trace_events: add process_name metadata

PR-URL: #21477
Reviewed-By: Bradley Farias <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>

Author: jasnell

src/node.cc

@@ -2178,6 +2178,8 @@ static void ProcessTitleSetter(Local<Name> property,
                                Local<Value> value,
                                const PropertyCallbackInfo<void>& info) {
   node::Utf8Value title(info.GetIsolate(), value);
+  TRACE_EVENT_METADATA1("__metadata", "process_name", "name",
+                        TRACE_STR_COPY(*title));
   uv_set_process_title(*title);
 }
 
@@ -4074,6 +4076,13 @@ inline int Start(Isolate* isolate, IsolateData* isolate_data,
   Environment env(isolate_data, context, v8_platform.GetTracingAgent());
   env.Start(argc, argv, exec_argc, exec_argv, v8_is_profiling);
 
+  char name_buffer[512];
+  if (uv_get_process_title(name_buffer, sizeof(name_buffer)) == 0) {
+    // Only emit the metadata event if the title can be retrieved successfully.
+    // Ignore it otherwise.
+    TRACE_EVENT_METADATA1("__metadata", "process_name", "name",
+                          TRACE_STR_COPY(name_buffer));
+  }
   TRACE_EVENT_METADATA1("__metadata", "version", "node", NODE_VERSION_STRING);
   TRACE_EVENT_METADATA1("__metadata", "thread_name", "name",
                         "JavaScriptMainThread");

test/parallel/test-trace-events-metadata.js

@@ -8,7 +8,8 @@ if (!common.isMainThread)
   common.skip('process.chdir is not available in Workers');
 
 const CODE =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1)';
+  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1);' +
+  'process.title = "foo"';
 const FILE_NAME = 'node_trace.1.log';
 
 const tmpdir = require('../common/tmpdir');
@@ -17,6 +18,7 @@ process.chdir(tmpdir.path);
 
 const proc = cp.spawn(process.execPath,
                       [ '--trace-event-categories', 'node.perf.usertiming',
+                        '--title=bar',
                         '-e', CODE ]);
 proc.once('exit', common.mustCall(() => {
   assert(common.fileExists(FILE_NAME));
@@ -32,5 +34,14 @@ proc.once('exit', common.mustCall(() => {
     assert(traces.some((trace) =>
       trace.cat === '__metadata' && trace.name === 'version' &&
         trace.args.node === process.versions.node));
+    if (!common.isSunOS) {
+      // Changing process.title is currently unsupported on SunOS/SmartOS
+      assert(traces.some((trace) =>
+        trace.cat === '__metadata' && trace.name === 'process_name' &&
+          trace.args.name === 'foo'));
+      assert(traces.some((trace) =>
+        trace.cat === '__metadata' && trace.name === 'process_name' &&
+          trace.args.name === 'bar'));
+    }
   }));
 }));