S3 Object Lambda - Process S3 Retrieved Data Inflight

The developer at Mystique Unicorn are interested in building their application using event-driven architecture. For those who are unfamiliar, An event-driven architecture uses events to trigger and communicate between decoupled services and is common in modern applications built with microservices. An event is a change in state, or an update, like an item being placed in a shopping cart on an e-commerce website.

In this application, they will have their physical stores, send sales and inventory related events to a central location like S3, where multiple downstream systems will consume these events. The event contains information about the product being ordered, price, discount and the store etc. A sample is provided below,

{
  "request_id": "ac616b1d-1c7a-4c04-b2a4-c616dc7c5025",
  "cust_id": 563,
  "category": "Cables",
  "evnt_time": "2021-04-04T11:41:40.414235",
  "evnt_type": "inventory_event",
  "price": 32.41,
  "discount": 8.4,
  "sku": 60912,
  "item_variant": "red",
  "gift_wrap": true,
  "qty": 24,
  "priority_shipping": true,
  "contact_me": "github.com/miztiik",
  "bad_msg": true
}

Not all of this information need to be accessible to all consumers. For example, the consumers from the inventory department does not need to know the product price and discount being offered. They do not want to change the original events and create multiple copies of the same event. Miztiik Unicorn is looking for a mechanism to filter out the sensitive information based on the consumer without modifying the original event.

Can you help them achieve the same?

🎯 Solutions

With the recently launched AWS feature - S3 Object Lambda, you can add your own code to S3 GET requests to modify and process data as it is returned to an application. S3 Object Lambda relies on AWS Lambda functions to automatically process the output of each request.

In this demo, we will create a the architecture like the one shown above. We will create a producer of store_events using lambda and persist them in our store events bucket. To provide secure access the data by different consumers, we will create S3 Access Point^4, ⁵. In our case, let us assume there will be a inventory customer running as a lambda function. We will call our access point lambda-consumer. This access point will be configured to execute a lambda function for all GET requests through its ARN. This lambda will redact the discount and price fields from the events and return to the user. We will use the GUI/CLI to simulate the consumer. A sample response is shown below.

{
  "request_id": "ac616b1d-1c7a-4c04-b2a4-c616dc7c5025",
  "cust_id": 563,
  "category": "Cables",
  "evnt_time": "2021-04-04T11:41:40.414235",
  "evnt_type": "inventory_event",
  "sku": 60912,
  "item_variant": "red",
  "gift_wrap": true,
  "qty": 24,
  "priority_shipping": true,
  "contact_me": "github.com/miztiik",
  "bad_msg": true
}

🧰 Prerequisites

This demo, instructions, scripts and cloudformation template is designed to be run in us-east-1. With few modifications you can try it out in other regions as well(Not covered here).
- 🛠 AWS CLI Installed & Configured - Get help here
- 🛠 AWS CDK Installed & Configured - Get help here
- 🛠 Python Packages, Change the below commands to suit your OS, the following is written for amzn linux 2
  - Python3 - yum install -y python3
  - Python Pip - yum install -y python-pip
  - Virtualenv - pip3 install virtualenv

⚙️ Setting up the environment

Get the application code

 git clone https://github.com/miztiik/s3-object-lambda-demo
 cd s3-object-lambda-demo

🚀 Prepare the dev environment to run AWS CDK

We will use cdk to make our deployments easier. Lets go ahead and install the necessary components.

 # You should have npm pre-installed
 # If you DO NOT have cdk installed
 npm install -g aws-cdk

 # Make sure you in root directory
 python3 -m venv .venv
 source .venv/bin/activate
 pip3 install -r requirements.txt

The very first time you deploy an AWS CDK app into an environment (account/region), you’ll need to install a bootstrap stack, Otherwise just go ahead and deploy using cdk deploy.

 cdk bootstrap
 cdk ls
 # Follow on screen prompts

You should see an output of the available stacks,

 store-events-bkt-stack
 store-events-producer-stack
 store-events-bkt-access-points-stack
 s3-object-lambda-stack

🚀 Deploying the application

Let us walk through each of the stacks,
- Stack: store-events-bkt-stack
  
  This stack will create the s3 bucket to hold all our store events. We will add a bucket policy to delegate all access management to be done by access points⁵.
  
  Initiate the deployment with the following command,
```
cdk deploy store-events-bkt-stack
```
  After successfully deploying the stack, Check the Outputs section of the stack. You will find the StoreEventsBucket.
- Stack: store-events-producer-stack
  
  This stack will create the lambda function that will generate the events and write them to StoreEventsBucket under prefix store_events.
  
  Initiate the deployment with the following command,
```
cdk deploy store-events-producer-stack
```
  After successfully deploying the stack, Check the Outputs section of the stack. You will find the StoreOrdersEventsProducer producer lambda function. We will invoke this function later during our testing phase.
- Stack: store-events-bkt-access-points-stack
  
  At this point, we will create our S3 access points. We have the IAM role arns of our consumer applications. To keep it simple, we will use the following prefix to provide access,
  - Access Point Name: lambda-consumer with access only to S3 Prefix: store_events
```
cdk deploy store-events-bkt-access-points-stack
```
  After successfully deploying the stack, Check the Outputs section of the stack. You will find the S3 Access Point Arn LambdaConsumerAccessPointArn. We will be using them during our testing to read/write to the StoreEventsBucket bucket.
- Stack: s3-object-lambda-stack
  
  At this point, we have all created all the prerequisites necessary for setting up our S3 Object Lambda for our access point lambda-consumer.
  - First will create lambda that will remove the fields discount and price from the incoming event and send the response back. Our lambda will need the new IAM permission type created for object lambda s3-object-lambda:WriteGetObjectResponse to respond back to the request. You can learn more about the permissions required for object lambda here².
  - Now we have our lambda function that can perform the redaction functionality, we will configure our object lambda access point lambda-consumer to process incoming requests.
  - Since this is a new functionality, the default boto3 packaged within lambda by AWS does not have the necessary libraries. I have packaged them as a lambda layer that gets deployed along with the function.
```
cdk deploy s3-object-lambda-stack
```
  After successfully deploying the stack, Check the Outputs section of the stack. You will find the S3 Object Lambda Access Point Arns S3ObjectLambdaArn. We will be using them during our testing to read/write to the StoreEventsBucket bucket.
  
  S3ObjectLambdaArn
🔬 Testing the solution
1. Invoke Producer Lambda: Let us start by invoking the lambda StoreOrdersEventsProducer from the producer stack using the AWS Console. If you want to ingest more events, invoke the lambda few times.
```
{
  "statusCode": 200,
  "body": "{\"message\": {\"status\": true, \"tot_msgs\": 12, \"bad_msgs\": 6, \"sales_evnts\": 5, \"inventory_evnts\": 7, \"tot_sales\": 562.13}}"
}
```
  Here in this invocation, We have ingested about 12 messages. Within those message, we have 5 sale events and 7 inventory events with a total sale value of 562.13.
2. Access Objects in S3:
  
  Although we can do it through CLI/SDK, the most easier way is to do it through GUI/Console. We will first try to access the data from S3 Bucket access,the normal way
  - S3 Console >> StoreEventsBucket >> Navigate to an object, an example shown below. You should be able to receive a JSON document with the full data including discount and price.
  - Now to test if we the restricted access is working fine, let us use the new Object Lambda Access Points on the left pane.
  - S3 Console >> Object Lambda Access Points >> miztiik-data-shield >> Navigate to an object, an example shown below.
    
    You should be able to download a JSON that has the discount and price fields removed.
  If you go back to the bucket and access the item directly from S3 bucket console (not from any of the access point), you will find that the original item is unmodified and still has the discount and price fields.
📒 Conclusion

Here we have demonstrated how to S3 Object lambda to process data requests in flight. You can extend this by adding a function to enrich the event with data from other sources.
🧹 CleanUp

If you want to destroy all the resources created by the stack, Execute the below command to delete the stack, or you can delete the stack from console as well
- Resources created during Deploying The Application
- Delete CloudWatch Lambda LogGroups
- Any other custom resources, you have created for this demo
```
# Delete from cdk
cdk destroy

# Follow any on-screen prompts

# Delete the CF Stack, If you used cloudformation to deploy the stack.
aws cloudformation delete-stack \
  --stack-name "MiztiikAutomationStack" \
  --region "${AWS_REGION}"
```
This is not an exhaustive list, please carry out other necessary steps as maybe applicable to your needs.

📌 Who is using this

This repository aims to show how to use S3 object lambda to new developers, Solution Architects & Ops Engineers in AWS. Based on that knowledge these Udemy course #1, course #2 helps you build complete architecture in AWS.

💡 Help/Suggestions or 🐛 Bugs

Thank you for your interest in contributing to our project. Whether it is a bug report, new feature, correction, or additional documentation or solutions, we greatly value feedback and contributions from our community. Start here

miztiik/s3-object-lambda-demo

S3 Object Lambda - Process S3 Retrieved Data Inflight

🎯 Solutions

🧰 Prerequisites

⚙️ Setting up the environment

🚀 Prepare the dev environment to run AWS CDK

🚀 Deploying the application

🔬 Testing the solution

📒 Conclusion

🧹 CleanUp

📌 Who is using this

💡 Help/Suggestions or 🐛 Bugs

👋 Buy me a coffee

📚 References

🏷️ Metadata