Go Load Balancer with Configurable Algorithms and External Server Configuration

This Go project implements a load balancer that supports two balancing methods: Round Robin (rr) and Weighted Round Robin (wrr). It allows you to spawn local servers or read external server addresses from a configuration file (.json or .yaml) via a flag.

Features

• Round Robin (rr) and Weighted Round Robin (wrr) algorithms for load balancing.
• Support for local server spawning or external server configuration via .json or .yaml files.
• Configurable via command-line flags.

Command-Line Flags

• -amount: Number of local servers to spawn (used only with -env local). Default is 1234.
• -method: Load balancing method. Choose between:
  • rr: Round Robin.
  • wrr: Weighted Round Robin.
• -env: Environment setting. Choose between:
  • local: Spawns the specified amount of local servers.
  • external: Reads server addresses from an external file (provided via -path flag).
• -path: Specifies the path to the external .json or .yaml configuration file (used with -env external).
• -healthCheck: Runs health check on external servers provided within a configuration file (used with -path).
• -port: Specifies port used to run load balancer service.
• -srv-port: Specifies port used to run local servers for testing purposes.

Example Usage

1.Spawn Local Servers (5 servers, round-robin method):

go run *.go -amount 5 -method rr -env local

Use External Servers from a JSON File (weighted round-robin method):

go run *.go -method wrr -env external -path ./servers.json

Use External Servers from a YAML File (round-robin method):

go run *.go -method rr -env external -path ./servers.yaml

Configuration File Format

When using the -env external flag, the load balancer will read server information from a configuration file. You can provide the file in either YAML or JSON format.

Sample YAML Configuration (servers.yaml)

---
- addr: https://facebook.com
  weight: 2
- addr: https://twitch.tv
  weight: 1
- addr: https://google.com
  weight: 3

Sample JSON Configuration (servers.json)

[
  {
    "addr": "https://facebook.com",
    "weight": 2
  },
  {
    "addr": "https://twitch.tv",
    "weight": 1
  },
  {
    "addr": "https://google.com",
    "weight": 3
  }
]

How It Works

Load Balancing Methods

Round Robin (rr): Distributes requests evenly across all available servers. Weighted Round Robin (wrr): Distributes requests based on the weight assigned to each server. Servers with higher weights receive more traffic. Local Server Spawning When using -env local, the program spawns a number of local servers on ports starting from 8000 (e.g., localhost:8000, localhost:8001, etc.).

External Servers

When using -env external with the -path flag, the load balancer reads external server addresses from the specified JSON or YAML file and balances requests accordingly.

Example Output

Example output when running with 3 local servers:

serving requests at localhost:7000
forwarding to "localhost:8000"
forwarding to "localhost:8001"
forwarding to "localhost:8002"

Example output when using an external JSON configuration:

serving requests at localhost:7000
forwarding to "https://facebook.com"
forwarding to "https://twitch.tv"
forwarding to "https://google.com"

Port flag

We can pass -srv-port flag to specify port for local servers and -port flag to specify port for load balancer

./lb -srv-port 8000 -port 7000 

Health check

We are able to run health check on external servers listed in the config file

./lb -healthCheck -path ./servers.yaml

License

This project is open-source and available under the MIT License.