RapidClient

A simple HTTP client tool that forces source port reuse by bypassing TIME_WAIT state, designed for testing Maglev consistent hashing and load balancer behavior.

Features

Source Port Reuse: Forces connections to use a specific source port, bypassing TIME_WAIT
New TCP Connection: Each call establishes a fresh TCP connection (no connection reuse)
Socket Options: Sets SO_REUSEADDR for rapid port reuse
Simple Output: Sends a single request and prints the raw response
Configurable: Command-line options for URL, source port, and timeout

Usage

Docker Run

bash

# Basic Docker usage with host networking
docker run --rm --network host rapidclient:latest -url "http://10.103.218.83:8080/shell?cmd=hostname"

# With verbose output
docker run --rm --network host rapidclient:latest -url "http://10.103.218.83:8080/shell?cmd=hostname" -v

# With custom source port
docker run --rm --network host rapidclient:latest -url "http://10.103.218.83:8080/shell?cmd=hostname" -port 54321

# With custom timeout
docker run --rm --network host rapidclient:latest -url "http://10.103.218.83:8080/shell?cmd=hostname" -timeout 10s

Basic Usage

bash

# Send a single request to a service
./rapidclient -url "http://10.96.0.1:8080/shell?cmd=hostname"

# Use a specific source port
./rapidclient -url "http://10.96.0.1:8080/shell?cmd=hostname" -port 12345

# Verbose output with status information
./rapidclient -url "http://10.96.0.1:8080/shell?cmd=hostname" -v

Command Line Options

-url string: Target URL to send request to (required)
-port int: Source port to use for connection (default: 12345)
-timeout duration: Request timeout (default: 30s)
-v: Verbose logging (shows status and debug info)

Examples

bash

# Test Maglev load balancing with consistent source port
./rapidclient -url "http://service-ip:8080/shell?cmd=hostname" -port 12345

# Test with custom timeout
./rapidclient -url "http://service-ip:8080/api/health" -timeout 10s

# Verbose mode for debugging
./rapidclient -url "http://service-ip:8080/shell?cmd=hostname" -port 12345 -v

Technical Details

Uses SO_REUSEADDR socket option to allow rapid port reuse
Disables HTTP keep-alive to force new connections
Custom dialer with specific source port binding
Handles both IPv4 and IPv6 connections

Output

Normal Mode

bash

$ ./rapidclient -url "http://10.96.0.1:8080/shell?cmd=hostname"
{"output":"backend-pod-5\n"}

Verbose Mode

bash

$ ./rapidclient -url "http://10.96.0.1:8080/shell?cmd=hostname" -v
2025/09/04 10:30:00 Sending request to: http://10.96.0.1:8080/shell?cmd=hostname
2025/09/04 10:30:00 Using source port: 12345
2025/09/04 10:30:00 Timeout: 30s
Status: 200 OK
Response: {"output":"backend-pod-5\n"}

Integration with Tests

This tool can replace curl commands in tests for better reliability:

bash

# Instead of:
curl --local-port 12345 -s http://service:8080/shell?cmd=hostname

# Use:
./rapidclient -url "http://service:8080/shell?cmd=hostname" -port 12345