add tcp-p3 example and test

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

Author: rvolosatovs

.gitignore

@@ -12,6 +12,7 @@ examples/http/.spin
 examples/http/http.wasm
 examples/http/proxy
 examples/http/poll_loop.py
+examples/tcp-p3/tcp.wasm
 examples/tcp/tcp.wasm
 examples/tcp/command
 examples/cli-p3/cli.wasm

examples/tcp-p3/README.md

@@ -0,0 +1,45 @@
+# Example: `tcp-p3`
+
+This is an example of how to use [componentize-py] and [Wasmtime] to build and
+run a Python-based component targetting version `0.3.0-rc-2026-01-06` of the
+[wasi-cli] `command` world and making an outbound TCP request using [wasi-sockets].
+
+[componentize-py]: https://github.com/bytecodealliance/componentize-py
+[Wasmtime]: https://github.com/bytecodealliance/wasmtime
+[wasi-cli]: https://github.com/WebAssembly/WASI/tree/v0.3.0-rc-2026-01-06/proposals/cli/wit-0.3.0-draft
+[wasi-sockets]: https://github.com/WebAssembly/WASI/tree/v0.3.0-rc-2026-01-06/proposals/sockets/wit-0.3.0-draft
+
+## Prerequisites
+
+* `Wasmtime` 41.0.3
+* `componentize-py` 0.21.0
+
+Below, we use [Rust](https://rustup.rs/)'s `cargo` to install `Wasmtime`.  If
+you don't have `cargo`, you can download and install from
+https://github.com/bytecodealliance/wasmtime/releases/tag/v41.0.3.
+
+```
+cargo install --version 41.0.3 wasmtime-cli
+pip install componentize-py==0.21.0
+```
+
+## Running the demo
+
+First, in a separate terminal, run `netcat`, telling it to listen for incoming
+TCP connections.  You can choose any port you like.
+
+```
+nc -l 127.0.0.1 3456
+```
+
+Now, build and run the example, using the same port you gave to `netcat`.
+
+```
+componentize-py -d ../../wit -w wasi:cli/command@0.3.0-rc-2026-01-06 componentize app -o tcp.wasm
+wasmtime run -Sp3 -Sinherit-network -Wcomponent-model-async tcp.wasm 127.0.0.1:3456
+```
+
+The program will open a TCP connection, send a message, and wait to receive a
+response before exiting.  You can give it a response by typing anything you like
+into the terminal where `netcat` is running and then pressing the `Enter` key on
+your keyboard.

examples/tcp-p3/app.py

@@ -0,0 +1,81 @@
+import sys
+import asyncio
+import ipaddress
+from ipaddress import IPv4Address, IPv6Address
+import wit_world
+from wit_world import exports
+from wit_world.imports.wasi_sockets_types import (
+    TcpSocket,
+    IpSocketAddress_Ipv4,
+    IpSocketAddress_Ipv6,
+    Ipv4SocketAddress,
+    Ipv6SocketAddress,
+    IpAddressFamily,
+)
+from typing import Tuple
+
+
+IPAddress = IPv4Address | IPv6Address
+
+class Run(exports.Run):
+    async def run(self) -> None:
+        args = sys.argv[1:]
+        if len(args) != 1:
+            print("usage: tcp-p3 <address>:<port>", file=sys.stderr)
+            exit(-1)
+
+        address, port = parse_address_and_port(args[0])
+        await send_and_receive(address, port)
+
+
+def parse_address_and_port(address_and_port: str) -> Tuple[IPAddress, int]:
+    ip, separator, port = address_and_port.rpartition(":")
+    assert separator
+    return (ipaddress.ip_address(ip.strip("[]")), int(port))
+
+
+def make_socket_address(address: IPAddress, port: int) -> IpSocketAddress_Ipv4 | IpSocketAddress_Ipv6:
+    if isinstance(address, IPv4Address):
+        octets = address.packed
+        return IpSocketAddress_Ipv4(Ipv4SocketAddress(
+            port=port,
+            address=(octets[0], octets[1], octets[2], octets[3]),
+        ))
+    else:
+        b = address.packed
+        return IpSocketAddress_Ipv6(Ipv6SocketAddress(
+            port=port,
+            flow_info=0,
+            address=(
+                (b[0] << 8) | b[1],
+                (b[2] << 8) | b[3],
+                (b[4] << 8) | b[5],
+                (b[6] << 8) | b[7],
+                (b[8] << 8) | b[9],
+                (b[10] << 8) | b[11],
+                (b[12] << 8) | b[13],
+                (b[14] << 8) | b[15],
+            ),
+            scope_id=0,
+        ))
+
+
+async def send_and_receive(address: IPAddress, port: int) -> None:
+    family = IpAddressFamily.IPV4 if isinstance(address, IPv4Address) else IpAddressFamily.IPV6
+
+    sock = TcpSocket.create(family)
+
+    await sock.connect(make_socket_address(address, port))
+
+    send_tx, send_rx = wit_world.byte_stream()
+    async def write() -> None:
+        with send_tx:
+            await send_tx.write_all(b"hello, world!")
+    await asyncio.gather(sock.send(send_rx), write())
+
+    recv_rx, recv_fut = sock.receive()
+    async def read() -> None:
+        with recv_rx:
+            data = await recv_rx.read(1024)
+            print(f"received: {str(data)}")
+    await asyncio.gather(recv_fut.read(), read())

tests/bindings.rs

@@ -171,6 +171,25 @@ fn lint_tcp_bindings() -> anyhow::Result<()> {
     Ok(())
 }
 
+#[test]
+fn lint_tcp_p3_bindings() -> anyhow::Result<()> {
+    let dir = tempfile::tempdir()?;
+    fs_extra::copy_items(
+        &["./examples/tcp-p3", "./wit"],
+        dir.path(),
+        &CopyOptions::new(),
+    )?;
+    let path = dir.path().join("tcp-p3");
+
+    generate_bindings(&path, "wasi:cli/command@0.3.0-rc-2026-01-06")?;
+
+    assert!(predicate::path::is_dir().eval(&path.join("wit_world")));
+
+    mypy_check(&path, ["--strict", "-m", "app"]);
+
+    Ok(())
+}
+
 fn generate_bindings(path: &Path, world: &str) -> Result<Assert, anyhow::Error> {
     Ok(cargo::cargo_bin_cmd!("componentize-py")
         .current_dir(path)

tests/componentize.rs

@@ -1,3 +1,4 @@
+use core::net::Ipv4Addr;
 use std::{
     io::Write,
     path::{Path, PathBuf},
@@ -241,21 +242,30 @@ fn sandbox_example() -> anyhow::Result<()> {
 
 #[test]
 fn tcp_example() -> anyhow::Result<()> {
+    test_tcp_example("tcp", "wasi:cli/command@0.2.0")
+}
+
+#[test]
+fn tcp_p3_example() -> anyhow::Result<()> {
+    test_tcp_example("tcp-p3", "wasi:cli/command@0.3.0-rc-2026-01-06")
+}
+
+fn test_tcp_example(name: &str, world: &str) -> anyhow::Result<()> {
     let dir = tempfile::tempdir()?;
     fs_extra::copy_items(
-        &["./examples/tcp", "./wit"],
+        &[format!("./examples/{name}").as_str(), "./wit"],
         dir.path(),
         &CopyOptions::new(),
     )?;
-    let path = dir.path().join("tcp");
+    let path = dir.path().join(name);
 
     cargo::cargo_bin_cmd!("componentize-py")
         .current_dir(&path)
         .args([
             "-d",
             "../wit",
             "-w",
-            "wasi:cli/command@0.2.0",
+            world,
             "componentize",
             "app",
             "-o",
@@ -265,16 +275,17 @@ fn tcp_example() -> anyhow::Result<()> {
         .success()
         .stdout("Component built successfully\n");
 
-    let listener = std::net::TcpListener::bind("127.0.0.1:3456")?;
+    let listener = std::net::TcpListener::bind((Ipv4Addr::LOCALHOST, 0))?;
+    let port = listener.local_addr()?.port();
 
     let tcp_handle = std::process::Command::new("wasmtime")
         .current_dir(&path)
         .args([
             "run",
-            "--wasi",
-            "inherit-network",
+            "-Sp3,inherit-network",
+            "-Wcomponent-model-async",
             "tcp.wasm",
-            "127.0.0.1:3456",
+            &format!("127.0.0.1:{port}"),
         ])
         .stdout(Stdio::piped())
         .spawn()?;