[Router] Add WASM pluggable OnRequest middleware

.buildkite/pipeline.yml

@@ -145,6 +145,8 @@ steps:
                 - -c
                 - |
                   apt-get update && apt-get install -y pkg-config libssl-dev protobuf-compiler
+                  # wasm_middleware unit tests load the example component artifact
+                  bash examples/wasm_middleware/build.sh
                   cargo test --lib --bins
         agents:
           queue: "cpu_queue_premerge"
@@ -183,6 +185,9 @@ steps:
                 - -c
                 - |
                   apt-get update && apt-get install -y pkg-config libssl-dev protobuf-compiler python3 python3-pip python3-dev python3-venv
+                  # WASM middleware pytest needs the example component + router binary
+                  bash examples/wasm_middleware/build.sh
+                  cargo build --release --bin vllm-router
                   python3 -m venv /tmp/venv
                   source /tmp/venv/bin/activate
                   pip install -U pip setuptools wheel setuptools-rust

.github/workflows/codespell.yml

@@ -13,4 +13,4 @@ jobs:
         with:
           check_filenames: true
           skip: ./.git,./.github/workflows/codespell.yml,.git,*.png,*.jpg,*.svg,*.sum
-          ignore_words_list: "aks,te,hel"
+          ignore_words_list: "aks,te,hel,wit,wast"

.github/workflows/wasm-middleware.yml

@@ -0,0 +1,61 @@
+name: WASM Middleware
+
+on:
+  pull_request:
+    paths:
+      - "src/wasm_middleware.rs"
+      - "src/server.rs"
+      - "src/main.rs"
+      - "src/lib.rs"
+      - "wit/**"
+      - "examples/wasm_middleware/**"
+      - "py_test/integration/test_wasm_middleware.py"
+      - "py_test/fixtures/router_manager.py"
+      - "py_test/fixtures/mock_worker.py"
+      - "tests/test_wasm_middleware.rs"
+      - "tests/common/**"
+      - "Cargo.toml"
+      - "Cargo.lock"
+      - ".github/workflows/wasm-middleware.yml"
+  push:
+    branches: [main]
+    paths:
+      - "src/wasm_middleware.rs"
+      - "wit/**"
+      - "examples/wasm_middleware/**"
+      - ".github/workflows/wasm-middleware.yml"
+
+jobs:
+  wasm-middleware:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32-wasip2
+
+      - name: Cache cargo
+        uses: Swatinem/rust-cache@v2
+
+      - name: Build example WASM plugin
+        working-directory: examples/wasm_middleware
+        run: ./build.sh
+
+      - name: Run WASM middleware unit tests
+        run: "cargo test --lib wasm_middleware:: -- --nocapture"
+
+      - name: Run WASM middleware Rust integration tests
+        run: "cargo test --test test_wasm_middleware -- --nocapture"
+
+      - name: Build router binary for integration tests
+        run: cargo build --release --bin vllm-router
+
+      - name: Install Python test deps
+        run: |
+          python3 -m pip install --upgrade pip
+          python3 -m pip install pytest requests fastapi uvicorn
+
+      - name: Run WASM middleware Python integration test
+        run: python3 -m pytest py_test/integration/test_wasm_middleware.py -q