AWS Lambda service allows you to run your code without needing to provision or configure any Servers. You get billed only for the compute time your code consumes. There is no charge when your code is not running. Currently, it supports Java, JavaScript, Python, Go, .Net, and Ruby.

You can even set your code to automatically trigger from other AWS services or call it directly from any web or mobile application. To get a glimpse of a sample use case, watch the introductory video present on the AWS Lambda webpage.

Step 1. Start the AWS Lambda Service

Log in to your AWS account, and go to the AWS Management Console. Navigate to the Lambda service.

Snapshot: Start Lamda from the AWS homepage.

Step 2. Launch the Wizard

You will be taken to the AWS Lambda dashboard. Launch the Create function wizard.

Snapshot: Lambda dashboard

Step 3. Create a Function

1. AWS provides three options to get the template code of your function:
   • Author from scratch – Start with a simple Hello World example.
   • Use a blueprint – Build a Lambda application from sample code and configuration presets for common use cases.
   • Browse serverless app repository – Deploy a sample Lambda application from the AWS Serverless Application Repository.
2. In the snapshot below, we have chosen the Use a blueprint option.

Snapshot: Choose the Use a blueprint option.

1. Choose a Runtime and the name of the template.

Snapshot: Filter Runtime: nodejs 12.x and Blueprint name: hello-world

1. Provide basic information about your function, such as the name, and permissions of your function. The permission decides which resources and actions your function has permission to access.
   In the snapshot below, we have chosen the default option Created a new role with basic Lambda permissions. In this case, the Lambda will create an execution role with permission to upload logs to Amazon CloudWatch Logs.

Snapshot: Choose a default role

Snapshot: The default code in the “hello-world” NodeJS application. Click on the “Create function”.

1. After the successful creation of the function, you see an acknowledgment. Remember, I mentioned that you can run your Lambda code in response to events. Now, you will have to create an Event that will trigger your code to run.
   Lambda provides a Designer user interface that allows choosing other AWS services, as event sources, to trigger your code, and use a destination (optional) of your choice to store the generated/processes output.
   In our example, let’s click on the Test button to create an Event that will be manually passed to your code.

Snapshot: Create an Event by clicking on the Test button

1. The Event is represented as a JSON file. Set three String values of your choice in the Event. A function can receive up to 10 test events.

Snapshot: Event is a JSON file. We will pass this Event to your code.

Step 4. Test Your Function

The snapshot below shows the Function code. Here, you can run the test, and see the output in the console below.

Snapshot: Run the Test, and observe the console output below the code.

Notice the Response, and the Function Logs. When you run the Test, the sample code accepts the event (JSON file) and processes the received information. In our case, we have printed all three JSON values on the console, and finally returned the first JSON value.

Step 5. Delete a Function

Even though you get billed only for the compute time your code consumes, we recommend you to delete your function if not in use. Deleting a function permanently removes the function code, however, the related IAM roles are retained in your account. You must delete the related IAM roles are well.

Snapshot: Delete a function