3.

Options:

• MaxItems: Maximum number of functions to return, default 50, max 50.
• SessionToken: Optional session token for temporary credentials.

Output:

• ListComplete (bool): Whether the function listing completed successfully.
• FunctionsCount (number): Number of functions found.
• FunctionsData (object-array): Array of function objects containing details.
• StatusCode (number): Operation status code.
• ErrorMessage (string): Error message if any.

Invoke Function

Invokes an AWS Lambda function synchronously or asynchronously with optional payload, providing comprehensive execution results using native Python libraries (requests, hashlib, hmac) instead of boto3.

Input Parameters:

• FunctionName: The name or ARN of the Lambda function to invoke.

Options:

• Payload: JSON formatted input data to pass to the function.
• InvocationType: Invocation type: RequestResponse or Event.
• Qualifier: Specify a version or alias, default $LATEST.
• SessionToken: Optional session token for temporary credentials.

Output:

• InvokeSuccess (bool): Whether the function invocation was successful.
• Result (string): The result returned by the function.
• ExecutedVersion (string): The version of the function that was executed.
• FunctionError (string): Function execution error type.
• StatusCode (number): HTTP status code.
• ErrorMessage (string): Error message if any.

5. Example Usage

This section will guide you through creating a simple workflow to invoke an AWS Lambda function. This example demonstrates how to synchronously invoke a Lambda function and retrieve execution results.

Workflow Overview: This example workflow consists of three nodes: Start -> Aws Lambda -> Answer. The Start node serves as the workflow entry point, the Aws Lambda node is responsible for invoking the Lambda function, and the Answer node is used to return execution results.

Step-by-Step Guide:

1. Add Tool Node:
   • In the workflow canvas, click the "+" button to add a new node.
   • In the popup panel, select the "Tools" tab.
   • Find and select Aws Lambda from the tool list.
   • In the list of supported operations for Aws Lambda, click to select Invoke Function, which will add a corresponding node to the canvas.
2. Configure Node:
   • Click the newly added Invoke Function node, and the configuration panel for this node will expand on the right side.
   • Credential Configuration: At the top of the panel, locate the credential field. Click the dropdown menu and select your already configured Aws Lambda credential.
   • Parameter Input: Detailed instructions on how to fill in the input parameters for this operation:
   • FunctionName: Enter the name or ARN of the Lambda function you want to invoke. For example, if your function name is my-test-function, simply enter my-test-function. If using an ARN, the format is similar to: arn:aws:lambda:us-east-1:123456789012:function:my-test-function.
   • Payload (optional): If you need to pass data to the function, enter a JSON-formatted string here. For example: {"key1": "value1", "key2": "value2"}. If the function doesn't require input data, you can leave this empty.
   • InvocationType (optional): Select the invocation type. RequestResponse means synchronous invocation, which waits for the function to complete and returns results; Event means asynchronous invocation, where the function executes in the background. The default value is RequestResponse.
   • Qualifier (optional): If you want to invoke a specific version or alias of the function, specify it here. For example, enter version number 1 or alias production. The default value is $LATEST, which means invoking the latest version.
3. Run and Verify:
   • After all required parameters are correctly filled in, the error prompt in the upper right corner of the workflow canvas will disappear.
   • Click the "Test Run" button in the upper right corner of the canvas to execute the workflow.
   • After successful execution, you can click the log icon in the upper right corner to view the detailed inputs and outputs of the node, verifying whether the operation was successful. You should see InvokeSuccess as true, and the Result field containing the result returned by the function.

Final Workflow Display: After completing the above steps, your entire workflow is configured. After clicking "Test Run", the specified Lambda function will be invoked, and execution results will be returned through the Answer node. You can view the function's execution status, return results, and any error messages in the logs.

6. FAQs

Q: When invoking a Lambda function, I get a 403 error indicating insufficient permissions. How should I handle this?

A: A 403 error usually indicates that your AWS credentials don't have sufficient permissions to invoke the Lambda function. Please check the following:

• Confirm that your IAM user or role has lambda:InvokeFunction permission.
• Check that your credentials are correctly configured, including Access Key ID and Secret Access Key.
• If using temporary credentials, ensure that SessionToken is correctly set and has not expired.
• Verify that the function name or ARN you're trying to invoke is correct.

Q: When invoking a function, I get a timeout error. What could be the cause?

A: Lambda function execution timeout may have the following causes:

• The function execution time exceeds Lambda's timeout limit (default 3 seconds, maximum 15 minutes).
• The function has long-running operations or blocking operations internally.
• Network connection issues preventing the function from accessing external resources.

It's recommended to check the function's execution logs, optimize the function code, or consider breaking long-running tasks into multiple steps.

Q: What format should the Payload parameter use?

A: The Payload parameter must be a valid JSON-formatted string. For example:

• Simple object: {"name": "test", "value": 123}
• Array: [1, 2, 3]
• Nested object: {"user": {"id": 1, "name": "John"}}

Please ensure the JSON string format is correct, otherwise the function may not be able to correctly parse the input data.

Q: How do I distinguish between synchronous and asynchronous invocation?

A: Control this through the InvocationType parameter:

• RequestResponse (synchronous): Waits for the function to complete execution and returns execution results. Suitable for scenarios where immediate results are needed.
• Event (asynchronous): Returns immediately, with the function executing in the background. Suitable for scenarios where results are not needed, such as event triggers, notifications, etc.

Q: When listing functions, I get an empty list. What could be the cause?

A: If you get an empty list, please check:

• Confirm that the AWS region you selected is correct, as function lists are independent across different regions.
• Check that your credentials have lambda:ListFunctions permission.
• Verify that Lambda functions actually exist in that region.
• Check if the MaxItems parameter is set too small.

7. Official Documentation

Aws Lambda Official API Documentation