# AWS Lambda to Amazon S3

This SAM template creates a Lambda function that writes to an S3 bucket when invoked.

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/lambda-s3-rust

Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the [AWS Pricing page](https://aws.amazon.com/pricing/) for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.

## Requirements

* [Create an AWS account](https://portal.aws.amazon.com/gp/aws/developer/registration/index.html) if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
* [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html) installed and configured
* [Git Installed](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git)
* [AWS Serverless Application Model](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-install.html) (AWS SAM) installed
* [Rust](https://www.rust-lang.org/) 1.56.0 or higher
* [cargo-zigbuild](https://github.com/messense/cargo-zigbuild) and [Zig](https://ziglang.org/) for cross-compilation

## Deployment Instructions

1. Create a new directory, navigate to that directory in a terminal and clone the GitHub repository:
    ``` 
    git clone https://github.com/aws-samples/serverless-patterns
    ```
2. Change directory to the pattern directory:
    ```
    cd lambda-s3-rust
    ```
3. Install dependencies and build:
    ```
    make build
    ```
4. From the command line, use AWS SAM to deploy the AWS resources for the pattern as specified in the template.yml file:
    ```
    make deploy
    ```
5. During the prompts:
    * Enter a stack name
    * Enter the desired AWS Region
    * Allow SAM CLI to create IAM roles with the required permissions.

    Once you have run `sam deploy -guided` mode once and saved arguments to a configuration file (samconfig.toml), you can use `sam deploy` in future to use these defaults.

6. Note the outputs from the SAM deployment process. These contain the resource names and/or ARNs which are used for testing.

## How it works

This SAM template creates a Lambda function that writes to an S3 bucket when invoked. Once you run `sam deploy --guided`, you will enter the name of the destination bucket for the objects to be stored.

## Testing

You can test the solution by accessing the Lambda console, finding your Lambda function, and clicking `Test` in the Code Source section. You can also invoke the function from the CLI using `aws lambda invoke --function-name ENTER_FUNCTION_NAME output.txt`. Then, go to the S3 console and ensure your object has been written to the bucket you specified.

## Cleanup
 
1. Delete the stack
    ```bash
    aws cloudformation delete-stack --stack-name STACK_NAME
    ```
2. Confirm the stack has been deleted
    ```bash
    aws cloudformation list-stacks --query "StackSummaries[?contains(StackName,'STACK_NAME')].StackStatus"
    ```
----
Copyright 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.

SPDX-License-Identifier: MIT-0