[Proposal] Use native stdio streams in the Node SDK by bbonaby · Pull Request #1220 · microsoft/mxc

Branden Bonaby (bbonaby) · 2026-09-19T00:39:51Z

📖 Description

Replace callback-driven byte coordination with direct native stdio ownership in the Node SDK. Rust retains process lifecycle control, while Node adopts Windows HANDLEs through windowsHandle and Unix file descriptors through net.Socket.

Streaming remains limited to process-backed backends that expose transferable native endpoints. The Node SDK now requires Node.js 24.21.0 or later.

🔗 References

🔍 Validation

cargo fmt --all -- --check
Windows cargo check -p mxc_engine -p mxc_ffi
Linux cross-check for x86_64-unknown-linux-gnu
Focused mxc_engine and mxc_ffi lifecycle tests
Node SDK build and unit-test compilation
Native streaming unit tests on Node.js 24.21.0
Integration TypeScript type-check

The native streaming integration workload was not run on this development machine.

✅ Checklist

Signed the Contributor License Agreement
Linked to an issue
Updated documentation (if applicable)
Updated Copilot instructions (if build, architecture, or conventions changed)
If this PR changes Cargo.lock, the dependency-feed-check check passes (see docs/pull-requests.md)

📋 Issue Type

Bug fix
Feature
Task

Microsoft Reviewers: Open in CodeFlow

Move blocking stream, process-control, timeout, and state-aware execution work onto native threads and expose callback-driven completion through mxc_ffi. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bbe1ffbf-7cf8-48a0-8e3b-956f1d634e6c

Transfer caller-owned native pipe endpoints for the four pipe-backed streaming backends and expose them through the SDK and C ABI. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bbe1ffbf-7cf8-48a0-8e3b-956f1d634e6c

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bbe1ffbf-7cf8-48a0-8e3b-956f1d634e6c

azure-pipelines · 2026-09-19T00:40:01Z

Azure Pipelines: There may be pipelines that require an authorized user to comment /azp run to run.

Branden Bonaby (bbonaby) · 2026-09-19T00:43:42Z

Closing because this PR was opened prematurely without the user's authorization. The branch remains available for continued work.

Copilot

Copilot review overview

🟡 Changes recommended

Wrapper omissions break native streaming, stdin errors can incorrectly fail waits, and both npm lockfiles violate CI integrity rules.

Get a fresh assessment by requesting another Copilot review.

Review effort: Balanced
Findings: 2 · 5

Open (7)

Regenerate package lockfile with public npm registry · New
Regenerate integration lockfile with public npm registry · New
Ignore normal stdin EPIPE during waitAsync · New
Delegate take_native_stdio in OneShotSandboxProcess · New
Delegate take_native_stdio in DaclGuardedProcess · New
Delegate take_native_stdio in TelemetryProcess · New
Delegate take_native_stdio in ProcessWithWarnings · New

What changed in this PR

Reworks Node SDK streaming to transfer native stdio handles while Rust retains process lifecycle control.

Changes:

Adds native stdio ownership and lifecycle coordination across Rust, FFI, and Node.
Adds streaming tests and raises the minimum Node.js version to 24.21.0.
Updates documentation, dependencies, and CI environments.

File	Description
`src/ffi/mxc_ffi/src/lib.rs`	Exposes event-loop streaming FFI.
`src/ffi/mxc_ffi/src/io_coordinator.rs`	Implements native lifecycle C APIs.
`src/ffi/mxc_ffi/Cargo.toml`	Adds engine dependency.
`src/ffi/mxc_ffi/build.rs`	Tracks the new FFI source.
`src/core/wxc_common/src/sandbox_process.rs`	Adds native stdio abstractions.
`src/core/wxc_common/src/process_util.rs`	Adds Windows handle duplication.
`src/core/wxc_common/src/interruptible_reader.rs`	Adds Unix descriptor duplication.
`src/core/wxc_common/src/exec_stream.rs`	Exposes exec native endpoints.
`src/core/mxc-sdk/src/sandbox.rs`	Forwards native stdio access.
`src/core/mxc_engine/src/lib.rs`	Exports and integrates coordination.
`src/core/mxc_engine/src/io_coordinator.rs`	Implements lifecycle coordination.
`src/core/mxc_engine/Cargo.toml`	Adds channel dependency.
`src/Cargo.toml`	Registers workspace dependency.
`src/Cargo.lock`	Updates Rust dependency resolution.
`src/backends/seatbelt/common/src/seatbelt_runner.rs`	Transfers Seatbelt endpoints.
`src/backends/process_container/common/src/dispatcher.rs`	Updates process wrapper delegation.
`src/backends/process_container/common/src/base_container_runner.rs`	Adds native handles and timeout state.
`src/backends/process_container/common/src/appcontainer_runner.rs`	Adds native handles and timeout state.
`src/backends/isolation_session/common/src/sandbox.rs`	Updates one-shot wrapper delegation.
`src/backends/bubblewrap/common/src/bwrap_runner.rs`	Transfers Bubblewrap endpoints.
`sdk/node/tests/unit/streaming-binding.test.ts`	Tests native binding ownership.
`sdk/node/tests/unit/sandbox-process.test.ts`	Tests lifecycle behavior.
`sdk/node/tests/integration/package.json`	Updates integration dependencies.
`sdk/node/tests/integration/package-lock.json`	Refreshes integration lock data.
`sdk/node/tests/integration/native-streaming.test.ts`	Adds native streaming integration coverage.
`sdk/node/src/sandbox-process.ts`	Implements Node process lifecycle API.
`sdk/node/src/bindings/streaming.ts`	Adopts native handles as streams.
`sdk/node/README.md`	Documents the Node requirement.
`sdk/node/package.json`	Raises the Node engine version.
`sdk/node/package-lock.json`	Refreshes SDK lock data.
`docs/isolation-session/state-aware-rust.md`	Documents state-aware streaming.
`docs/architecture.md`	Updates SDK and FFI architecture.
`.github/workflows/Versioning.Checks.Job.yml`	Updates versioning CI Node runtime.
`.github/workflows/SDK.Unit.Test.Job.yml`	Updates unit-test Node runtime.
`.github/workflows/SDK.Integration.Test.Job.yml`	Updates integration-test Node runtime.
`.github/workflows/Package.NpmSdk.Job.yml`	Updates packaging Node runtime.
`.github/workflows/Package.Lock.Check.Job.yml`	Updates lock-check Node runtime.
`.azure-pipelines/templates/SDK.Unit.Test.Job.yml`	Updates Azure unit-test runtime.
`.azure-pipelines/templates/SDK.Integration.Test.Job.yml`	Updates Azure integration runtime.
`.azure-pipelines/templates/Package.NpmSdk.Job.yml`	Updates Azure packaging runtime.
`.azure-pipelines/templates/Package.Lock.Check.Job.yml`	Updates Azure lock-check runtime.
`.azure-pipelines/templates/IsolationSession.TestBundle.Build.Job.yml`	Updates test-bundle Node runtime.

Files not reviewed (2)

sdk/node/package-lock.json: Generated file
sdk/node/tests/integration/package-lock.json: Generated file

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+      "resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@types/node/-/node-24.13.4.tgz",
+      "integrity": "sha1-5U90zq5oOL/1eoFLfTH1BCoPkHQ=",


+      "resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@koromix/koffi-android-arm64/-/koffi-android-arm64-3.2.1.tgz",
+      "integrity": "sha1-Lc55jTZp0re1bpwCqKaidKvWx8Y=",


+      this.rejectWait = reject;
+    });
+    void this.waitPromise.catch(() => {});
+    this.input?.on('error', (error) => void this.finish(undefined, asError(error)));


+    fn stdin_closer(&self) -> Option<Box<dyn StreamCloser>> {
+        self.inner.stdin_closer()
+    }


+    fn stdin_closer(&self) -> Option<Box<dyn wxc_common::sandbox_process::StreamCloser>> {
+        self.inner.stdin_closer()
+    }


+    fn stdin_closer(&self) -> Option<Box<dyn wxc_common::sandbox_process::StreamCloser>> {
+        self.inner.stdin_closer()
+    }


+    fn stdin_closer(&self) -> Option<Box<dyn wxc_common::sandbox_process::StreamCloser>> {
+        self.inner.stdin_closer()
+    }


Branden Bonaby (bbonaby) added 4 commits September 18, 2026 12:19

Replace byte coordination with lifecycle control

e4b2fbd

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bbe1ffbf-7cf8-48a0-8e3b-956f1d634e6c

Adopt native stdio streams in Node

beb27f2

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bbe1ffbf-7cf8-48a0-8e3b-956f1d634e6c

Branden Bonaby (bbonaby) requested a review from a team as a code owner September 19, 2026 00:39

Copilot AI balanced review requested due to automatic review settings September 19, 2026 00:39

Copilot started reviewing on behalf of Branden Bonaby (bbonaby) September 19, 2026 00:40 View session

Branden Bonaby (bbonaby) closed this Sep 19, 2026

Copilot AI reviewed Sep 19, 2026

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[Proposal] Use native stdio streams in the Node SDK - #1220

[Proposal] Use native stdio streams in the Node SDK#1220
Branden Bonaby (bbonaby) wants to merge 4 commits into
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Branden Bonaby (bbonaby) commented Sep 19, 2026 •

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		"resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@types/node/-/node-24.13.4.tgz",
		"integrity": "sha1-5U90zq5oOL/1eoFLfTH1BCoPkHQ=",

		"resolved": "https://ms-feed-25.pkgs.visualstudio.com/1es-public/_packaging/npm-public/npm/registry/@koromix/koffi-android-arm64/-/koffi-android-arm64-3.2.1.tgz",
		"integrity": "sha1-Lc55jTZp0re1bpwCqKaidKvWx8Y=",

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📖 Description

🔗 References

🔍 Validation

✅ Checklist

📋 Issue Type

Microsoft Reviewers: Open in CodeFlow

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Branden Bonaby (bbonaby) commented Sep 19, 2026 •

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