July 2021 Summaries

In this tutorial, we create a simple retrospective app using .NET 5 and Ably's pub/sub service. The application is divided into three services: Facade, Topic, and Notification. Each service has its own responsibilities, such as showing information to clients (Facade), saving retrospective topics to a database (Topic), and collecting notifications from other services (Notification). The code for each service is written in .NET 5 (C# or F#) and uses Ably's pub/sub service for communication between the services. We also use MongoDB as a data store, OpenAPI documentation, and health checks for each service. The frontend part of the app is written in Angular 8. The architecture diagram shows how the three services communicate with each other via Ably's pub/sub channels. We use an out-of-the-box pub/sub service like Ably to simplify the communication between services and clients. Ably provides several services, including pub/sub, message persistence history, push notifications for mobile apps, and more. It also has a .NET library ready to use. The main terms used in Ably are Channels and Message Types. The code examples provided show how the Facade service receives requests from clients and directs them to other services. We also see how the Topic service saves retrospective topics to MongoDB and notifies clients about handled topics, as well as how the Notification service handles messages and forwards them to all interested clients/services. Finally, we run the whole app using docker-compose up since the docker-compose file is in place. This tutorial demonstrates how to build a realtime full stack app with .NET, Angular, MongoDB, and Ably.

Ably's new Control API allows DevOps engineers working on fast-scaling software architectures to increase their testing capabilities and configure complex production systems quickly and safely, directly from configuration and orchestration tools. The Control API is a REST API that enables programmatic management of Ably’s configuration, allowing users to create, configure, and delete apps, API keys, channel rules/namespaces, queues, and stats. This feature helps save time and avoid potential errors resulting from manual configurations. It also supports driving CI/CD pipelines with Ably apps, ensuring audit trace and easy configuration recovery, and scaling automatically with the needs of a business.

This post discusses implementing low-level WebSockets libraries with Node.js as the WebSocket server. It covers WS, a WebSocket server for Node.js, and SockJS, which mimics the native WebSocket API and falls back to HTTP when necessary. The post also explores scaling challenges with WebSockets and how third-party services like Ably can help manage these issues.

At Ably, we run a large-scale production infrastructure that powers our customers' real-time messaging applications worldwide using Docker containers. Despite Kubernetes being the most widely known system for orchestrating containerized software, we do not currently use it nor plan to in the near future. Our current setup involves running on EC2 instances and leveraging AWS services like Network Load Balancers and CloudFront for traffic ingress. We believe that introducing Kubernetes would merely move some of our problems around instead of actually solving them. While Kubernetes has its benefits, such as resource management and traffic ingress, it also comes with added costs and complexity. For now, we are focusing on improving other aspects of our infrastructure to ensure reliability, low latency, and high availability for our users.

Web Components are a collection of web technologies that enable developers to create reusable pieces of markup and functionality for the browser, independent of any runtime framework. They consist of Custom Elements, Shadow DOM, and HTML templates. In this article, we delve into building a chat web component with Ably using AWS Amplify and AWS Lambda. The process involves creating two Custom Elements: AblyBaseComponent and AblyChatComponent. We also discuss API key management and hosting the application on Amplify.