sandaruwan98/toxiproxy-mcp-server

Toxiproxy MCP Server

A Model Context Protocol (MCP) server for managing Toxiproxy proxies to simulate network conditions in testing environments.

Overview

This MCP server provides tools to:

• Create proxies for PostgreSQL and RabbitMQ databases
• Add various toxics (latency, bandwidth, timeout) to simulate network issues
• Manage proxy lifecycle and port forwarding rules
• Reset and clean up testing environments

Prerequisites

1. Start Toxiproxy Server (required before using this MCP server):

   docker run --rm -it \
     --network=host \
     --add-host=dev.localhost:127.0.0.1 \
     ghcr.io/shopify/toxiproxy:2.5.0 -host 0.0.0.0
   

2. Build the MCP Server:

   npm install
   npm run build
   

Available Tools

1. check_toxiproxy_status

Check if the Toxiproxy server is running and accessible.

2. create_db_proxy

Create a PostgreSQL database proxy.

• Parameters: name, dbPort, proxyPort (optional), upstream (optional)
• Example: Create proxy for database on port 15234

3. create_rabbitmq_proxy

Create a RabbitMQ proxy.

• Parameters: name, amqpPort (optional, defaults to 5672), proxyPort (optional), upstream (optional)

4. add_latency_toxic

Add latency simulation to a proxy.

• Parameters: proxyName, latency (ms), jitter (optional), toxicity (optional), direction (optional)
• Example: Add 2000ms latency with 100ms jitter

5. add_bandwidth_toxic

Add bandwidth limiting to a proxy.

• Parameters: proxyName, rate (KB/s), toxicity (optional), direction (optional)

6. add_timeout_toxic

Add timeout simulation to a proxy.

• Parameters: proxyName, timeout (ms), toxicity (optional), direction (optional)

7. list_proxies

List all active proxies and their toxics.

8. remove_toxic

Remove a specific toxic from a proxy.

• Parameters: proxyName, toxicName

9. delete_proxy

Delete a proxy entirely.

• Parameters: proxyName

10. reset_proxies

Reset all proxies (remove all toxics and enable all proxies).

Usage Workflow

1. Start Toxiproxy server (see prerequisites)
2. Check status: check_toxiproxy_status
3. Create proxy: create_db_proxy with your database port
4. Run the iptables command provided by the tool (requires sudo)
5. Add toxics: Use add_latency_toxic, add_bandwidth_toxic, etc.
6. Test your application - it should now experience the simulated network conditions
7. Clean up: Use remove_toxic, delete_proxy, or reset_proxies

Example Session

# 1. Check if Toxiproxy is running
check_toxiproxy_status

# 2. Create a database proxy for PostgreSQL on port 15234
create_db_proxy name="postgres_proxy" dbPort=15234

# 3. Run the iptables command shown in the output (with sudo)
sudo iptables -t nat -A PREROUTING -p tcp --dport 15234 -j REDIRECT --to-port 25234

# 4. Add latency toxic
add_latency_toxic proxyName="postgres_proxy" latency=2000 jitter=100

# 5. Your application will now experience 2s latency when connecting to the database

# 6. List all proxies to see current state
list_proxies

# 7. Clean up when done
reset_proxies

Port Forwarding

The MCP server generates iptables commands for you to run manually. This approach:

• Gives you visibility into what network changes are being made
• Avoids requiring the MCP server to run with sudo privileges
• Allows you to manage and remove rules as needed

To add a rule: Copy and run the command provided by create_db_proxy or create_rabbitmq_proxy To remove a rule: Use the removal command also provided, or list rules with:

sudo iptables -t nat -L PREROUTING --line-numbers
sudo iptables -t nat -D PREROUTING <line_number>

Troubleshooting

• "Cannot connect to Toxiproxy server": Make sure the Docker container is running on port 8474
• "Proxy not found": Check the proxy name and use list_proxies to see available proxies
• Network traffic not being intercepted: Verify the iptables rule was applied correctly
• Permission denied for iptables: The commands need to be run with sudo

License

ISC# toxiproxy-mcp-server