AWS Lambda Extension / Sidecar Container

Diagram cache server

Cache Server

The cache server is written in Golang and it uses the same code to run inside a lambda extension and to run the sidecar container. To be able to run the same extension in different lambda’s runtime, we needed a language that could generate a binary in the end, so we are able to execute the binary directly without caring about the lambda runtime language/version.

The server runs on port 8015 and receives the secret name and the refresh parameters. The refresh parameter is used to invalidate the cache.

How it works

Lambda Extension

Sequence Diagram lambda

Sidecar Container

Diagram cache server

Use Case

Use the cache server to retreive database password to connect to the database in different Lambda Runtimes.

Laravel Aurora Connector (https://github.com/cgauge/laravel-aurora-connector) library use this strategy.

Some implementation details can be found here: https://github.com/cgauge/laravel-aurora-connector/blob/main/src/PasswordResolver.php

Usage

Lambda Extension

# CloudFormation
AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Resources:
  function:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs12.x
      CodeUri: function/.
      Layers:
        - arn:aws:lambda:eu-west-1:12345678:layer:secretsmanager-caching-extension:1

# Serverless Framework
functions:
  hello:
    handler: handler.hello
    layers:
        - arn:aws:lambda:eu-west-1:12345678:layer:secretsmanager-caching-extension:1

Sidecar Container

# Cloudformation
TaskDefinition:
  Type: 'AWS::ECS::TaskDefinition'
  Properties:
    ContainerDefinitions:
      - Name: Name of your service image
        Image: your.service.image/tag:version
        PortMappings:
          - ContainerPort: '80'
            
      - Name: CacheSecretsService
        Image: customergauge/aws-secretsmanager-caching-sidecar
        PortMappings:
          - ContainerPort: '8015'
    ...

Contributing

Contributions are always welcome, please have a look at our issues to see if there’s something you could help with.

License

AWS Secrets Manager Caching Extension is licensed under LGPLv3 license.

GitHub

View Github