How to implement a lambda in Python?

Question

Pulumi · Accepted Answer

Sure! To implement a AWS Lambda function using Pulumi with Python, you first need to define a `aws.lambda_.Function` object and supply the necessary parameters, such as `runtime`, `code`, and `handler`.

Here is the example:
```python
import pulumi
import pulumi_aws as aws

# Define the lambda function
lambda_func = aws.lambda_.Function("my_lambda",
                                   role="your_iam_role_ARN",  # replace this with your IAM role ARN
                                   runtime="python3.8",  # define your lambda runtime
                                   code=pulumi.AssetArchive({
                                       '.': pulumi.FileArchive('./path_to_your_python_lambda')  # path to your Lambda function
                                   }),
                                   handler="lambda_function.lambda_handler"  # your handler function in your Lambda script
                                   )

pulumi.export('lambda_arn', lambda_func.arn)
```

In this example, we're creating a Lambda function named `my_lambda`. We specify the IAM role that the lambda should assume and also provide the runtime information – in this case, we use `python3.8`.

The `code` parameter is where we tell AWS where our lambda function code resides. For a Python function, we need to specify a `.zip` file or a directory. In this case, `pulumi.FileArchive('./path_to_your_python_lambda')` tells Pulumi to zip up everything in the `path_to_your_python_lambda` directory, and use that as the function source.

The `handler` is a string in the format of `file.function`. This tells AWS Lambda to execute the `lambda_handler` function within the `lambda_function.py` file.

Finally, we're exporting the ARN (Amazon Resource Name) of the Lambda function. Exporting properties like this allows you to easily use them in other parts of your Pulumi program, or in other Pulumi programs.

Please replace `"your_iam_role_ARN"` with your actual IAM Role ARN, `./path_to_your_python_lambda` with the actual path to your lambda function file and `lambda_function.lambda_handler` with the actual handler function in your Lambda script.

To run this program, put it in a file, say `__main__.py`, set up your AWS credentials, and run `pulumi up`.

Here is the [documentation](https://www.pulumi.com/registry/packages/aws/api-docs/lambda/function/) for the `aws.lambda_.Function` class.