Reduce idle work and improve resource diagnostics with native telemetry

.github/workflows/ci.yml

@@ -22,6 +22,9 @@ jobs:
           cache: true
           run-install: true
 
+      - name: Setup Rust
+        uses: dtolnay/rust-toolchain@stable
+
       - name: Ensure Electron runtime is installed
         run: vp run --filter @t3tools/desktop ensure:electron
 
@@ -31,6 +34,9 @@ jobs:
       - name: Typecheck
         run: vpr typecheck
 
+      - name: Check resource monitor formatting
+        run: cargo fmt --manifest-path native/resource-monitor/Cargo.toml -- --check
+
       - name: Build desktop pipeline
         run: vp run build:desktop
 
@@ -54,12 +60,18 @@ jobs:
           cache: true
           run-install: true
 
+      - name: Setup Rust
+        uses: dtolnay/rust-toolchain@stable
+
       - name: Ensure Electron runtime is installed
         run: vp run --filter @t3tools/desktop ensure:electron
 
       - name: Test
         run: vp run test
 
+      - name: Test resource monitor
+        run: cargo test --locked --manifest-path native/resource-monitor/Cargo.toml
+
   test_browser:
     name: Test Browser
     runs-on: blacksmith-8vcpu-ubuntu-2404

.github/workflows/release.yml

@@ -272,21 +272,29 @@ jobs:
             platform: mac
             target: dmg
             arch: arm64
+            rust_target: aarch64-apple-darwin
+            resource_key: darwin-arm64
           - label: macOS x64
             runner: blacksmith-12vcpu-macos-26
             platform: mac
             target: dmg
             arch: x64
+            rust_target: x86_64-apple-darwin
+            resource_key: darwin-x64
           - label: Linux x64
             runner: blacksmith-32vcpu-ubuntu-2404
             platform: linux
             target: AppImage
             arch: x64
+            rust_target: x86_64-unknown-linux-gnu
+            resource_key: linux-x64
           - label: Windows x64
             runner: blacksmith-32vcpu-windows-2025
             platform: win
             target: nsis
             arch: x64
+            rust_target: x86_64-pc-windows-msvc
+            resource_key: win32-x64
           # - label: Windows arm64
           #   runner: windows-11-arm
           #   platform: win
@@ -306,6 +314,11 @@ jobs:
           cache: true
           run-install: true
 
+      - name: Setup Rust
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.rust_target }}
+
       - name: Download relay client tracing config
         uses: actions/download-artifact@v8
         with:
@@ -518,13 +531,33 @@ jobs:
           #   done
           # fi
 
+      - name: Collect resource monitor
+        shell: bash
+        run: |
+          set -euo pipefail
+          binary_name="t3-resource-monitor"
+          if [[ "${{ matrix.platform }}" == "win" ]]; then
+            binary_name="${binary_name}.exe"
+          fi
+          source_path="native/resource-monitor/target/${{ matrix.rust_target }}/release/${binary_name}"
+          target_dir="resource-monitor-publish/${{ matrix.resource_key }}"
+          mkdir -p "$target_dir"
+          cp "$source_path" "$target_dir/$binary_name"
+
       - name: Upload build artifacts
         uses: actions/upload-artifact@v7
         with:
           name: desktop-${{ matrix.platform }}-${{ matrix.arch }}
           path: release-publish/*
           if-no-files-found: error
 
+      - name: Upload resource monitor
+        uses: actions/upload-artifact@v7
+        with:
+          name: resource-monitor-${{ matrix.resource_key }}
+          path: resource-monitor-publish/${{ matrix.resource_key }}/*
+          if-no-files-found: error
+
   publish_cli:
     name: Publish CLI to npm
     needs: [preflight, relay_public_config, build]
@@ -579,6 +612,24 @@ jobs:
       - name: Build CLI package
         run: vp run --filter t3 build
 
+      - name: Download resource monitors
+        uses: actions/download-artifact@v8
+        with:
+          pattern: resource-monitor-*
+          path: ${{ runner.temp }}/resource-monitors
+
+      - name: Bundle resource monitors into CLI package
+        shell: bash
+        run: |
+          set -euo pipefail
+          for artifact_dir in "$RUNNER_TEMP"/resource-monitors/resource-monitor-*; do
+            resource_key="${artifact_dir##*/resource-monitor-}"
+            target_dir="apps/server/dist/resource-monitor/${resource_key}"
+            mkdir -p "$target_dir"
+            cp "$artifact_dir"/t3-resource-monitor* "$target_dir/"
+            chmod +x "$target_dir"/t3-resource-monitor 2>/dev/null || true
+          done
+
       - name: Publish CLI package
         run: node apps/server/scripts/cli.ts publish --tag "${{ needs.preflight.outputs.cli_dist_tag }}" --app-version "${{ needs.preflight.outputs.version }}" --verbose
 

.gitignore

@@ -27,6 +27,7 @@ squashfs-root/
 .gstack/
 dist-electron/
 .electron-runtime/
+native/**/target/
 node_modules/
 .alchemy/
 *.log

apps/desktop/src/app/DesktopAppIdentity.test.ts

@@ -54,6 +54,7 @@ const makeElectronAppLayer = (calls: ElectronAppCalls) =>
       }),
     setAppUserModelId: () => Effect.void,
     requestSingleInstanceLock: Effect.succeed(true),
+    getAppMetrics: Effect.succeed([]),
     isDefaultProtocolClient: () => Effect.succeed(false),
     setAsDefaultProtocolClient: () => Effect.succeed(true),
     setDesktopName: () => Effect.void,

apps/desktop/src/app/DesktopCloudAuth.test.ts

@@ -54,6 +54,7 @@ function makeHarness(input: { readonly isDevelopment: boolean }): CloudAuthHarne
     setAboutPanelOptions: () => Effect.void,
     setAppUserModelId: () => Effect.void,
     requestSingleInstanceLock: Effect.succeed(true),
+    getAppMetrics: Effect.succeed([]),
     isDefaultProtocolClient: () => Effect.succeed(false),
     setAsDefaultProtocolClient: (protocol, path, args) =>
       Effect.sync(() => {

apps/desktop/src/app/DesktopObservability.test.ts

@@ -49,14 +49,14 @@ const environmentInput = (baseDir: string) =>
     runningUnderArm64Translation: false,
   }) satisfies DesktopEnvironment.MakeDesktopEnvironmentInput;
 
-const makeEnvironmentLayer = (baseDir: string) =>
+const makeEnvironmentLayer = (baseDir: string, isDevelopment = true) =>
   DesktopEnvironment.layer(environmentInput(baseDir)).pipe(
     Layer.provide(
       Layer.mergeAll(
         NodeServices.layer,
         DesktopConfig.layerTest({
           T3CODE_HOME: baseDir,
-          VITE_DEV_SERVER_URL: "http://127.0.0.1:5733",
+          VITE_DEV_SERVER_URL: isDevelopment ? "http://127.0.0.1:5733" : undefined,
         }),
       ),
     ),
@@ -112,48 +112,155 @@ describe("DesktopObservability", () => {
     ),
   );
 
-  it.effect("persists backend child output as structured JSON records in development", () =>
+  it.effect("buffers backend child output and persists it only when a failure is reported", () =>
     Effect.gen(function* () {
       const fileSystem = yield* FileSystem.FileSystem;
       const baseDir = yield* fileSystem.makeTempDirectoryScoped({
         prefix: "t3-desktop-backend-output-log-test-",
       });
-      const environmentLayer = makeEnvironmentLayer(baseDir);
+      const environmentLayer = makeEnvironmentLayer(baseDir, false);
       const logPath = yield* Effect.gen(function* () {
         const environment = yield* DesktopEnvironment.DesktopEnvironment;
         return environment.path.join(environment.logDir, "server-child.log");
       }).pipe(Effect.provide(environmentLayer));
+      const tracePath = yield* Effect.gen(function* () {
+        const environment = yield* DesktopEnvironment.DesktopEnvironment;
+        return environment.path.join(environment.logDir, "desktop.trace.ndjson");
+      }).pipe(Effect.provide(environmentLayer));
 
-      yield* Effect.gen(function* () {
-        const outputLog = yield* DesktopObservability.DesktopBackendOutputLog;
-        yield* outputLog.writeSessionBoundary({
-          phase: "START",
-          details: "pid=123 port=3773 cwd=/repo",
-        });
-        yield* outputLog.writeOutputChunk("stdout", new TextEncoder().encode("hello server\n"));
-      }).pipe(
-        Effect.annotateLogs({ runId: "test-run" }),
-        Effect.provide(DesktopObservability.layer.pipe(Layer.provideMerge(environmentLayer))),
+      yield* Effect.scoped(
+        Effect.gen(function* () {
+          const outputLog = yield* DesktopObservability.DesktopBackendOutputLog;
+          yield* outputLog.beginSession({
+            details: "pid=123 port=3773 cwd=/repo",
+          });
+          yield* outputLog.writeOutputChunk("stdout", new TextEncoder().encode("hello server\n"));
+          assert.isFalse(yield* fileSystem.exists(logPath));
+          yield* outputLog.persistFailure({ details: "code=1" });
+          yield* outputLog.beginSession({ details: "pid=456" });
+          yield* outputLog.writeOutputChunk(
+            "stderr",
+            new TextEncoder().encode("normal shutdown\n"),
+          );
+          yield* outputLog.discardSession;
+        }).pipe(
+          Effect.annotateLogs({ runId: "test-run" }),
+          Effect.provide(DesktopObservability.layer.pipe(Layer.provideMerge(environmentLayer))),
+        ),
       );
 
       const log = yield* fileSystem.readFileString(logPath);
       const lines = log.trimEnd().split("\n");
-      const boundary = yield* decodeDesktopBackendChildLogRecord(lines[0] ?? "");
+      const start = yield* decodeDesktopBackendChildLogRecord(lines[0] ?? "");
       const output = yield* decodeDesktopBackendChildLogRecord(lines[1] ?? "");
+      const end = yield* decodeDesktopBackendChildLogRecord(lines[2] ?? "");
 
-      assert.equal(boundary.message, "backend child process session start");
-      assert.equal(boundary.level, "INFO");
-      assert.equal(boundary.annotations.component, "desktop-backend-child");
-      assert.equal(boundary.annotations.runId, "test-run");
-      assert.equal(boundary.annotations.phase, "START");
-      assert.equal(boundary.annotations.details, "pid=123 port=3773 cwd=/repo");
+      assert.equal(lines.length, 3);
+      assert.equal(start.message, "backend child process failure output start");
+      assert.equal(start.level, "ERROR");
+      assert.equal(start.annotations.component, "desktop-backend-child");
+      assert.equal(start.annotations.runId, "test-run");
+      assert.equal(start.annotations.phase, "START");
+      assert.equal(start.annotations.details, "pid=123 port=3773 cwd=/repo");
 
       assert.equal(output.message, "backend child process output");
       assert.equal(output.level, "INFO");
       assert.equal(output.annotations.component, "desktop-backend-child");
       assert.equal(output.annotations.runId, "test-run");
       assert.equal(output.annotations.stream, "stdout");
       assert.equal(output.annotations.text, "hello server\n");
+
+      assert.equal(end.message, "backend child process failure output end");
+      assert.equal(end.level, "ERROR");
+      assert.equal(end.annotations.phase, "END");
+      assert.equal(end.annotations.details, "code=1");
+
+      const traceRecords = (yield* fileSystem.readFileString(tracePath))
+        .trim()
+        .split("\n")
+        .filter((line) => line.length > 0)
+        .map((line) => decodeTraceRecordLine(line));
+      assert.isFalse(
+        traceRecords.some(
+          (record) => record.name === "desktop.observability.backendOutput.writeOutputChunk",
+        ),
+      );
+    }).pipe(
+      Effect.scoped,
+      Effect.provide(Layer.mergeAll(NodeServices.layer, NodeHttpClient.layerUndici)),
+    ),
+  );
+
+  it.effect("retains only the last mebibyte of backend child output", () =>
+    Effect.gen(function* () {
+      const fileSystem = yield* FileSystem.FileSystem;
+      const baseDir = yield* fileSystem.makeTempDirectoryScoped({
+        prefix: "t3-desktop-backend-output-bound-test-",
+      });
+      const environmentLayer = makeEnvironmentLayer(baseDir, false);
+      const logPath = yield* Effect.gen(function* () {
+        const environment = yield* DesktopEnvironment.DesktopEnvironment;
+        return environment.path.join(environment.logDir, "server-child.log");
+      }).pipe(Effect.provide(environmentLayer));
+      const maxBufferedBytes = 1024 * 1024;
+      const discardedPrefixBytes = 128;
+      const output = new Uint8Array(maxBufferedBytes + discardedPrefixBytes);
+      output.fill("x".charCodeAt(0));
+      output.fill("y".charCodeAt(0), 0, discardedPrefixBytes);
+
+      yield* Effect.scoped(
+        Effect.gen(function* () {
+          const outputLog = yield* DesktopObservability.DesktopBackendOutputLog;
+          yield* outputLog.beginSession({ details: "pid=123" });
+          yield* outputLog.writeOutputChunk("stderr", output);
+          yield* outputLog.persistFailure({ details: "code=1" });
+        }).pipe(
+          Effect.provide(DesktopObservability.layer.pipe(Layer.provideMerge(environmentLayer))),
+        ),
+      );
+
+      const lines = (yield* fileSystem.readFileString(logPath)).trimEnd().split("\n");
+      const record = yield* decodeDesktopBackendChildLogRecord(lines[1] ?? "");
+      const text = record.annotations.text;
+      assert.equal(typeof text, "string");
+      if (typeof text !== "string") {
+        return;
+      }
+      assert.equal(new TextEncoder().encode(text).byteLength, maxBufferedBytes);
+      assert.isFalse(text.includes("y"));
+    }).pipe(
+      Effect.scoped,
+      Effect.provide(Layer.mergeAll(NodeServices.layer, NodeHttpClient.layerUndici)),
+    ),
+  );
+
+  it.effect("bounds the number of retained backend child output chunks", () =>
+    Effect.gen(function* () {
+      const fileSystem = yield* FileSystem.FileSystem;
+      const baseDir = yield* fileSystem.makeTempDirectoryScoped({
+        prefix: "t3-desktop-backend-output-chunks-test-",
+      });
+      const environmentLayer = makeEnvironmentLayer(baseDir, false);
+      const logPath = yield* Effect.gen(function* () {
+        const environment = yield* DesktopEnvironment.DesktopEnvironment;
+        return environment.path.join(environment.logDir, "server-child.log");
+      }).pipe(Effect.provide(environmentLayer));
+
+      yield* Effect.scoped(
+        Effect.gen(function* () {
+          const outputLog = yield* DesktopObservability.DesktopBackendOutputLog;
+          yield* outputLog.beginSession({ details: "pid=123" });
+          for (let index = 0; index < 300; index += 1) {
+            yield* outputLog.writeOutputChunk("stderr", Uint8Array.of(index % 128));
+          }
+          yield* outputLog.persistFailure({ details: "code=1" });
+        }).pipe(
+          Effect.provide(DesktopObservability.layer.pipe(Layer.provideMerge(environmentLayer))),
+        ),
+      );
+
+      const lines = (yield* fileSystem.readFileString(logPath)).trimEnd().split("\n");
+      assert.equal(lines.length, 258);
     }).pipe(
       Effect.scoped,
       Effect.provide(Layer.mergeAll(NodeServices.layer, NodeHttpClient.layerUndici)),