At AWS re:Invent, we have launched support for blue/green deployments for services hosted using AWS Fargate and Amazon Elastic Container Service (Amazon ECS). Blue/green deployments help you minimize downtime during application updates. They allow you to launch a new version of your application alongside the old version and test the new version before you reroute traffic to it. You can also monitor the deployment process and, if there is an issue, quickly roll back. In this workshop, you will create a new service in AWS Fargate that uses AWS CodeDeploy to manage the deployments, testing, and traffic cutover for you.

2. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Layers & Runtime API
Kwunhok Chan
Solutions Architect
Amazon Web Services

3. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.

4. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Agenda
Lambda Layers
Lambda Runtime API
Lamb

5. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.

6. Photo by Thibault Mokuenko on Unsplash
A way to centrally manage code and data
that is shared across multiple functions

7. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Layers Use Cases
• Custom code, that is used by more than one function
• Libraries, modules, frameworks to simplify the implementation of your
business logic

8. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Layers Benefits
• Enforce separation of concerns, between dependencies and your
custom business logic
• Make your function code smaller and more focused on what you want
to build
• Speed up deployments, because less code must be packaged and
uploaded, and dependencies can be reused

9. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Using Lambda Layers
• Put common components in a ZIP file and upload it as a Lambda Layer
• Layers can be versioned to manage updates
• Each version is immutable
• 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

10. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Using Lambda Layers
• In the configuration of a function, you can reference up to five layers
• One of which can optionally be a custom runtime
• When the function is invoked, layers are installed in the execution
environment in the order you provided
• The overall, uncompressed size of function and layers is subject to the usual unzipped
deployment package size limit (256MB)

11. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
How Lambda Layers Work
• Order is important because each layer is a ZIP file, and they are all
extracted in the same path
• /opt
• Each layer can potentially overwrite the previous one
• This approach can be used to customize the environment
• For example, the first layer can be a custom runtime and the second layer adds specific
versions of the libraries you need
• The storage of your Lambda Layers takes part in the AWS
Lambda Function storage per region limit (75GB)

12. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Including Library Dependencies in a Layer
Runtime Folders
Node.js
nodejs/node_modules
nodejs/node8/node_modules (NODE_PATH)
Python
python
python/lib/python3.7/site-packages (site directories)
Java java/lib (CLASSPATH)
Ruby
ruby/gems/2.5.0 (GEM_PATH)
ruby/lib (RUBY_LIB)
All
bin (PATH)
lib (LB_LIBRARY_PATH)

13. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Layers Permissions
• Layers can be used within
• An AWS account
• Shared between accounts
• Shared publicly with the broad developer community
• AWS is publishing a public layer which includes NumPy and SciPy, two
popular scientific libraries for Python
• This prebuilt and optimized layer can help you start very quickly with data processing and
machine learning applications

14. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Layers API
• Updated
• CreateFunction
• UpdateFunctionConfiguration
• New
• ListLayers
• ListLayerVersions
• PublishLayerVersion
• DeleteLayerVersion
• GetLayerVersion
• GetLayerVersionPolicy
• AddLayerVersionPermission
• RemoveLayerVersionPermission

15. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Layers in the AWS Serverless Application Model (SAM)
AWSTemplateFormatVersion: '2010-09-09’
Transform: AWS::Serverless-2016-10-31
Description: Sample SAM Template using Layers
Globals:
Function:
Timeout: 600
Resources:
OneLayerVersionServerlessFunction:
Type: AWS::Serverless::Function
Properties:
Handler: app.one_layer_hanlder
Runtime: python3.6
CodeUri: hello_world
Layers:
- <LayerOneVersionArn>
- <LayerTwoVersionArn>

16. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Layers in the AWS Serverless Application Model (SAM)
Resources:
MyLayer:
Type: AWS::Serverless::LayerVersion
Properties:
Description: Layer description
ContentUri: 's3://my-bucket/my-layer.zip’
CompatibleRuntimes:
- nodejs6.10
- nodejs8.10
LicenseInfo: 'Available under the MIT-0 license.’
RetentionPolicy: Retain

17. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.

18. Photo by Jeremy Lapak on Unsplash
A simple interface to use
any programming
language, or a specific
language version, for
developing your
functions

19. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Runtime API
• You can now select a custom runtime in the console (provided in the
API/SDKs/CLI) as the runtime of a Lambda function
• With this selection, the function must include (in its code or in a layer)
an executable file called bootstrap
• The runtime bootstrap is responsible for the communication between your code and the
Lambda environment
• Your code can use any programming language

20. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Runtime Boostrap
• The runtime bootstrap uses a simple HTTP based interface to
• get the event payload for a new invocation and
• return back the response from the function
• Information on the interface endpoint and the function handler are
shared as environment variables

21. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Using Custom Runtimes
• For the execution of your code, you can use anything that can run in
the Lambda execution environment.
• For example, you can bring an interpreter for the programming language of your choice.
• You only need to know how the Runtime API works if you want to
manage or publish your own runtimes
• As a developer, you can quickly use runtimes that are shared with you
as layers
• Custom runtimes can be shared as layers so that developers can pick them up and use their
favorite programming language when authoring Lambda functions

22. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Runtime API - Environment Variables
• AWS_LAMBDA_RUNTIME_API
• HOSTNAME:PORT
• _HANDLER
• SCRIPT_NAME.FUNCTION_NAME
• LAMBDA_TASK_ROOT
• The directory that contains the function code

23. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Runtime API - Processing Tasks
1. Get an event
2. Propagate tracing ID
3. Create a context object
4. Invoke the function handler
5. Handle the response
6. Handle errors
7. Cleanup

24. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Lambda Runtime API - Runtime Interactions
• POST /runtime/init/error
• GET /runtime/invocation/next
• The invocation-id is in the Lambda-Runtime-Aws-Request-Id header
• For AWS X-Ray there is a tracing header Lambda-Runtime-Trace-Id
• POST /runtime/invocation/{invocation-id}/response
• POST /runtime/invocation/{invocation-id}/error
• Sample Endpoint + Resource Path
• http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/next

25. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Open Source Runtimes
• C++ (AWS)
• Rust (AWS)
• Erlang (AlertLogic)
• Elixir (AlertLogic)
• Cobol (Blu Age)
• Node.js (NodeSource N|Solid)
• PHP (Stackery)
https://github.com/mthenw
/awesome-layers

26. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.

27. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
What we will be doing
• PHP
• Creating a PHP function
• Using Stackery layers
• Creating a Custom Runtime for… Bash functions!
• Bootstrap
• hello.sh
https://github.com/chankh/lambda-layers-workshop

28. Photo by Christoph Krichenbauer on Unsplash
What are you going to build?

29. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.

30. http://bit.ly/2REx0S6

31. Thank you!
© 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Kwunhok Chan
khchan@amazon.com
@kwunhok