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

doc/api/diagnostics_channel.md

@@ -1268,6 +1268,13 @@ Emitted when an error occurs during the processing of a stream on the server.
 
 Emitted when a stream is sent on the server.
 
+`http2.server.stream.close`
+
+* `stream` {ServerHttp2Stream}
+
+Emitted when a stream is closed on the server. The HTTP/2 error code used when
+closing the stream can be retrieved using the `stream.rstCode` property.
+
 #### Modules
 
 > Stability: 1 - Experimental

lib/internal/http2/core.js

@@ -196,6 +196,7 @@ const onServerStreamCreatedChannel = dc.channel('http2.server.stream.created');
 const onServerStreamStartChannel = dc.channel('http2.server.stream.start');
 const onServerStreamErrorChannel = dc.channel('http2.server.stream.error');
 const onServerStreamFinishChannel = dc.channel('http2.server.stream.finish');
+const onServerStreamCloseChannel = dc.channel('http2.server.stream.close');
 
 let debug = require('internal/util/debuglog').debuglog('http2', (fn) => {
   debug = fn;
@@ -2011,9 +2012,12 @@ function closeStream(stream, code, rstStreamStatus = kSubmitRstStream) {
       stream.once('finish', finishFn);
   }
 
-  if (type === NGHTTP2_SESSION_CLIENT &&
-      onClientStreamCloseChannel.hasSubscribers) {
-    onClientStreamCloseChannel.publish({ stream });
+  if (type === NGHTTP2_SESSION_CLIENT) {
+    if (onClientStreamCloseChannel.hasSubscribers) {
+      onClientStreamCloseChannel.publish({ stream });
+    }
+  } else if (onServerStreamCloseChannel.hasSubscribers) {
+    onServerStreamCloseChannel.publish({ stream });
   }
 }
 

test/parallel/test-diagnostics-channel-http2-server-stream-close-error.js

@@ -0,0 +1,52 @@
+'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.close' channel when
+// a ServerHttp2Stream is destroyed because of an error.
+
+const assert = require('assert');
+const dc = require('diagnostics_channel');
+const http2 = require('http2');
+const { Duplex } = require('stream');
+
+dc.subscribe('http2.server.stream.close', common.mustCall(({ stream }) => {
+  // 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.strictEqual(stream.closed, true);
+  assert.strictEqual(stream.destroyed, true);
+
+  assert.strictEqual(stream.rstCode, http2.constants.NGHTTP2_INTERNAL_ERROR);
+}));
+
+const server = http2.createServer();
+
+server.on('stream', common.mustCall((stream) => {
+  let expectedError;
+
+  stream.on('error', common.mustCall((err) => {
+    assert.strictEqual(err, expectedError);
+  }));
+
+  expectedError = new Error('HTTP/2 server stream error');
+  stream.destroy(expectedError);
+}));
+
+server.listen(0, common.mustCall(() => {
+  const port = server.address().port;
+  const client = http2.connect(`http://localhost:${port}`);
+
+  const stream = client.request({});
+  stream.on('error', common.mustCall((err) => {
+    assert.strictEqual(err.code, 'ERR_HTTP2_STREAM_ERROR');
+
+    client.close();
+    server.close();
+  }));
+}));

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

@@ -0,0 +1,63 @@
+'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.close' channel when
+// ServerHttp2Streams created by these actions are closed:
+// - 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 serverHttp2StreamCloseCount = 2;
+
+dc.subscribe('http2.server.stream.close', common.mustCall(({ stream }) => {
+  // 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.strictEqual(stream.closed, true);
+  assert.strictEqual(stream.destroyed, false);
+
+  assert.strictEqual(stream.rstCode, http2.constants.NGHTTP2_NO_ERROR);
+}, serverHttp2StreamCloseCount));
+
+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(serverHttp2StreamCloseCount, () => {
+    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();
+    }));
+  }));
+}));