From 6b1a9761812c2f373e52684ae4be8fb939e589b7 Mon Sep 17 00:00:00 2001
From: Marcos Casagrande <marcoscvp90@gmail.com>
Date: Thu, 10 Aug 2023 19:45:55 +0200
Subject: perf(ext/http): use ServeHandlerInfo class instead of object literal
 (#20122)
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This PR improves performance of `Deno.Serve` when providing `info`
argument by creating `ServeHandlerInfo` class instead of creating an
object literal with a getter on every request.

```js
Deno.serve((_req, info) => new Response(info.remoteAddr.transport) });
```

### Benchmarks
```
wrk -d 10s --latency http://127.0.0.1:4500
Running 10s test @ http://127.0.0.1:4500
  2 threads and 10 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    42.34us   16.30us   1.66ms   95.88%
    Req/Sec   118.17k     2.95k  127.38k    76.73%
  Latency Distribution
     50%   38.00us
     75%   41.00us
     90%   56.00us
     99%   83.00us
  2375298 requests in 10.10s, 319.40MB read
Requests/sec: 235177.04
Transfer/sec:     31.62MB
```

**main**
```
wrk -d 10s --latency http://127.0.0.1:4500
Running 10s test @ http://127.0.0.1:4500
  2 threads and 10 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    78.86us  211.06us   3.58ms   96.52%
    Req/Sec   105.90k     4.35k  117.41k    78.22%
  Latency Distribution
     50%   41.00us
     75%   53.00us
     90%   62.00us
     99%    1.18ms
  2127534 requests in 10.10s, 286.09MB read
Requests/sec: 210647.49
Transfer/sec:     28.33MB
```

```
cpu: 13th Gen Intel(R) Core(TM) i9-13900H
runtime: deno 1.36.0 (x86_64-unknown-linux-gnu)

benchmark                 time (avg)        iter/s             (min … max)       p75       p99      p995
-------------------------------------------------------------------------- -----------------------------
new ServeHandlerInfo      3.43 ns/iter 291,508,889.3    (3.07 ns … 12.21 ns)   3.42 ns   3.84 ns   3.87 ns
{} with getter           133.84 ns/iter   7,471,528.9   (92.9 ns … 458.95 ns) 132.45 ns 364.96 ns 429.43 ns
```


----
### Drawbacks:

`.remoteAddr` is now not enumerable

```
ServeHandlerInfo {}
```
vs
```
{ remoteAddr: [Getter] }
```
It'll break any code trying to iterate through `info` keys (Doubt
there's anyone doing it though)

```js
Deno.serve((req, info) => {
  console.log(Object.keys(info).length === 0) // true;
  return new Response("yes");
});
---
 ext/http/00_serve.js | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

(limited to 'ext/http/00_serve.js')

diff --git a/ext/http/00_serve.js b/ext/http/00_serve.js
index af4353e0e..3447f48e2 100644
--- a/ext/http/00_serve.js
+++ b/ext/http/00_serve.js
@@ -369,6 +369,16 @@ class CallbackContext {
   }
 }
 
+class ServeHandlerInfo {
+  #inner = null;
+  constructor(inner) {
+    this.#inner = inner;
+  }
+  get remoteAddr() {
+    return this.#inner.remoteAddr;
+  }
+}
+
 function fastSyncResponseOrStream(req, respBody) {
   if (respBody === null || respBody === undefined) {
     // Don't set the body
@@ -535,11 +545,10 @@ function mapToCallback(context, callback, onError) {
         if (hasOneCallback) {
           response = await callback(request);
         } else {
-          response = await callback(request, {
-            get remoteAddr() {
-              return innerRequest.remoteAddr;
-            },
-          });
+          response = await callback(
+            request,
+            new ServeHandlerInfo(innerRequest),
+          );
         }
       } else {
         response = await callback();
-- 
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