The Nugget
- Deno's
servecommand is evolving to support parallelism, allowing for improved performance and CPU utilization by handling multiple requests simultaneously rather than sequentially. This shift aims to enhance the "magical" feeling of Deno Serve, making it more useful and efficient for users.
Make it stick
- ⚙️ The declarative HTTP API allows users to simply export a fetch function, making server setup easier.
- 🛠️ Current options like the Node cluster module allow for load balancing but are not currently compatible with Deno.
- 🚀 The initial MVP implementation uses the
reusePortoption on Linux for efficient load balancing across workers. - 🌐 Future plans include improving load balancing by having a primary worker accept connections and distribute them effectively to worker threads.
Key insights
Design and Purpose of Deno Serve
- Deno Serve was created to offer a simple, declarative HTTP API for building web servers.
- Initially influenced by the API of Cloudflare Workers, it aims to simplify server management for users who might not be familiar with Deno.
- The goal is to reduce complexity and abstract away mundane details, enhancing user experience.
Need for Parallelism in Deno Serve
- Concurrency vs Parallelism:
- JavaScript's concurrency is not the same as true parallelism, meaning it can't utilize multiple CPU cores effectively with single-threaded execution.
- Benefits of Parallelism:
- Parallelism allows for utilizing full CPU capabilities, leading to significant performance improvements.
- The current implementation sees about 5x performance boost on existing repositories due to multiprocess support.
Current Implementation Options
- Options for parallelism in Deno serve currently include:
- Node Cluster Module:
- Spawns child processes for handling requests but requires manual orchestration and is not compatible with Deno.
- PM2 Process Manager:
- Sits on top of the Node cluster but, like Node’s approach, is not implemented in Deno.
- Reuse Port Option:
- Available only on Linux for load balancing but does not have formal support on Mac and Windows.
Future Enhancements
- Proposed enhancements for Deno Serve include:
- Single Worker for Connection Handling:
- One thread will manage incoming connections while distributing requests to worker threads, ideally through a round-robin method.
- User Control Options:
- Plans to implement a more manual API for users who want to customize their parallel setups.
- Failure Management:
- Options for different responses in failure scenarios, such as not crashing the whole server when one worker fails.
- Single Worker for Connection Handling:
Key quotes
- "Deno Serve aims to provide a magical experience by minimizing the boring parts of server management."
- "JavaScript does well with concurrency, but it's the lack of true parallelism that limits CPU utilization."
- "Current implementations struggle with evenly distributing load across platforms, particularly Mac and Windows."
- "In the future, we want each worker to handle connections more intelligently and to offer users more control over their setups."
- "Our current MVP provides about a five times performance boost on supported repositories."
This summary contains AI-generated information and may have important inaccuracies or omissions.