harbor

Harbor is a lightweight load balancer written in Rust. It is fun side-project to learn more about networking and load balancing. And also to learn Rust better. Not intended for production use.

This project does not use any external libraries for handling HTTP requests. It is built from scratch using the std::net and std::thread modules. I used httparse for parsing the HTTP requests.

Roadmap

Here are some of the features that I plan to implement in the future. As of now, I am focusing on the basic features and will add more features as I go along.

• Supports HTTP/1.1
• Add support for HTTP/2
• Add support for keep-alive connections
• Load balancing algorithms
  • Round-robin
  • Weighted round-robin
  • Least Active Connections
  • Random
  • Least Response Time
  • IP Hash
• Health checks for backend servers
• Configuration file support
• Logging

Usage

First of all, you will need to have Rust installed on your system. Then you could simply run the ./start.sh script to start the server. The server will start on localhost:8080 by default. This will also start a few backend servers on localhost:8081, localhost:8082 and localhost:8083.

You can pass a config file. Use environment variable HARBOR_CONFIG to specify the path to the config file. You can find an example config in the config.json file.

To test the load balancer performance (and how it performs under load), you can use the siege tool. Here is an example command to test the load balancer:

siege -t1M -c1000 -v http://0.0.0.0:8080

# -t1M: Run the test for 1 minute
# -c1000: Use 1000 concurrent connections
# -v: Verbose output

And this is how it performed on my machine (Ryzen 5/16GB RAM):

Lifting the server siege...
Transactions:		      173012 hits
Availability:		      100.00 %
Elapsed time:		       60.58 secs
Data transferred:	       25.29 MB
Response time:		        0.31 secs
Transaction rate:	     2855.93 trans/sec
Throughput:		        0.42 MB/sec
Concurrency:		      892.15
Successful transactions:      173013
Failed transactions:	           0
Longest transaction:	       54.73
Shortest transaction:	        0.00

License

This project is licensed under the MIT License - see the LICENSE file for details.

Check out Coding Challenges.