Serverless computing enables you to build and run applications and services without thinking about servers. With AWS Lambda, our event-driven serverless compute service, you just upload your code and pay only for the compute time you consume. In this session, dive deep into AWS Lambda, and learn how to build high-availability serverless applications with complementary services, such as Amazon API Gateway, AWS Step Functions, Amazon Simple Queue Service (Amazon SQS), Amazon Simple Notification Service (Amazon SNS), and AWS CodePipeline.

1. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Serverless functions deep dive
Danilo Poccia
Principal Evangelist, Serverless
AWS
@danilop
Caroline Rennie
Product Lead
Comic Relief
@cagsr89

2. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
AWS operational responsibility models
On-Premises Cloud
Less More
Compute Virtual Machine
EC2 Elastic Beanstalk AWS LambdaFargate
Databases MySQL MySQL on EC2
RDS MySQL RDS Aurora Aurora Serverless DynamoDB
Storage Storage
S3
Messaging ESBs
Amazon MQ Kinesis SQS / SNS
Analytics
Hadoop Hadoop on EC2 EMR Elasticsearch Service Athena

3. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T

4. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Serverless applications
Services (anything)
Changes in
data state
Requests to
endpoints
Changes in
resource state
Event source Function
Node.js
Python
Java
C# / F# / PowerShell
Go
Ruby
Runtime API

5. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Anatomy of a Lambda function
Handler() function
Function to be executed
upon invocation
Event object
Data sent during Lambda
function Invocation
Context object
Methods available to
interact with runtime
information (request ID,
log group, more)
import json
def lambda_handler(event, context):
# TODO implement
return {
'statusCode': 200,
'body': json.dumps('Hello World!')
}

6. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Lambda Layers
Lets functions easily share code: Upload layer
once, reference within any function
Promote separation of responsibilities, lets
developers iterate faster on writing business logic
Built in support for secure sharing by ecosystem

7. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Using Lambda Layers
• Put common components in a ZIP file and
upload it as a Lambda Layer
• Layers are immutable and can be versioned
to manage updates
• When a version is deleted or permissions to
use it are revoked, functions that used it
previously will continue to work, but you
won’t be able to create new ones
• You can reference up to five layers, one of
which can optionally be a custom runtime
Lambda
Layers
arn:aws:lambda:region:accountId:layer:shared-lib
Lambda
Layers
arn:aws:lambda:region:accountId:layer:shared-lib:2
Lambda
Layers
arn:aws:lambda:region:accountId:layer:shared-lib:3

8. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Lambda Runtime API
Bring any Linux compatible language runtime
Powered by new Runtime API - Codifies the
runtime calling conventions and integration points
At launch, custom runtimes powering Ruby
support in AWS Lambda, more runtimes from
partners (like Erlang)
Custom runtimes distributed as “layers”
Rule
Stack

9. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Runtime Bootstrap
• The bootstrap executable act as a bridge
between the Runtime HTTP API and the
Function to be executed
• Bootstrap needs to manage response/error
handling, context creation and function
execution
• Information on the interface endpoint and the
function handler are shared as environment
variables
/runtime API
/invocation/next
/init/error /ID/error
/invocation/ID/response
/invocation/ID/error
bootstrap
Process events/headers
Clean up
Initialize and Invoke function
Response/Error handling
Lambda
Function

10. Build PCI and HIPAA compliant serverless applications!
Serverless platform services that can be used in both:

11. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Start with a framework
AWS
Chalice
AWS Amplify
AWS
SAM
AWS: Third-party:
Serverless
Framework

12. Meet
SAM!

13. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
AWS Serverless Application Model (SAM)
AWSTemplateFormatVersion: '2010-09-09’
Transform: AWS::Serverless-2016-10-31
Resources:
GetFunction:
Type: AWS::Serverless::Function
Properties:
Handler: index.get
Runtime: nodejs8.10
CodeUri: src/
Policies:
- DynamoDBReadPolicy:
TableName: !Ref MyTable
Events:
GetResource:
Type: Api
Properties:
Path: /resource/{resourceId}
Method: get
MyTable:
Type: AWS::Serverless::SimpleTable
Just 20 lines to create:
• Lambda function
• IAM role
• API Gateway
• DynamoDB table

14. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Use SAM CLI to package and deploy SAM templates
pip install --user aws-sam-cli
sam init --name my-app --runtime python
cd my-app/
sam local ... # generate-event/invoke/start-api/start-lambda
sam validate # The SAM template
sam build # Depending on the runtime
sam package --s3-bucket my-packages-bucket
--output-template-file packaged.yaml
sam deploy --template-file packaged.yaml
--stack-name my-stack-prod
sam logs -n MyFunction --stack-name my-stack-prod -t # Tail
sam publish # To the Serverless Application Repository
CodePipeline
Use
CloudFormation
deployment actions
with any SAM
application
Jenkins
Use SAM CLI plugin

15. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T

16. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
TweetSource:
Type: AWS::Serverless::Application
Properties:
Location:
ApplicationId: arn:aws:serverlessrepo:...
SemanticVersion: 2.0.0
Parameters:
TweetProcessorFunctionName: !Ref MyFunction
SearchText: '#serverless -filter:nativeretweets'
Nested apps to simplify solving recurring problems
Standard
Component
Custom
Business
Logic
Polling schedule
(CloudWatch
Events rule)
trigger
TwitterProcessor
SearchCheckpoint
TwitterSearchPoller
Twitter
Search API

17. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
AWS SAM Template Capabilities
• Can mix in other non-SAM CloudFormation
resources in the same template
• i.e. Amazon S3, Amazon Kinesis, AWS Step Functions
• Supports use of Parameters, Mappings,
Outputs, etc
• Supports Intrinsic Functions
• Can use ImportValue
(exceptions for RestApiId, Policies, StageName attributes)
• YAML or JSON

18. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Using AWS CloudFormation Export/ImportValue
Outputs:
WebServerSecurityGroup:
Description: Security group for public web servers
Value:
Fn::GetAtt:
- WebServerSecurityGroup
- GroupId
Export:
Name:
Fn::Sub: "${AWS::StackName}-SecurityGroupID”
PublicSubnet:
Description: Subnet for public web servers
Value:
Ref: PublicSubnet
Export:
Name:
Fn::Sub: "${AWS::StackName}-SubnetID"
Resources:
WebServerInstance:
Type: AWS::EC2::Instance
Properties:
InstanceType: t2.micro
ImageId: ami-a1b23456
NetworkInterfaces:
- GroupSet:
- Fn::ImportValue:
Fn::Sub: "${NetworkStackName}-SecurityGroupID"
AssociatePublicIpAddress: 'true'
DeviceIndex: '0'
DeleteOnTermination: 'true'
SubnetId:
Fn::ImportValue:
Fn::Sub: "${NetworkStackName}-SubnetID"
Stack A – Network Stack B – Web Servers
This is a Parameter

19. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
AWS Lambda Environment Variables
• Key-value pairs that you can dynamically pass to
your function
• Available via standard environment variable APIs
such as process.env for Node.js or os.environ for
Python
• Can optionally be encrypted via AWS Key
Management Service (KMS)
• Allows you to specify in IAM what roles have access to
the keys to decrypt the information
• Useful for creating environments per stage
(i.e. dev, testing, production)

20. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Amazon API Gateway Stage Variables
Stage variables act like environment variables
• Use stage variables to store configuration values
• Stage variables are available in the $context object
• Values are accessible from most fields
in API Gateway
• Lambda function ARN
• HTTP endpoint
• Custom authorizer function name
• Parameter mappings

21. AWS Lambda and Amazon API Gateway Variables + SAM
Parameters:
MyEnvironment:
Type: String
Default: test
AllowedValues:
- test
- staging
- prod
Description: Environment of this stack of
resources
Mappings:
SpecialFeature1:
test:
status: on
staging:
status: on
prod:
status: off
#Lambda
MyFunction:
Type: 'AWS::Serverless::Function'
Properties:
…
Environment:
Variables:
ENVIRONMENT: !Ref MyEnvironment
Spec_Feature1: !FindInMap [SpecialFeature1,
!Ref MyEnvironment, status]
…
#API Gateway
MyApiGatewayApi:
Type: AWS::Serverless::Api
Properties:
…
Variables:
ENVIRONMENT: !Ref MyEnvironment

22. Parameters:
MyEnvironment:
Type: String
Default: test
AllowedValues:
- test
- staging
- prod
Description: Environment of this stack of
resources
Mappings:
SpecialFeature1:
test:
status: on
staging:
status: on
prod:
status: off
#Lambda
MyFunction:
Type: 'AWS::Serverless::Function'
Properties:
…
Environment:
Variables:
ENVIRONMENT: !Ref MyEnvironment
Spec_Feature1: !FindInMap [SpecialFeature1,
!Ref MyEnvironment, status]
…
#API Gateway
MyApiGatewayApi:
Type: AWS::Serverless::Api
Properties:
…
Variables:
ENVIRONMENT: !Ref MyEnvironment
AWS Lambda and Amazon API Gateway Variables + SAM

23. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
MyLambdaFunction:
Type: AWS::Serverless::Function
Properties:
Handler: index.handler
Runtime: nodejs6.10
AutoPublishAlias: !Ref ENVIRONMENT
DeploymentPreference:
Type: Linear10PercentEvery10Minutes
Alarms:
# A list of alarms that you want to monitor
- !Ref AliasErrorMetricGreaterThanZeroAlarm
- !Ref LatestVersionErrorMetricGreaterThanZeroAlarm
Hooks:
# Validation Lambda functions that are run before & after traffic shifting
PreTraffic: !Ref PreTrafficLambdaFunction
PostTraffic: !Ref PostTrafficLambdaFunction
AWS SAM + Safe Deployments

24. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
AWS Lambda Alias Traffic Shifting & AWS SAM
AutoPublishAlias
By adding this property and specifying an
alias name, AWS SAM will do the
following:
• Detect when new code is being
deployed based on changes to the
Lambda function's Amazon S3 URI.
• Create and publish an updated version
of that function with the latest code.
• Create an alias with a name you
provide (unless an alias already exists)
and points to the updated version of
the Lambda function.
Deployment Preference Type
Canary10Percent30Minutes
Canary10Percent5Minutes
Canary10Percent10Minutes
Canary10Percent15Minutes
Linear10PercentEvery10Minutes
Linear10PercentEvery1Minute
Linear10PercentEvery2Minutes
Linear10PercentEvery3Minutes
AllAtOnce
In SAM:

25. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Alarms: # A list of alarms that you want to monitor
- !Ref AliasErrorMetricGreaterThanZeroAlarm
- !Ref LatestVersionErrorMetricGreaterThanZeroAlarm
Hooks: # Validation Lambda functions that are run before & after
traffic shifting
PreTraffic: !Ref PreTrafficLambdaFunction
PostTraffic: !Ref PostTrafficLambdaFunction
AWS Lambda Alias Traffic Shifting & AWS SAM
Note: You can specify a maximum of 10
alarms
In SAM:

26. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Globals:
Function:
Runtime: nodejs6.10
CodeUri: s3://code-artifacts/pet_app1234.zip
MemorySize: 1024
Timeout: 30
AutoPublishAlias: !Ref ENVIRONMENT
getDogsFunction:
Type: AWS::Serverless::Function
Properties:
Handler: getDogs.handler
Events:
GetDogs:
Type: Api
Properties:
Path: /Dogs
Method: ANY
getCatsFunction:
Type: AWS::Serverless::Function
Properties:
Handler: getCats.handler
Events:
GetCats:
Type: Api
Properties:
Path: /Cats
Method: ANY
getBirdsFunction:
Type: AWS::Serverless::Function
Properties:
Handler: getBirds.handler
Timeout: 15
Events:
GetBirds:
Type: Api
Properties:
Path: /Birds
Method: ANY
AWS SAM Globals

27. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Lambda permissions model
Fine grained security controls for both
execution and invocation:
Execution policies:
• Define what AWS resources/API calls can this
function access via IAM
• Used in streaming invocations
• E.g. “Lambda function A can read from
DynamoDB table users”
Function policies:
• Used for sync and async invocations
• E.g. “Actions on bucket X can invoke Lambda
function Z”
• Resource policies allow for cross account
configst access

28. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
AWS SAM Policy Templates
MyQueueFunction:
Type: AWS::Serverless::Function
Properties:
...
Policies:
# Gives permissions to poll an SQS Queue
- SQSPollerPolicy:
queueName: !Ref MyQueue
...
MyQueue:
Type: AWS::SQS::Queue
...

29. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
SAM Policy Templates
45+ predefined
policies
All found here:
https://bit.ly/2xWycnj

30. S U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.

31. Caroline Rennie
Product Lead
@cagsr89
medium.com/comic-relief

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43. • Identify limiting
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44. • Identify limiting
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45. • Identify limiting
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• Utilise rapid
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• Monitor to optimize

46. • Identify limiting
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S U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Danilo Poccia
@danilop
Caroline Rennie
@cagsr89