The Serverless Framework

A framework for quick easy microservices.

Who is this guy?

• chtompki@apache.org
• Software Developer (DevOps, Java, Python, TypeScript)
• Chief DevOps Engineer at Patch.com
• Apache Commons Committer
• Apache Member, and Jakarta EE Relations Manager
• Mathematician/Logician (?, sure why not).

Who has heard of "serverless computing?"

• Heard of AWS Lambda or Google Cloud Functions?
  • Execute snippets of code in different languages
• No infrastructure to manage, only configuration
• What does this look like?

Hello World AWS Lambda Function

import json

print('Loading function')


def lambda_handler(event, context):
    #print("Received event: " + json.dumps(event, indent=2))
    print("value1 = " + event['key1'])
    print("value2 = " + event['key2'])
    print("value3 = " + event['key3'])
    return event['key1']  # Echo back the first key value

Lambda Configuration

• Allocated 128mb memory
• Automatically provisioned CPU and network
• Bring your own code (node, python, java, c#, golang, ruby)
• Only pay for code executions.
  • Extraordinarily inexpensive
  • Approx $15/month for 500-1000 executions per minute

So what's a serverless API? How does that work?

Tying together the API Gateway and Lambda

import json

print('Loading function')


def lambda_handler(event, context):
    print("Received event: " + json.dumps(event, indent=2))
    response = {
        'statusCode': 200,
        'headers':{'x-hello-world':'some-header/value'},
        'body': event['body']
    }
    return response  # return the request body

Tying together the API Gateway and Lambda

Our deployed API

Example API Call

chtompki@Robs-MacBook-Pro ~ % curl \
  -X POST https://jnvg8rtlt8.execute-api.us-east-1.amazonaws.com/prod \
  -d '{"key1":"value1", "key2":"value2", "key3":"value3"}' && echo ""
{"key1":"value1", "key2":"value2", "key3":"value3"}

Benefits of serverless computing

• INEXPENSIVE!!! You only pay for time that the lambda is running
• Quickly deployable
• No infrastructure maintainance
• Quick integration with other AWS services (e.g. cloudwatch)

Drawbacks of serverless computing

• 15 minute call timeout (can't do major batch workloads)
• "Cold starts" - 500ms first call load time
• Global state weirdness.
• Max 1000 concurrent requests to a lambda.
• Database threadpool exhaustion concerns

Ok, great a lot of manual wiring and no DevOps. Seems not that great.

Queue the Serverless Application Framework

What is this "Serverless Application Framework?"

• https://github.com/serverless/serverless and https://www.serverless.com
• Open Source Project and CLI to help with serverless configuration and provisioning
• Similar to CloudFormation, but directed at making creating lambda applications easier.

serverless.yml

service: chtompki-serverless-example-api

frameworkVersion: '2'

provider:
  name: aws
  runtime: python3.8
  lambdaHashingVersion: '20201221'
  ## IMPORTANT: Serverless makes too many buckets
  deploymentBucket:
    name: chtompki-serverless-deployments
    serverSideEncryption: AES256

functions:
  hello:
    handler: lambda_function.lambda_handler
    events:
      - http:
          path: /
          method: post

sls deploy

We get a cloudformation deployment looking like this

API Gateway Looks really similar

Example API Call

chtompki@Robs-MacBook-Pro ~ % curl \
  -X POST https://cckfhngf25.execute-api.us-east-1.amazonaws.com/dev \
  -d '{"key1":"value1", "key2":"value2", "key3":"value3"}' && echo ""
{"key1":"value1", "key2":"value2", "key3":"value3"}

Let's Actually Explore the Project

https://github.com/chtompki/serverless-example

What else can we get from serverless?

1. Deployment to various collection of cloud providers
   • AWS, Azure, GCP, Knative, Tencent, Alibaba, Cloudflare, OpenWhisk, etc.
2. serverless.yml can declare all parts of CFT under resources section
3. plugins seciton of the serverless.yml allows importing other node modules that accommodate more customizations

Cool serverless plugins

• The serverless-offline plugin accommodates a full local serverless development environment
• The serverless-webpack plugin accommodates writing your lambda functions in typescript as opposed to simply javascript.
• The serverless-plugin-warmup keeps your lambdas warm so you don't have to deal with that pesky warm-up period.
• See https://www.serverless.com/blog/most-popular-framework-plugins for more

Questions?