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| 1 | +//! build: cargo build -p mcp-server-examples --example wasi_std_io --target wasm32-wasip1 |
| 2 | +//! |
| 3 | +//! run: npx @modelcontextprotocol/inspector wasmedge --dir logs:. run target/wasm32-wasip1/debug/examples/wasi_std_io.wasm |
| 4 | +//! |
| 5 | +use mcp_server::{router::RouterService, ByteTransport, Server}; |
| 6 | +use tracing_appender::rolling::{RollingFileAppender, Rotation}; |
| 7 | +use tracing_subscriber::EnvFilter; |
| 8 | +mod common; |
| 9 | +use anyhow::Result; |
| 10 | +use common::counter::CounterRouter; |
| 11 | +#[tokio::main(flavor = "current_thread")] |
| 12 | +async fn main() -> Result<()> { |
| 13 | + // Set up file appender for logging |
| 14 | + let file_appender = RollingFileAppender::new(Rotation::DAILY, "logs", "mcp-server.log"); |
| 15 | + |
| 16 | + // Initialize the tracing subscriber with file and stdout logging |
| 17 | + tracing_subscriber::fmt() |
| 18 | + .with_env_filter(EnvFilter::from_default_env().add_directive(tracing::Level::INFO.into())) |
| 19 | + .with_writer(file_appender) |
| 20 | + .with_target(false) |
| 21 | + .with_thread_ids(true) |
| 22 | + .with_file(true) |
| 23 | + .with_line_number(true) |
| 24 | + .init(); |
| 25 | + |
| 26 | + tracing::info!("Starting MCP server"); |
| 27 | + |
| 28 | + // Create an instance of our counter router |
| 29 | + let router = RouterService(CounterRouter::new()); |
| 30 | + |
| 31 | + // Create and run the server |
| 32 | + let server = Server::new(router); |
| 33 | + #[cfg(target_arch = "wasm32")] |
| 34 | + let transport = ByteTransport::new(async_io::WasiFd::std_in(), async_io::WasiFd::std_out()); |
| 35 | + #[cfg(not(target_arch = "wasm32"))] |
| 36 | + let transport = ByteTransport::new(tokio::io::stdin(), tokio::io::stdout()); |
| 37 | + |
| 38 | + tracing::info!("Server initialized and ready to handle requests"); |
| 39 | + Ok(server.run(transport).await?) |
| 40 | +} |
| 41 | + |
| 42 | +#[cfg(target_arch = "wasm32")] |
| 43 | +mod async_io { |
| 44 | + use tokio::io::{AsyncRead, AsyncWrite}; |
| 45 | + use wasi::{Fd, FD_STDIN, FD_STDOUT}; |
| 46 | + |
| 47 | + pub struct WasiFd { |
| 48 | + fd: Fd, |
| 49 | + } |
| 50 | + |
| 51 | + impl WasiFd { |
| 52 | + pub fn std_in() -> Self { |
| 53 | + Self { fd: FD_STDIN } |
| 54 | + } |
| 55 | + pub fn std_out() -> Self { |
| 56 | + Self { fd: FD_STDOUT } |
| 57 | + } |
| 58 | + } |
| 59 | + |
| 60 | + impl AsyncRead for WasiFd { |
| 61 | + fn poll_read( |
| 62 | + self: std::pin::Pin<&mut Self>, |
| 63 | + _cx: &mut std::task::Context<'_>, |
| 64 | + buf: &mut tokio::io::ReadBuf<'_>, |
| 65 | + ) -> std::task::Poll<std::io::Result<()>> { |
| 66 | + let mut temp_buf = vec![0u8; buf.remaining()]; |
| 67 | + unsafe { |
| 68 | + match wasi::fd_read( |
| 69 | + self.fd, |
| 70 | + &[wasi::Iovec { |
| 71 | + buf: temp_buf.as_mut_ptr(), |
| 72 | + buf_len: temp_buf.len(), |
| 73 | + }], |
| 74 | + ) { |
| 75 | + Ok(n) => { |
| 76 | + buf.put_slice(&temp_buf[..n]); |
| 77 | + std::task::Poll::Ready(Ok(())) |
| 78 | + } |
| 79 | + Err(err) => std::task::Poll::Ready(Err(std::io::Error::new( |
| 80 | + std::io::ErrorKind::Other, |
| 81 | + format!("WASI read error: {}", err), |
| 82 | + ))), |
| 83 | + } |
| 84 | + } |
| 85 | + } |
| 86 | + } |
| 87 | + |
| 88 | + impl AsyncWrite for WasiFd { |
| 89 | + fn poll_write( |
| 90 | + self: std::pin::Pin<&mut Self>, |
| 91 | + _cx: &mut std::task::Context<'_>, |
| 92 | + buf: &[u8], |
| 93 | + ) -> std::task::Poll<Result<usize, std::io::Error>> { |
| 94 | + unsafe { |
| 95 | + match wasi::fd_write( |
| 96 | + self.fd, |
| 97 | + &[wasi::Ciovec { |
| 98 | + buf: buf.as_ptr(), |
| 99 | + buf_len: buf.len(), |
| 100 | + }], |
| 101 | + ) { |
| 102 | + Ok(n) => std::task::Poll::Ready(Ok(n)), |
| 103 | + Err(err) => std::task::Poll::Ready(Err(std::io::Error::new( |
| 104 | + std::io::ErrorKind::Other, |
| 105 | + format!("WASI write error: {}", err), |
| 106 | + ))), |
| 107 | + } |
| 108 | + } |
| 109 | + } |
| 110 | + |
| 111 | + fn poll_flush( |
| 112 | + self: std::pin::Pin<&mut Self>, |
| 113 | + _cx: &mut std::task::Context<'_>, |
| 114 | + ) -> std::task::Poll<Result<(), std::io::Error>> { |
| 115 | + std::task::Poll::Ready(Ok(())) |
| 116 | + } |
| 117 | + |
| 118 | + fn poll_shutdown( |
| 119 | + self: std::pin::Pin<&mut Self>, |
| 120 | + cx: &mut std::task::Context<'_>, |
| 121 | + ) -> std::task::Poll<Result<(), std::io::Error>> { |
| 122 | + self.poll_flush(cx) |
| 123 | + } |
| 124 | + } |
| 125 | +} |
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