Post summary: Overview of the AWS examples in C# series.
In several blog posts, I give some practical examples of how to use AWS SQS, DynamoDB, Lambda with C# code. The code used for this series of blog posts is located in aws.examples.csharp GitHub repository.
Introduction
AWS stands for Amazon Web Services, it is a subsidiary of Amazon that provides on-demand cloud computing platforms and APIs to individuals, companies, and governments, on a metered pay-as-you-go basis. AWS is one of the big cloud service providers. The others are Microsoft Azure and Google Cloud. All three cloud service providers have functions that are semantically common but differ in practical implementation. Also, every one of them has its own flavors. I have chosen to use AWS for these examples as it is something I have used before and I am most comfortable with it.
Architectural overview
In order to get a full understanding of the architecture, I have prepared this very basic diagram. It illustrates what services are there and how they communicate. 
SqsReader and SqsWriter
Both are .NET Core 3.0 microservices running in docker containers. The images are uploaded in AWS ECR (Elastic Container Registry) and containers are run in AWS ECS (Elastic Container Service). SqsReader has a REST endpoint, by which an Actor or Movie can be posted. Both are pushed as a message to AWS SQS (Simple Queue Service). SqsWriter is listening to the SQS and in case of a message, it processes it. If the message is from type Actor or Movie then SqsReader saves it to the respective AWS DynamoDB tables. If the message is LogEntry, then the message is only output into SqsReader logs.
ActorsLambdaFunction and MoviessLambdaFunction
Both are .NET Core 2.1 lambda functions run in AWS Lambda. They listen to Actors and Movies DynamoDB tables changes and in case of new entries, they write to LogEntries DynamoDB table. Also, they write SQS messages from type LogEntry, which are then read by SqsReader.
ActorsServerlessLambda and MoviesServerlessLambda
Those are again lambda functions by are fully managed by the Serverless framework. They have a lambda application defined as well as Cloud Formation templates. They expose a REST API trough AWS API Gateway, by which the Actors table can be queried or a movie can be got from the Movies table.
Post in the series
This is a long series of posts describing into detail all the pieces of the architectural diagram above. Also, every aspect of the code in the repository is explained in detail in subsequent blog posts. It was a very interesting learning opportunity for me, which I would like to share. Here are the posts in the series:
- AWS examples in C# – run the solution
- AWS examples in C# – basic SQS queue operations
- AWS examples in C# – create a service working with SQS
- AWS examples in C# – basic DynamoDB operations
- AWS examples in C# – create a service working with DynamoDB
- AWS examples in C# – working with Lambda functions
- AWS examples in C# – create basic Lambda function
- AWS examples in C# – introduction to Serverless framework
- AWS examples in C# – AWS CLI commands
- AWS examples in C# – structured logging in .NET Core and AWS Lambda
Future plans
There are several topics I would like to go into as well, but there is no code yet for them into the GitHub repository. Those are:
- AWS examples in C# – manage with Terraform
- AWS examples in C# – use AWS Cognito for API Gateway authorizer
Conclusion
These series of posts are intended to give some basic overview of important AWS services and how to use them in C# code.
