amitsaha · July 16, 2021 23:13 · Jul 16, 2021 · Jul 16, 2021 · Jul 16, 2021
diff --git a/doc.md b/doc.md
@@ -71,3 +71,8 @@ func (c *conn) serve(ctx context.Context) {
 However, when I make a request to the /2 endpoint, there is no log of the panic as explained by the documentation 
 of `ErrAbortHandler`.
 
+Due to the recovery mechanism setup, the server process doesn't get aborted and the panic details are logged.
+
+You can also write a middleware to setup your own recovery mechanism so that the stdlib's recovery mechanism is not 
+triggered at all.
+
diff --git a/comments.md → doc.md b/comments.md → doc.md
@@ -1,3 +1,28 @@
+Consider a test HTTP server in Go:
+
+```
+package main
+
+import "net/http"
+
+func myHandler1(w http.ResponseWriter, r *http.Request) {
+	panic("I panicked")
+}
+
+func myHandler2(w http.ResponseWriter, r *http.Request) {
+	panic(http.ErrAbortHandler)
+}
+
+func main() {
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/1", myHandler1)
+	mux.HandleFunc("/2", myHandler2)
+
+	http.ListenAndServe(":8080", mux)
+}
+```
+
 When i make a request to the /1 endpoint, on the server i see this:
 
 ```
@@ -45,3 +70,4 @@ func (c *conn) serve(ctx context.Context) {
 
 However, when I make a request to the /2 endpoint, there is no log of the panic as explained by the documentation 
 of `ErrAbortHandler`.
+
diff --git a/main.go b/main.go
@@ -1,20 +0,0 @@
-package main
-
-import "net/http"
-
-func myHandler1(w http.ResponseWriter, r *http.Request) {
-	panic("I panicked")
-}
-
-func myHandler2(w http.ResponseWriter, r *http.Request) {
-	panic(http.ErrAbortHandler)
-}
-
-func main() {
-
-	mux := http.NewServeMux()
-	mux.HandleFunc("/1", myHandler1)
-	mux.HandleFunc("/2", myHandler2)
-
-	http.ListenAndServe(":8080", mux)
-}

diff --git a/comments.md b/comments.md
@@ -0,0 +1,47 @@
+When i make a request to the /1 endpoint, on the server i see this:
+
+```
+2021/07/17 09:04:07 http: panic serving [::1]:52336: I panicked
+goroutine 4 [running]:
+net/http.(*conn).serve.func1(0x1400010aa00)
+	/usr/local/go/src/net/http/server.go:1824 +0x108
+panic(0x102672ca0, 0x1026c3590)
+	/usr/local/go/src/runtime/panic.go:971 +0x3f4
+main.myHandler1(0x1026cbb30, 0x140001420e0, 0x1400014e000)
+	/Users/echorand/work/github.com/amitsaha/tmp/server.go:6 +0x38
+net/http.HandlerFunc.ServeHTTP(0x1026c2790, 0x1026cbb30, 0x140001420e0, 0x1400014e000)
+	/usr/local/go/src/net/http/server.go:2069 +0x40
+net/http.(*ServeMux).ServeHTTP(0x14000024200, 0x1026cbb30, 0x140001420e0, 0x1400014e000)
+	/usr/local/go/src/net/http/server.go:2448 +0x190
+net/http.serverHandler.ServeHTTP(0x14000142000, 0x1026cbb30, 0x140001420e0, 0x1400014e000)
+	/usr/local/go/src/net/http/server.go:2887 +0xbc
+net/http.(*conn).serve(0x1400010aa00, 0x1026cc000, 0x14000024280)
+	/usr/local/go/src/net/http/server.go:1952 +0x710
+created by net/http.(*Server).Serve
+	/usr/local/go/src/net/http/server.go:3013 +0x308
+```
+
+The recovery is happening here in the stdlib's [code](https://golang.org/src/net/http/server.go?s=99233:99288#L1797):
+
+```
+// Serve a new connection.
+func (c *conn) serve(ctx context.Context) {
+	c.remoteAddr = c.rwc.RemoteAddr().String()
+	ctx = context.WithValue(ctx, LocalAddrContextKey, c.rwc.LocalAddr())
+	defer func() {
+		if err := recover(); err != nil && err != ErrAbortHandler {
+			const size = 64 << 10
+			buf := make([]byte, size)
+			buf = buf[:runtime.Stack(buf, false)]
+			c.server.logf("http: panic serving %v: %v\n%s", c.remoteAddr, err, buf)
+		}
+		if !c.hijacked() {
+			c.close()
+			c.setState(c.rwc, StateClosed, runHooks)
+		}
+	}()
+
+```
+
+However, when I make a request to the /2 endpoint, there is no log of the panic as explained by the documentation 
+of `ErrAbortHandler`.
diff --git a/main.go b/main.go
@@ -0,0 +1,20 @@
+package main
+
+import "net/http"
+
+func myHandler1(w http.ResponseWriter, r *http.Request) {
+	panic("I panicked")
+}
+
+func myHandler2(w http.ResponseWriter, r *http.Request) {
+	panic(http.ErrAbortHandler)
+}
+
+func main() {
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/1", myHandler1)
+	mux.HandleFunc("/2", myHandler2)
+
+	http.ListenAndServe(":8080", mux)
+}