Hacked up tracy capture during client tests

.github/workflows/build.yml

@@ -43,6 +43,7 @@ jobs:
         with:
           distribution: 'microsoft'
           java-version: '21'
+      - run: brew install tracy
       - run: mkdir run && echo "eula=true" >> run/eula.txt
       - name: Run Client Gametests
         uses: modmuss50/xvfb-action@v1
@@ -53,6 +54,10 @@ jobs:
         with:
           name: Test Screenshots
           path: run/screenshots
+      - uses: actions/upload-artifact@v4
+        with:
+          name: Test Trace
+          path: run/profile.tracy
 
   server_test:
     runs-on: ubuntu-22.04

build.gradle

@@ -515,7 +515,8 @@ tasks.register('runProductionClientGametest', JavaExec) {
 		args(
 				"--assetIndex", loom.minecraftProvider.versionInfo.assetIndex().fabricId(loom.minecraftProvider.minecraftVersion()),
 				"--assetsDir", new File(loom.files.userCache, "assets").absolutePath,
-				"--gameDir", workingDir.absolutePath
+				"--gameDir", workingDir.absolutePath,
+				"--tracy"
 				)
 
 		if (Platform.CURRENT.operatingSystem.isMacOS()) {

fabric-client-gametest-api-v1/src/client/java/net/fabricmc/fabric/impl/client/gametest/tracy/TracyCapture.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.impl.client.gametest.tracy;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class TracyCapture {
+	private static final Logger LOGGER = LoggerFactory.getLogger(TracyCapture.class);
+	private final Path output;
+
+	@Nullable
+	private Process process = null;
+
+	public TracyCapture(Path output) {
+		this.output = output;
+	}
+
+	public void startCapture() {
+		try {
+			Files.createDirectories(output.getParent());
+			LOGGER.info("Starting tracy-capture");
+			process = createProcess().start();
+		} catch (IOException e) {
+			throw new UncheckedIOException("Failed to start tracy-capture", e);
+		}
+
+		// Send ctrl+c on shutdown
+		Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+			if (process != null) {
+				LOGGER.info("Stopping tracy-capture");
+
+				try {
+					// Send ctrl+c
+					long pid = process.pid(); // Requires Java 9+
+					ProcessBuilder killProcess = new ProcessBuilder("kill", "-SIGINT", String.valueOf(pid));
+					killProcess.inheritIO().start();
+
+					process.waitFor();
+					LOGGER.info("tracy-capture finished with exit code {}", process.exitValue());
+					LOGGER.info(new String(process.getInputStream().readAllBytes()));
+				} catch (InterruptedException e) {
+					LOGGER.error("tracy-capture was interrupted", e);
+				} catch (IOException e) {
+					throw new RuntimeException(e);
+				}
+			}
+		}));
+	}
+
+	private ProcessBuilder createProcess() {
+		return new ProcessBuilder()
+		.command(
+			"tracy-capture",
+			"-o", output.toAbsolutePath().toString(),
+			"-a", "127.0.0.1",
+			"-f"
+		);
+	}
+}

fabric-client-gametest-api-v1/src/client/java/net/fabricmc/fabric/impl/client/gametest/tracy/TracyEntrypoint.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.impl.client.gametest.tracy;
+
+import java.nio.file.Path;
+import java.util.Arrays;
+
+import net.fabricmc.loader.api.FabricLoader;
+import net.fabricmc.loader.api.entrypoint.PreLaunchEntrypoint;
+
+public class TracyEntrypoint implements PreLaunchEntrypoint {
+	private static final boolean ENABLED = System.getProperty("fabric.client.gametest") != null;
+
+	private static TracyCapture tracyCapture;
+
+	@Override
+	public void onPreLaunch() {
+		if (!ENABLED) {
+			return;
+		}
+
+		if (!Arrays.asList(FabricLoader.getInstance().getLaunchArguments(true)).contains("--tracy")) {
+			return;
+		}
+
+		Path output = FabricLoader.getInstance().getGameDir().resolve("profile.tracy");
+		tracyCapture = new TracyCapture(output);
+		tracyCapture.startCapture();
+	}
+}

fabric-client-gametest-api-v1/src/client/resources/fabric.mod.json

@@ -26,5 +26,10 @@
   "accessWidener": "fabric-client-gametest-api-v1.accesswidener",
   "custom": {
     "fabric-api:module-lifecycle": "experimental"
+  },
+  "entrypoints": {
+    "preLaunch": [
+      "net.fabricmc.fabric.impl.client.gametest.tracy.TracyEntrypoint"
+    ]
   }
 }