Can an AWS Lambda function call another

Below is a detailed example of how you could set up a Lambda function in Node.js to invoke another Lambda function, incorporating some error handling and commenting for clarity.

This example assumes you have two Lambda functions:

1. CallerLambdaFunction – The function that will call the other Lambda function.
2. TargetLambdaFunction – The function that will be called by the CallerLambdaFunction.

CallerLambdaFunction Code Example

// Import the AWS SDK for Node.js
const AWS = require('aws-sdk');

// Initialize the Lambda service object with the desired region
const lambda = new AWS.Lambda({
  region: 'us-west-2' // Specify your AWS region
});

// The handler function AWS Lambda will invoke
exports.handler = async (event, context) => {
  // Define the parameters for invoking the target Lambda function
  const params = {
    FunctionName: 'TargetLambdaFunction', // The name of the Lambda function to invoke
    InvocationType: 'RequestResponse', // Invocation type: 'RequestResponse' for synchronous, 'Event' for asynchronous
    Payload: JSON.stringify({
      // Your payload here; this is the data you want to send to the target function
      key1: 'value1',
      key2: 'value2',
    }),
  };

  try {
    // Invoke the target Lambda function
    const response = await lambda.invoke(params).promise();

    // Process the response from the target Lambda function
    console.log('Response:', response);
    return JSON.parse(response.Payload);
  } catch (error) {
    // Handle any errors that occurred during the invocation
    console.error('Error invoking Lambda function:', error);
    throw error;
  }
};

Key Points:

• AWS SDK Initialization: The AWS.Lambda object is initialized with the region where your Lambda functions are deployed. You need to replace 'us-west-2' with the region that matches your deployment.
• Invocation Parameters: When calling lambda.invoke, you specify the FunctionName of the target Lambda, the InvocationType (synchronous or asynchronous), and any Payload you wish to pass. This payload must be a string, so objects are typically stringified with JSON.stringify.
• Error Handling: The code uses try/catch for error handling. If the target Lambda function invocation fails for any reason (e.g., function not found, execution error), the error will be caught and logged.
• Asynchronous Invocation: This example uses async/await for asynchronous function invocation, waiting for the promise returned by lambda.invoke(params).promise() to resolve.

Remember to adjust the region, function name, and payload according to your specific requirements and deployment.