goose/crates/mcp-client/examples/clients.rs

use mcp_client::{
    client::{ClientCapabilities, ClientInfo, McpClient, McpClientTrait},
    transport::{SseTransport, StdioTransport, Transport},
};
use rand::Rng;
use rand::SeedableRng;
use std::time::Duration;
use std::{collections::HashMap, sync::Arc};
use tracing_subscriber::EnvFilter;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Initialize logging
    tracing_subscriber::fmt()
        .with_env_filter(
            EnvFilter::from_default_env().add_directive("mcp_client=debug".parse().unwrap()),
        )
        .init();

    let transport1 = StdioTransport::new("uvx", vec!["mcp-server-git".to_string()], HashMap::new());
    let handle1 = transport1.start().await?;
    let client1 = McpClient::connect(handle1, Duration::from_secs(30)).await?;

    let transport2 = StdioTransport::new("uvx", vec!["mcp-server-git".to_string()], HashMap::new());
    let handle2 = transport2.start().await?;
    let client2 = McpClient::connect(handle2, Duration::from_secs(30)).await?;

    let transport3 = SseTransport::new("http://localhost:8000/sse", HashMap::new());
    let handle3 = transport3.start().await?;
    let client3 = McpClient::connect(handle3, Duration::from_secs(10)).await?;

    // Initialize both clients
    let mut clients: Vec<Box<dyn McpClientTrait>> =
        vec![Box::new(client1), Box::new(client2), Box::new(client3)];

    // Initialize all clients
    for (i, client) in clients.iter_mut().enumerate() {
        let info = ClientInfo {
            name: format!("example-client-{}", i + 1),
            version: "1.0.0".to_string(),
        };
        let capabilities = ClientCapabilities::default();

        println!("\nInitializing client {}", i + 1);
        let init_result = client.initialize(info, capabilities).await?;
        println!("Client {} initialized: {:?}", i + 1, init_result);
    }

    // List tools for all clients
    for (i, client) in clients.iter_mut().enumerate() {
        let tools = client.list_tools(None).await?;
        println!("\nClient {} tools: {:?}", i + 1, tools);
    }

    println!("\n\n----------------------------------\n\n");

    // Wrap clients in Arc before spawning tasks
    let clients = Arc::new(clients);
    let mut handles = vec![];

    for i in 0..20 {
        let clients = Arc::clone(&clients);
        let handle = tokio::spawn(async move {
            // let mut rng = rand::thread_rng();
            let mut rng = rand::rngs::StdRng::from_entropy();
            tokio::time::sleep(Duration::from_millis(rng.gen_range(5..50))).await;

            // Randomly select an operation
            match rng.gen_range(0..4) {
                0 => {
                    println!("\n{i}: Listing tools for client 1 (stdio)");
                    match clients[0].list_tools(None).await {
                        Ok(tools) => {
                            println!("  {i}: -> Got tools, first one: {:?}", tools.tools.first())
                        }
                        Err(e) => println!("  {i}: -> Error: {}", e),
                    }
                }
                1 => {
                    println!("\n{i}: Calling tool for client 2 (stdio)");
                    match clients[1]
                        .call_tool("git_status", serde_json::json!({ "repo_path": "." }))
                        .await
                    {
                        Ok(result) => println!(
                            "  {i}: -> Tool execution result, is_error: {:?}",
                            result.is_error
                        ),
                        Err(e) => println!("  {i}: -> Error: {}", e),
                    }
                }
                2 => {
                    println!("\n{i}: Listing tools for client 3 (sse)");
                    match clients[2].list_tools(None).await {
                        Ok(tools) => {
                            println!("  {i}: -> Got tools, first one: {:?}", tools.tools.first())
                        }
                        Err(e) => println!("  {i}: -> Error: {}", e),
                    }
                }
                3 => {
                    println!("\n{i}: Calling tool for client 3 (sse)");
                    match clients[2]
                            .call_tool(
                                "echo_tool",
                                serde_json::json!({ "message": "Client with SSE transport - calling a tool" }),
                            )
                            .await
                        {
                        Ok(result) => println!("  {i}: -> Tool execution result, is_error: {:?}", result.is_error),
                        Err(e) => println!("  {i}: -> Error: {}", e),
                    }
                }
                _ => unreachable!(),
            }
            Ok::<(), Box<dyn std::error::Error + Send + Sync>>(())
        });
        handles.push(handle);
    }

    // Wait for all tasks to complete
    for handle in handles {
        handle.await.unwrap().unwrap();
    }

    Ok(())
}