[release-13.0] Backport stream backpressure and associated fixups to 13.0

.gitmodules

@@ -1,10 +1,10 @@
-[submodule "spec_testsuite"]
+[submodule "tests/spec_testsuite"]
 	path = tests/spec_testsuite
 	url = https://github.com/WebAssembly/testsuite
-[submodule "crates/c-api/examples/wasm-c-api"]
+[submodule "crates/c-api/wasm-c-api"]
 	path = crates/c-api/wasm-c-api
 	url = https://github.com/WebAssembly/wasm-c-api
-[submodule "WASI"]
+[submodule "crates/wasi-common/WASI"]
 	path = crates/wasi-common/WASI
 	url = https://github.com/WebAssembly/WASI
 [submodule "crates/wasi-nn/spec"]
@@ -13,10 +13,7 @@
 [submodule "tests/wasi_testsuite/wasi-threads"]
 	path = tests/wasi_testsuite/wasi-threads
 	url = https://github.com/WebAssembly/wasi-threads
-[submodule "crates/wasi-http/wasi-http"]
-	path = crates/wasi-http/wasi-http
-	url = https://github.com/WebAssembly/wasi-http
-[submodule "tests/wasi_testsuite/wasi"]
+[submodule "tests/wasi_testsuite/wasi-common"]
 	path = tests/wasi_testsuite/wasi-common
 	url = https://github.com/WebAssembly/wasi-testsuite.git
 	branch = prod/testsuite-base

Cargo.toml

@@ -258,6 +258,8 @@ futures = { version = "0.3.27", default-features = false }
 indexmap = "2.0.0"
 pretty_env_logger = "0.5.0"
 syn = "2.0.25"
+test-log = { version = "0.2", default-features = false, features = ["trace"] }
+tracing-subscriber = { version = "0.3.1", default-features = false, features = ['fmt', 'env-filter'] }
 
 [features]
 default = [

RELEASES.md

@@ -87,6 +87,11 @@ Unreleased.
   be turned off.
   [#6547](https://github.com/bytecodealliance/wasmtime/pull/6547)
 
+* WASI Preview 2 output-stream has been redesigned with changes to
+  backpressure and flushing. The `HostOutputStream` trait has changed
+  substantially.
+  [#6877](https://github.com/bytecodealliance/wasmtime/pull/6877)
+
 ### Removed
 
 * Wasmtime's experimental implementation of wasi-crypto has been removed. More

ci/build-test-matrix.js

@@ -95,7 +95,13 @@ const array = [
     "qemu_target": "riscv64-linux-user",
     "name": "Test Linux riscv64",
     "filter": "linux-riscv64",
-    "isa": "riscv64"
+    "isa": "riscv64",
+    // There appears to be a miscompile in Rust 1.72 for riscv64 where
+    // wasmtime-wasi tests are segfaulting in CI with the stack pointing in
+    // Tokio. Updating rustc seems to do the trick, so without doing a full
+    // rigorous investigation this uses beta for now but Rust 1.73 should be
+    // good to go for this.
+    "rust": "beta-2023-09-10",
   }
 ];
 

crates/test-programs/Cargo.toml

@@ -26,12 +26,9 @@ tracing = { workspace = true }
 [dev-dependencies]
 anyhow = { workspace = true }
 tempfile = { workspace = true }
-test-log = { version = "0.2", default-features = false, features = ["trace"] }
+test-log = { workspace = true }
 tracing = { workspace = true }
-tracing-subscriber = { version = "0.3.1", default-features = false, features = [
-    'fmt',
-    'env-filter',
-] }
+tracing-subscriber = { workspace = true }
 lazy_static = "1"
 wasmtime = { workspace = true, features = ['cranelift', 'component-model'] }
 

crates/test-programs/reactor-tests/src/lib.rs

@@ -3,9 +3,21 @@ wit_bindgen::generate!("test-reactor" in "../../wasi/wit");
 export_test_reactor!(T);
 
 struct T;
+use wasi::io::streams;
+use wasi::poll::poll;
 
 static mut STATE: Vec<String> = Vec::new();
 
+struct DropPollable {
+    pollable: poll::Pollable,
+}
+
+impl Drop for DropPollable {
+    fn drop(&mut self) {
+        poll::drop_pollable(self.pollable);
+    }
+}
+
 impl TestReactor for T {
     fn add_strings(ss: Vec<String>) -> u32 {
         for s in ss {
@@ -24,10 +36,38 @@ impl TestReactor for T {
     }
 
     fn write_strings_to(o: OutputStream) -> Result<(), ()> {
+        let sub = DropPollable {
+            pollable: streams::subscribe_to_output_stream(o),
+        };
         unsafe {
             for s in STATE.iter() {
-                wasi::io::streams::write(o, s.as_bytes()).map_err(|_| ())?;
+                let mut out = s.as_bytes();
+                while !out.is_empty() {
+                    poll::poll_oneoff(&[sub.pollable]);
+                    let n = match streams::check_write(o) {
+                        Ok(n) => n,
+                        Err(_) => return Err(()),
+                    };
+
+                    let len = (n as usize).min(out.len());
+                    match streams::write(o, &out[..len]) {
+                        Ok(_) => out = &out[len..],
+                        Err(_) => return Err(()),
+                    }
+                }
             }
+
+            match streams::flush(o) {
+                Ok(_) => {}
+                Err(_) => return Err(()),
+            }
+
+            poll::poll_oneoff(&[sub.pollable]);
+            match streams::check_write(o) {
+                Ok(_) => {}
+                Err(_) => return Err(()),
+            }
+
             Ok(())
         }
     }

crates/test-programs/tests/reactor.rs

@@ -103,7 +103,7 @@ async fn reactor_tests() -> Result<()> {
     // `host` and `wasi-common` crate.
     // Note, this works because of the add_to_linker invocations using the
     // `host` crate for `streams`, not because of `with` in the bindgen macro.
-    let writepipe = preview2::pipe::MemoryOutputPipe::new();
+    let writepipe = preview2::pipe::MemoryOutputPipe::new(4096);
     let table_ix = preview2::TableStreamExt::push_output_stream(
         store.data_mut().table_mut(),
         Box::new(writepipe.clone()),

crates/test-programs/tests/wasi-http-components-sync.rs

@@ -69,8 +69,8 @@ fn instantiate_component(
 }
 
 fn run(name: &str) -> anyhow::Result<()> {
-    let stdout = MemoryOutputPipe::new();
-    let stderr = MemoryOutputPipe::new();
+    let stdout = MemoryOutputPipe::new(4096);
+    let stderr = MemoryOutputPipe::new(4096);
     let r = {
         let mut table = Table::new();
         let component = get_component(name);

crates/test-programs/tests/wasi-http-components.rs

@@ -70,8 +70,8 @@ async fn instantiate_component(
 }
 
 async fn run(name: &str) -> anyhow::Result<()> {
-    let stdout = MemoryOutputPipe::new();
-    let stderr = MemoryOutputPipe::new();
+    let stdout = MemoryOutputPipe::new(4096);
+    let stderr = MemoryOutputPipe::new(4096);
     let r = {
         let mut table = Table::new();
         let component = get_component(name);

crates/test-programs/tests/wasi-http-modules.rs

@@ -74,8 +74,8 @@ async fn instantiate_module(module: Module, ctx: Ctx) -> Result<(Store<Ctx>, Fun
 }
 
 async fn run(name: &str) -> anyhow::Result<()> {
-    let stdout = MemoryOutputPipe::new();
-    let stderr = MemoryOutputPipe::new();
+    let stdout = MemoryOutputPipe::new(4096);
+    let stderr = MemoryOutputPipe::new(4096);
     let r = {
         let mut table = Table::new();
         let module = get_module(name);

crates/test-programs/tests/wasi-preview1-host-in-preview2.rs

@@ -30,8 +30,8 @@ pub fn prepare_workspace(exe_name: &str) -> Result<TempDir> {
 
 async fn run(name: &str, inherit_stdio: bool) -> Result<()> {
     let workspace = prepare_workspace(name)?;
-    let stdout = MemoryOutputPipe::new();
-    let stderr = MemoryOutputPipe::new();
+    let stdout = MemoryOutputPipe::new(4096);
+    let stderr = MemoryOutputPipe::new(4096);
     let r = {
         let mut linker = Linker::new(&ENGINE);
         add_to_linker_async(&mut linker)?;

crates/test-programs/tests/wasi-preview2-components-sync.rs

@@ -30,8 +30,8 @@ pub fn prepare_workspace(exe_name: &str) -> Result<TempDir> {
 
 fn run(name: &str, inherit_stdio: bool) -> Result<()> {
     let workspace = prepare_workspace(name)?;
-    let stdout = MemoryOutputPipe::new();
-    let stderr = MemoryOutputPipe::new();
+    let stdout = MemoryOutputPipe::new(4096);
+    let stderr = MemoryOutputPipe::new(4096);
     let r = {
         let mut linker = Linker::new(&ENGINE);
         add_to_linker(&mut linker)?;

crates/test-programs/tests/wasi-preview2-components.rs

@@ -30,8 +30,8 @@ pub fn prepare_workspace(exe_name: &str) -> Result<TempDir> {
 
 async fn run(name: &str, inherit_stdio: bool) -> Result<()> {
     let workspace = prepare_workspace(name)?;
-    let stdout = MemoryOutputPipe::new();
-    let stderr = MemoryOutputPipe::new();
+    let stdout = MemoryOutputPipe::new(4096);
+    let stderr = MemoryOutputPipe::new(4096);
     let r = {
         let mut linker = Linker::new(&ENGINE);
         add_to_linker(&mut linker)?;

crates/test-programs/wasi-http-tests/src/lib.rs

@@ -7,7 +7,7 @@ pub mod bindings {
     });
 }
 
-use anyhow::{anyhow, Context, Result};
+use anyhow::{anyhow, Result};
 use std::fmt;
 use std::sync::OnceLock;
 
@@ -42,6 +42,16 @@ impl Response {
     }
 }
 
+struct DropPollable {
+    pollable: poll::Pollable,
+}
+
+impl Drop for DropPollable {
+    fn drop(&mut self) {
+        poll::drop_pollable(self.pollable);
+    }
+}
+
 pub async fn request(
     method: http_types::Method,
     scheme: http_types::Scheme,
@@ -72,27 +82,39 @@ pub async fn request(
     let request_body = http_types::outgoing_request_write(request)
         .map_err(|_| anyhow!("outgoing request write failed"))?;
 
-    if let Some(body) = body {
-        let output_stream_pollable = streams::subscribe_to_output_stream(request_body);
-        let len = body.len();
-        if len == 0 {
-            let (_written, _status) = streams::write(request_body, &[])
-                .map_err(|_| anyhow!("request_body stream write failed"))
-                .context("writing empty request body")?;
-        } else {
-            let mut body_cursor = 0;
-            while body_cursor < body.len() {
-                let (written, _status) = streams::write(request_body, &body[body_cursor..])
-                    .map_err(|_| anyhow!("request_body stream write failed"))
-                    .context("writing request body")?;
-                body_cursor += written as usize;
+    if let Some(mut buf) = body {
+        let sub = DropPollable {
+            pollable: streams::subscribe_to_output_stream(request_body),
+        };
+        while !buf.is_empty() {
+            poll::poll_oneoff(&[sub.pollable]);
+
+            let permit = match streams::check_write(request_body) {
+                Ok(n) => usize::try_from(n)?,
+                Err(_) => anyhow::bail!("output stream error"),
+            };
+
+            let len = buf.len().min(permit);
+            let (chunk, rest) = buf.split_at(len);
+            buf = rest;
+
+            match streams::write(request_body, chunk) {
+                Err(_) => anyhow::bail!("output stream error"),
+                _ => {}
             }
         }
 
-        // TODO: enable when working as expected
-        // let _ = poll::poll_oneoff(&[output_stream_pollable]);
+        match streams::flush(request_body) {
+            Err(_) => anyhow::bail!("output stream error"),
+            _ => {}
+        }
+
+        poll::poll_oneoff(&[sub.pollable]);
 
-        poll::drop_pollable(output_stream_pollable);
+        match streams::check_write(request_body) {
+            Ok(_) => {}
+            Err(_) => anyhow::bail!("output stream error"),
+        };
     }
 
     let future_response = outgoing_handler::handle(request, None);