http2: add diagnostics channel 'http2.server.stream.start'

Signed-off-by: Darshan Sen <raisinten@gmail.com> PR-URL: #58449 Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>

Author: RaisinTen

doc/api/diagnostics_channel.md

@@ -1246,6 +1246,13 @@ closing the stream can be retrieved using the `stream.rstCode` property.
 
 Emitted when a stream is created on the server.
 
+`http2.server.stream.start`
+
+* `stream` {ServerHttp2Stream}
+* `headers` {HTTP/2 Headers Object}
+
+Emitted when a stream is started on the server.
+
 #### Modules
 
 > Stability: 1 - Experimental

lib/internal/http2/core.js

@@ -191,6 +191,7 @@ const onClientStreamErrorChannel = dc.channel('http2.client.stream.error');
 const onClientStreamFinishChannel = dc.channel('http2.client.stream.finish');
 const onClientStreamCloseChannel = dc.channel('http2.client.stream.close');
 const onServerStreamCreatedChannel = dc.channel('http2.server.stream.created');
+const onServerStreamStartChannel = dc.channel('http2.server.stream.start');
 
 let debug = require('internal/util/debuglog').debuglog('http2', (fn) => {
  debug = fn;
@@ -373,6 +374,12 @@ function onSessionHeaders(handle, id, cat, flags, headers, sensitiveHeaders) {
  headers: obj,
  });
  }
+ if (onServerStreamStartChannel.hasSubscribers) {
+ onServerStreamStartChannel.publish({
+ stream,
+ headers: obj,
+ });
+ }
  if (endOfStream) {
  stream.push(null);
  }
@@ -2838,7 +2845,16 @@ class ServerHttp2Stream extends Http2Stream {
  if (headRequest)
  stream[kState].flags |= STREAM_FLAGS_HEAD_REQUEST;
 
- process.nextTick(callback, null, stream, headers, 0);
+ process.nextTick(() => {
+ if (onServerStreamStartChannel.hasSubscribers) {
+ onServerStreamStartChannel.publish({
+ stream,
+ headers,
+ });
+ }
+
+ callback(null, stream, headers, 0);
+ });
 
  if (onServerStreamCreatedChannel.hasSubscribers) {
  onServerStreamCreatedChannel.publish({

test/parallel/test-diagnostics-channel-http2-server-stream-created-start-timing.js

@@ -0,0 +1,65 @@
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+ common.skip('missing crypto');
+
+// This test ensures that the built-in HTTP/2 diagnostics channels are reporting
+// the diagnostics messages for the 'http2.server.stream.start' channel only
+// after the 'http2.server.stream.created' channel.
+
+const Countdown = require('../common/countdown');
+const assert = require('assert');
+const dc = require('diagnostics_channel');
+const http2 = require('http2');
+
+const serverHttp2StreamCreationCount = 2;
+
+const map = {};
+
+dc.subscribe('http2.server.stream.created', common.mustCall(({ stream, headers }) => {
+ map[stream.id] = { ...map[stream.id], 'createdTime': process.hrtime.bigint() };
+}, serverHttp2StreamCreationCount));
+
+dc.subscribe('http2.server.stream.start', common.mustCall(({ stream, headers }) => {
+ map[stream.id] = { ...map[stream.id], 'startTime': process.hrtime.bigint() };
+}, serverHttp2StreamCreationCount));
+
+const server = http2.createServer();
+server.on('stream', common.mustCall((stream) => {
+ stream.respond();
+ stream.end();
+
+ stream.pushStream({}, common.mustSucceed((pushStream) => {
+ pushStream.respond();
+ pushStream.end();
+ }));
+}));
+
+server.listen(0, common.mustCall(() => {
+ const port = server.address().port;
+ const client = http2.connect(`http://localhost:${port}`);
+
+ const countdown = new Countdown(serverHttp2StreamCreationCount, () => {
+ client.close();
+ server.close();
+
+ const timings = Object.values(map);
+ assert.strictEqual(timings.length, serverHttp2StreamCreationCount);
+
+ for (const { createdTime, startTime } of timings) {
+ assert.ok(createdTime < startTime);
+ }
+ });
+
+ const stream = client.request({});
+ stream.on('response', common.mustCall(() => {
+ countdown.dec();
+ }));
+
+ client.on('stream', common.mustCall((pushStream) => {
+ pushStream.on('push', common.mustCall(() => {
+ countdown.dec();
+ }));
+ }));
+}));

test/parallel/test-diagnostics-channel-http2-server-stream-start.js

@@ -0,0 +1,60 @@
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+ common.skip('missing crypto');
+
+// This test ensures that the built-in HTTP/2 diagnostics channels are reporting
+// the diagnostics messages for the 'http2.server.stream.start' channel when
+// ServerHttp2Streams are started by both:
+// - in response to an incoming 'stream' event from the client
+// - the server calling ServerHttp2Stream#pushStream()
+
+const Countdown = require('../common/countdown');
+const assert = require('assert');
+const dc = require('diagnostics_channel');
+const http2 = require('http2');
+const { Duplex } = require('stream');
+
+const serverHttp2StreamCreationCount = 2;
+
+dc.subscribe('http2.server.stream.start', common.mustCall(({ stream, headers }) => {
+ // Since ServerHttp2Stream is not exported from any module, this just checks
+ // if the stream is an instance of Duplex and the constructor name is
+ // 'ServerHttp2Stream'.
+ assert.ok(stream instanceof Duplex);
+ assert.strictEqual(stream.constructor.name, 'ServerHttp2Stream');
+ assert.ok(headers && !Array.isArray(headers) && typeof headers === 'object');
+}, serverHttp2StreamCreationCount));
+
+const server = http2.createServer();
+server.on('stream', common.mustCall((stream) => {
+ stream.respond();
+ stream.end();
+
+ stream.pushStream({}, common.mustSucceed((pushStream) => {
+ pushStream.respond();
+ pushStream.end();
+ }));
+}));
+
+server.listen(0, common.mustCall(() => {
+ const port = server.address().port;
+ const client = http2.connect(`http://localhost:${port}`);
+
+ const countdown = new Countdown(serverHttp2StreamCreationCount, () => {
+ client.close();
+ server.close();
+ });
+
+ const stream = client.request({});
+ stream.on('response', common.mustCall(() => {
+ countdown.dec();
+ }));
+
+ client.on('stream', common.mustCall((pushStream) => {
+ pushStream.on('push', common.mustCall(() => {
+ countdown.dec();
+ }));
+ }));
+}));