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https://github.com/abhiyerra/aws-lambda-ts-template


https://github.com/abhiyerra/aws-lambda-ts-template

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README 

        
# OpsZeroTemplate



This is a sample template for OpsZeroTemplate - Below is a brief explanation of what we have generated for you:



```bash

.

├── README.md                   <-- This instructions file

├── hello-world                 <-- Source code for a lambda function

│   ├── app.js                  <-- Lambda function code

│   ├── package.json            <-- NodeJS dependencies

│   └── tests                   <-- Unit tests

│       └── unit

│           └── test_handler.js

└── template.yaml               <-- SAM template

```



## Requirements



* AWS CLI already configured with Administrator permission

* [NodeJS 8.10+ installed](https://nodejs.org/en/download/)

* [Docker installed](https://www.docker.com/community-edition)



## Setup process



### Building the project



[AWS Lambda requires a flat folder](https://docs.aws.amazon.com/lambda/latest/dg/nodejs-create-deployment-pkg.html) with the application as well as its dependencies in a node_modules folder. When you make changes to your source code or dependency manifest,

run the following command to build your project local testing and deployment:

 

```bash

sam build

```



If your dependencies contain native modules that need to be compiled specifically for the operating system running on AWS Lambda, use this command to build inside a Lambda-like Docker container instead:

```bash

sam build --use-container

```

 

By default, this command writes built artifacts to `.aws-sam/build` folder.



### Local development



**Invoking function locally through local API Gateway**



```bash

sam local start-api

```



If the previous command ran successfully you should now be able to hit the following local endpoint to invoke your function `http://localhost:3000/hello`



**SAM CLI** is used to emulate both Lambda and API Gateway locally and uses our `template.yaml` to understand how to bootstrap this environment (runtime, where the source code is, etc.) - The following excerpt is what the CLI will read in order to initialize an API and its routes:



```yaml

...

Events:

    HelloWorld:

        Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api

        Properties:

            Path: /hello

            Method: get

```



## Packaging and deployment



AWS Lambda NodeJS runtime requires a flat folder with all dependencies including the application. SAM will use `CodeUri` property to know where to look up for both application and dependencies:



```yaml

...

    FirstFunction:

        Type: AWS::Serverless::Function

        Properties:

            CodeUri: hello-world/

            ...

```



Firstly, we need a `S3 bucket` where we can upload our Lambda functions packaged as ZIP before we deploy anything - If you don't have a S3 bucket to store code artifacts then this is a good time to create one:



```bash

aws s3 mb s3://BUCKET_NAME

```



Next, run the following command to package our Lambda function to S3:



```bash

sam package \

    --template-file template.yaml \

    --output-template-file packaged.yaml \

    --s3-bucket REPLACE_THIS_WITH_YOUR_S3_BUCKET_NAME

```



Next, the following command will create a Cloudformation Stack and deploy your SAM resources.



```bash

sam deploy \

    --template-file packaged.yaml \

    --stack-name opszerotemplate \

    --capabilities CAPABILITY_IAM

```



> **See [Serverless Application Model (SAM) HOWTO Guide](https://github.com/awslabs/serverless-application-model/blob/master/HOWTO.md) for more details in how to get started.**



After deployment is complete you can run the following command to retrieve the API Gateway Endpoint URL:



```bash

aws cloudformation describe-stacks \

    --stack-name opszerotemplate \

    --query 'Stacks[].Outputs'

``` 



## Testing



We use `mocha` for testing our code and it is already added in `package.json` under `scripts`, so that we can simply run the following command to run our tests:



```bash

cd hello-world

npm install

npm run test

```



# Appendix



## AWS CLI commands



AWS CLI commands to package, deploy and describe outputs defined within the cloudformation stack:



```bash

sam package \

    --template-file template.yaml \

    --output-template-file packaged.yaml \

    --s3-bucket REPLACE_THIS_WITH_YOUR_S3_BUCKET_NAME



sam deploy \

    --template-file packaged.yaml \

    --stack-name opszerotemplate \

    --capabilities CAPABILITY_IAM \

    --parameter-overrides MyParameterSample=MySampleValue



aws cloudformation describe-stacks \

    --stack-name opszerotemplate --query 'Stacks[].Outputs'

```



**NOTE**: Alternatively this could be part of package.json scripts section.



## Bringing to the next level



Here are a few ideas that you can use to get more acquainted as to how this overall process works:



* Create an additional API resource (e.g. /hello/{proxy+}) and return the name requested through this new path

* Update unit test to capture that

* Package & Deploy



Next, you can use the following resources to know more about beyond hello world samples and how others structure their Serverless applications:



* [AWS Serverless Application Repository](https://aws.amazon.com/serverless/serverlessrepo/)