# lambda-java11

This project contains source code and supporting files for a serverless application that you can deploy with the SAM CLI. It includes the following files and folders.

- S3UpdateAcl/src/main - Code for the application's Lambda function which has sample code to update S3 ObjectACL to add grantee for the CanonicalID passed in via input parameters.
- events - Invocation events that you can use to invoke the function. 
- template.yaml - A template that defines the application's AWS resources.

If you prefer to use an integrated development environment (IDE) to build and test your application, you can use the AWS Toolkit.  
The AWS Toolkit is an open source plug-in for popular IDEs that uses the SAM CLI to build and deploy serverless applications on AWS. The AWS Toolkit also adds a simplified step-through debugging experience for Lambda function code. See the following links to get started.

* [CLion](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [GoLand](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [IntelliJ](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [WebStorm](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [Rider](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [PhpStorm](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [PyCharm](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [RubyMine](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [DataGrip](https://docs.aws.amazon.com/toolkit-for-jetbrains/latest/userguide/welcome.html)
* [VS Code](https://docs.aws.amazon.com/toolkit-for-vscode/latest/userguide/welcome.html)
* [Visual Studio](https://docs.aws.amazon.com/toolkit-for-visual-studio/latest/user-guide/welcome.html)

## Deploy the sample application

The Serverless Application Model Command Line Interface (SAM CLI) is an extension of the AWS CLI that adds functionality for building and testing Lambda applications. It uses Docker to run your functions in an Amazon Linux environment that matches Lambda. It can also emulate your application's build environment and API.

To use the SAM CLI, you need the following tools.

* SAM CLI - [Install the SAM CLI](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-install.html)
* Java11 - [Install the Java 11](https://docs.aws.amazon.com/corretto/latest/corretto-11-ug/downloads-list.html)
* Docker - [Install Docker community edition](https://hub.docker.com/search/?type=edition&offering=community)

To build and deploy your application for the first time, run the following in your shell:

```bash
sam build
sam deploy --guided
```

The first command will build the source of your application. The second command will package and deploy your application to AWS, with a series of prompts:

* **Stack Name**: The name of the stack to deploy to CloudFormation. This should be unique to your account and region, and a good starting point would be something matching your project name.
* **AWS Region**: The AWS region you want to deploy your app to.
* **Parameter CanonicalID**: The Valid ID of the cloudfront OAI to which you need object access. Value should be a 64 - 96 character long alphanumeric string.
* **Parameter Permission**: The permission needed for the object. Valid values are <READ|WRITE|READ_ACP|WRITE_ACP|FULL_CONTROL>
* **Confirm changes before deploy**: If set to yes, any change sets will be shown to you before execution for manual review. If set to no, the AWS SAM CLI will automatically deploy application changes.
* **Allow SAM CLI IAM role creation**: Many AWS SAM templates, including this example, create AWS IAM roles required for the AWS Lambda function(s) included to access AWS services. By default, these are scoped down to minimum required permissions. To deploy an AWS CloudFormation stack which creates or modifies IAM roles, the `CAPABILITY_IAM` value for `capabilities` must be provided. If permission isn't provided through this prompt, to deploy this example you must explicitly pass `--capabilities CAPABILITY_IAM` to the `sam deploy` command.
* **Save arguments to samconfig.toml**: If set to yes, your choices will be saved to a configuration file inside the project, so that in the future you can just re-run `sam deploy` without parameters to deploy changes to your application.

## Use the SAM CLI to build and test locally

Build your application with the `sam build` command.

```bash
lambda-java11$ sam build
```

The SAM CLI installs dependencies defined in `S3UpdateAcl/build.gradle`, creates a deployment package, and saves it in the `.aws-sam/build` folder.

Test a single function by invoking it directly with a test event. An event is a JSON document that represents the input that the function receives from the event source. Test events are included in the `events` folder in this project.

Run functions locally and invoke them with the `sam local invoke` command.

```bash
lambda-java11$ sam local invoke S3UpdateAcl --event events/event.json
```

## Configure the lambda function in S3 Batch Operations
Refer to this [blog post](blogpost link) to check out how this lambda can be configured to be triggered during S3 Batch Operations

**Note:** The sample code demonstrates how to update grantee based on type ID, but can easily updated to support other types as well, for e.g., URI or EmailAddress

## Cleanup

To delete the sample application that you created, use the AWS CLI. Assuming you used your project name for the stack name, you can run the following:

```bash
aws cloudformation delete-stack --stack-name lambda-java11
```

## Resources

See the [AWS SAM developer guide](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/what-is-sam.html) for an introduction to SAM specification, the SAM CLI, and serverless application concepts.

Next, you can use AWS Serverless Application Repository to deploy ready to use Apps that go beyond hello world samples and learn how authors developed their applications: [AWS Serverless Application Repository main page](https://aws.amazon.com/serverless/serverlessrepo/)