feat(server): support wasm32-wasi

Support the `wasm32-wasi` target, disabling unsupported components.

Signed-off-by: Richard Zak <[email protected]>

Cargo.toml

@@ -28,18 +28,22 @@ http = "0.2"
 http-body = "0.4"
 httpdate = "1.0"
 httparse = "1.6"
-h2 = { version = "0.3.9", optional = true }
+# h2 = { version = "0.3.9", optional = true }
+h2 = { git = "https://github.com/rjzak/h2", branch = "wasi_wip", optional = true }
 itoa = "1"
 tracing = { version = "0.1", default-features = false, features = ["std"] }
 pin-project-lite = "0.2.4"
 tower-service = "0.3"
-tokio = { version = "1", features = ["sync"] }
+# tokio = { version = "1", features = ["sync"] }
+tokio = { git = "https://github.com/rjzak/tokio", branch = "wasi_wip", features = ["sync"] }
 want = "0.3"
 
 # Optional
 
 libc = { version = "0.2", optional = true }
-socket2 = { version = "0.4", optional = true }
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+socket2 = { version = "0.4" }
 
 [dev-dependencies]
 futures-util = { version = "0.3", default-features = false, features = ["alloc"] }
@@ -49,7 +53,8 @@ pretty_env_logger = "0.4"
 spmc = "0.3"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-tokio = { version = "1", features = [
+# tokio = { version = "1", features = [
+tokio = { git = "https://github.com/rjzak/tokio", branch = "wasi_wip", features = [
     "fs",
     "macros",
     "io-std",
@@ -61,7 +66,8 @@ tokio = { version = "1", features = [
     "test-util",
 ] }
 tokio-test = "0.4"
-tokio-util = { version = "0.7", features = ["codec"] }
+# tokio-util = { version = "0.7", features = ["codec"] }
+tokio-util = { git = "https://github.com/rjzak/tokio", branch = "wasi_wip", features = ["codec"] }
 tower = { version = "0.4", features = ["make", "util"] }
 url = "2.2"
 
@@ -100,7 +106,6 @@ runtime = [
     "tokio/time",
 ]
 tcp = [
-    "socket2",
     "tokio/net",
     "tokio/rt",
     "tokio/time",

src/server/server.rs

@@ -72,6 +72,7 @@ impl Server<AddrIncoming, ()> {
     ///
     /// This method will panic if binding to the address fails. For a method
     /// to bind to an address and return a `Result`, see `Server::try_bind`.
+    #[cfg(not(target_os = "wasi"))]
     pub fn bind(addr: &SocketAddr) -> Builder<AddrIncoming> {
         let incoming = AddrIncoming::new(addr).unwrap_or_else(|e| {
             panic!("error binding to {}: {}", addr, e);
@@ -80,6 +81,7 @@ impl Server<AddrIncoming, ()> {
     }
 
     /// Tries to bind to the provided address, and returns a [`Builder`](Builder).
+    #[cfg(not(target_os = "wasi"))]
     pub fn try_bind(addr: &SocketAddr) -> crate::Result<Builder<AddrIncoming>> {
         AddrIncoming::new(addr).map(Server::builder)
     }

src/server/tcp.rs

@@ -3,6 +3,9 @@ use std::io;
 use std::net::{SocketAddr, TcpListener as StdTcpListener};
 use std::time::Duration;
 
+#[cfg(target_os = "wasi")]
+use std::net::{IpAddr, Ipv4Addr};
+
 use tokio::net::TcpListener;
 use tokio::time::Sleep;
 use tracing::{debug, error, trace};
@@ -25,6 +28,7 @@ pub struct AddrIncoming {
 }
 
 impl AddrIncoming {
+    #[cfg(not(target_os = "wasi"))]
     pub(super) fn new(addr: &SocketAddr) -> crate::Result<Self> {
         let std_listener = StdTcpListener::bind(addr).map_err(crate::Error::new_listen)?;
 
@@ -41,13 +45,21 @@ impl AddrIncoming {
     }
 
     /// Creates a new `AddrIncoming` binding to provided socket address.
+    #[cfg(not(target_os = "wasi"))]
     pub fn bind(addr: &SocketAddr) -> crate::Result<Self> {
         AddrIncoming::new(addr)
     }
 
     /// Creates a new `AddrIncoming` from an existing `tokio::net::TcpListener`.
+    /// For target `wasm32-wasi`, the assumed local address is "0.0.0.0:0", since
+    /// WebAssembly-Wasi has no way to know the local address used for listening.
+    /// This could be removed, but would require refactoring a lot of code in Hyper,
+    /// and other downstream projects.
     pub fn from_listener(listener: TcpListener) -> crate::Result<Self> {
+        #[cfg(not(target_os = "wasi"))]
         let addr = listener.local_addr().map_err(crate::Error::new_listen)?;
+        #[cfg(target_os = "wasi")]
+        let addr = SocketAddr::new(IpAddr::V4(Ipv4Addr::UNSPECIFIED), 0);
         Ok(AddrIncoming {
             listener,
             addr,
@@ -108,18 +120,26 @@ impl AddrIncoming {
         loop {
             match ready!(self.listener.poll_accept(cx)) {
                 Ok((socket, remote_addr)) => {
-                    if let Some(dur) = self.tcp_keepalive_timeout {
-                        let socket = socket2::SockRef::from(&socket);
-                        let conf = socket2::TcpKeepalive::new().with_time(dur);
-                        if let Err(e) = socket.set_tcp_keepalive(&conf) {
-                            trace!("error trying to set TCP keepalive: {}", e);
+                    #[cfg(not(target_os = "wasi"))]
+                    {
+                        if let Some(dur) = self.tcp_keepalive_timeout {
+                            let socket = socket2::SockRef::from(&socket);
+                            let conf = socket2::TcpKeepalive::new().with_time(dur);
+                            if let Err(e) = socket.set_tcp_keepalive(&conf) {
+                                trace!("error trying to set TCP keepalive: {}", e);
+                            }
                         }
+                        if let Err(e) = socket.set_nodelay(self.tcp_nodelay) {
+                            trace!("error trying to set TCP nodelay: {}", e);
+                        }
+                        let local_addr = socket.local_addr()?;
+                        return Poll::Ready(Ok(AddrStream::new(socket, remote_addr, local_addr)));
                     }
-                    if let Err(e) = socket.set_nodelay(self.tcp_nodelay) {
-                        trace!("error trying to set TCP nodelay: {}", e);
+                    #[cfg(target_os = "wasi")]
+                    {
+                        let local_addr = SocketAddr::new(IpAddr::V4(Ipv4Addr::UNSPECIFIED), 0);
+                        return Poll::Ready(Ok(AddrStream::new(socket, remote_addr, local_addr)));
                     }
-                    let local_addr = socket.local_addr()?;
-                    return Poll::Ready(Ok(AddrStream::new(socket, remote_addr, local_addr)));
                 }
                 Err(e) => {
                     // Connection errors can be ignored directly, continue by
@@ -199,6 +219,8 @@ mod addr_stream {
     use std::net::SocketAddr;
     #[cfg(unix)]
     use std::os::unix::io::{AsRawFd, RawFd};
+    #[cfg(target_os = "wasi")]
+    use std::os::wasi::io::{AsRawFd, RawFd};
     use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
     use tokio::net::TcpStream;
 
@@ -309,7 +331,7 @@ mod addr_stream {
         }
     }
 
-    #[cfg(unix)]
+    #[cfg(any(unix, target_os = "wasi"))]
     impl AsRawFd for AddrStream {
         fn as_raw_fd(&self) -> RawFd {
             self.inner.as_raw_fd()