Comparing Serverless Development with Step Functions, Chalice, and Python Async Methods

Introduction📝

When it comes to building serverless applications, several options are available for coordinating and executing tasks. AWS Step Functions 🤖 and the Chalice framework 🛠️ are two popular choices, but Python also provides built-in support for asynchronous programming through the async and await keywords 🔑. In this article, we will compare these three options and explore when to use each one to build scalable and maintainable serverless applications using Python 🐍.

Prerequisites 🧑‍💻

This article assumes that you have the following:

• Some essential knowledge of Python

• Know what is AWS step functions and lambda

• Are you familiar with serverless applications

Discussions 💬

AWS Step Functions is a service that allows you to create and run workflows that coordinate multiple AWS services, such as Lambda functions, DynamoDB tables, and SQS queues. These workflows, known as state machines, are defined using the JSON-based Amazon States Language. Step Functions provides a powerful way to visualize and understand the flow of your application, which can help with troubleshooting and debugging 🔍. However, it does add a layer of complexity, as you need to manage the state machine and its associated resources 🤔.

For example, consider a simple workflow that processes an image file uploaded to an S3 bucket. The workflow could consist of the following steps:

1). First, a Lambda function is triggered by the S3 event and resizes the image.📷

import json
import boto3

s3 = boto3.client('s3')

def resize_image(event, context):
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    # code to resize image
    s3.put_object(Bucket=bucket, Key=key, Body=resized_image)

2). Another Lambda function is triggered by the first one and applies the watermark to the image.💦

import json
import boto3

s3 = boto3.client('s3')

def apply_watermark(event, context):
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    # code to apply watermark
    s3.put_object(Bucket=bucket, Key=key, Body=watermarked_image)

3). A final Lambda function that stores the processed image in a different S3 bucket.📁

import json
import boto3

s3 = boto3.client('s3')

def store_image(event, context):
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    # code to get the processed image
    s3.put_object(Bucket='processed-images', Key=key, Body=processed_image)

Using step functions 🚀🧭

With Step Functions, you can define these steps in a state machine 📈 and have them executed in the specified order, with error handling 🤕 and retries built-in. This can significantly simplify the development process 🛠️ and make it easier to manage the application 💼.

Here is an example of a simple state machine for the Step Functions workflow:

{
"Comment": "A simple workflow that processes an image file uploaded to an S3 bucket",
"StartAt": "Resize Image",
"States": {
  "Resize Image": {
    "Type": "Task",
    "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:resize_image",
    "Next": "Apply Watermark"
  },
  "Apply Watermark": {
    "Type": "Task",
    "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:apply_watermark",
    "Next": "Store Image"
  },
  "Store Image": {
    "Type": "Task",
    "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:store_image",
    "End": true
  }
}
}

The above code block is an example of a state machine for the Step Functions workflow. It defines a simple workflow that processes an image file uploaded to an S3 bucket. The workflow consists of three steps: "Resize Image", "Apply Watermark", and "Store Image". Each step is represented by a state in the state machine and is executed in the specified order.

Using Chalice and Python Async methods 🔥🐍💻

It provides a simple, intuitive way to define and deploy Lambda functions 💻 and configure the associated resources, such as API Gateway endpoints 🌐 and IAM roles 🔒.

Chalice makes it easy to start serverless development 🛠, as it abstracts away many of the complexities of working with AWS services directly.

Here is an example of how the same example can be coordinated/invoked within Chalice and Python async methods:

from chalice import Chalice, Response
import json
import boto3
import asyncio

app = Chalice(app_name='image-processing')
s3 = boto3.client('s3')

@app.lambda_function()
def resize_image(event, context):
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    # code to resize image
    s3.put_object(Bucket=bucket, Key=key, Body=resized_image)
    apply_watermark.apply(event, context)

@app.lambda_function()
async def apply_watermark(event, context):
    await asyncio.sleep(1)
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    # code to apply watermark
    s3.put_object(Bucket=bucket, Key=key, Body=watermarked_image)
    store_image.apply(event, context)

@app.lambda_function()
async def store_image(event, context):
    await asyncio.sleep(1)
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    # code to get the processed image
    s3.put_object(Bucket='processed-images', Key=key, Body=processed_image)

In the above example, the resize_image function is invoked by the S3 event, and once it completes the execution, the apply_watermark function is called, and the same goes for the last function. Chalice framework handles the invocation of these functions and orchestrates them together.

🤓 If you're looking to build a serverless application using Python, you have several options! One popular option is AWS Step Functions, which allows you to easily coordinate multiple AWS services and simplify the development process for complex applications. Another option is the Chalice framework, which provides a simple and intuitive way to define and deploy Lambda functions and configure resources such as API Gateway endpoints and IAM roles.

💻 But perhaps the most exciting option is using Python's built-in support for asynchronous programming through the async and await keywords. This allows you to write non-blocking code, handling multiple tasks simultaneously, rather than waiting for one task to complete before starting the next. You have more control over the flow of your application and can take advantage of built-in libraries such as asyncio and aiohttp. However, it requires more expertise and experience with asynchronous programming, and you will need to handle things like scaling and error handling yourself.

🤔 Ultimately, the best choice will depend on the specific requirements of your application and your team's expertise. The Chalice framework may be the best choice if you build a simple application and want to start quickly. If you need more control over the flow of your application and are comfortable with asynchronous programming, then Python async methods may be a better fit. If you are building a complex application with multiple steps and decision points, AWS Step Functions can help simplify the development process.

💡 It's also worth noting that these three approaches are not mutually exclusive, and you can combine them to build more complex applications. For example, you could use Step Functions to coordinate the flow of your application and use Chalice and Python async methods to handle the logic of your application.

🚀 So, what are you waiting for? Take the first step towards building your dream serverless application using Python today! 🚀

Conclusion🤔

Building serverless applications with Python is a breeze with AWS Step Functions 🚀, the Chalice framework 🛠️, and Python async methods 💻. Each of these tools has its unique strengths and can be used to achieve different goals.

AWS Step Functions makes it super simple to coordinate and execute multiple Lambda functions in a specific order📝. At the same time, the Chalice framework takes the complexity out of deploying and configuring Lambda functions and other resources🌎. With Python async methods, you can build ultra-efficient and scalable applications that can handle high levels of concurrency🔥. Whether you're just getting started with serverless or are a seasoned pro, these tools are the perfect choice for your next project! So what are you waiting for? Give them a try and see the magic for yourself🌟🚀.

Don't hesitate to reach out to me on GitHub, Twitter, and LinkedIn if you have any questions or want to learn more. And don't forget to give a thumbs up, leave a comment and share this article with your network 😊.

References

• AWS Step Functions: aws.amazon.com/step-functions

• Chalice: aws.github.io/chalice

• Python's built-in support for asynchronous programming: docs.python.org/3/library/asyncio.html