From 329bbb7cb873d32b54c227b52c89e95c8bfdfd50 Mon Sep 17 00:00:00 2001
From: youngjun827 <youngjunjoo827@gmail.com>
Date: Tue, 7 Nov 2023 17:38:58 -0500
Subject: [PATCH] refactor(web): Improve error handling and shutdown logic in
 web framework

---
 business/web/v1/response/response.go | 34 ++++++++++++++++++++++++++++
 foundation/web/shutdown.go           | 26 +++++++++++++++++++++
 foundation/web/web.go                | 25 +++++++++++++++++++-
 3 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 business/web/v1/response/response.go
 create mode 100644 foundation/web/shutdown.go

diff --git a/business/web/v1/response/response.go b/business/web/v1/response/response.go
new file mode 100644
index 0000000..43508b4
--- /dev/null
+++ b/business/web/v1/response/response.go
@@ -0,0 +1,34 @@
+package response
+
+import "errors"
+
+type ErrorDocument struct {
+	Error  string            `json:"error"`
+	Fields map[string]string `json:"fields,omitempty"`
+}
+
+type Error struct {
+	Err    error
+	Status int
+}
+
+func NewError(err error, status int) error {
+	return &Error{err, status}
+}
+
+func (re *Error) Error() string {
+	return re.Err.Error()
+}
+
+func IsError(err error) bool {
+	var re *Error
+	return errors.As(err, &re)
+}
+
+func GetError(err error) *Error {
+	var re *Error
+	if !errors.As(err, &re) {
+		return nil
+	}
+	return re
+}
\ No newline at end of file
diff --git a/foundation/web/shutdown.go b/foundation/web/shutdown.go
new file mode 100644
index 0000000..120e6c7
--- /dev/null
+++ b/foundation/web/shutdown.go
@@ -0,0 +1,26 @@
+package web
+
+import "errors"
+
+// shutdownError is a type used to help with the graceful termination of the service.
+type shutdownError struct {
+	Message string
+}
+
+// NewShutdownError returns an error that causes the framework to signal
+// a graceful shutdown.
+func NewShutdownError(message string) error {
+	return &shutdownError{message}
+}
+
+// Error is the implementation of the error interface.
+func (se *shutdownError) Error() string {
+	return se.Message
+}
+
+// IsShutdown checks to see if the shutdown error is contained
+// in the specified error value.
+func IsShutdown(err error) bool {
+	var se *shutdownError
+	return errors.As(err, &se)
+}
\ No newline at end of file
diff --git a/foundation/web/web.go b/foundation/web/web.go
index e0b8fd2..c8ff39e 100644
--- a/foundation/web/web.go
+++ b/foundation/web/web.go
@@ -3,8 +3,10 @@ package web
 
 import (
 	"context"
+	"errors"
 	"net/http"
 	"os"
+	"syscall"
 	"time"
 
 	"github.com/go-chi/chi/v5"
@@ -28,6 +30,22 @@ func NewApp(shutdown chan os.Signal, mw ...Middleware) *App {
     }
 }
 
+func (a *App) SignalShutdown() {
+	a.shutdown <- syscall.SIGTERM
+}
+
+func validateShutdown(err error) bool {
+	switch {
+	case errors.Is(err, syscall.EPIPE):
+		return false
+
+	case errors.Is(err, syscall.ECONNRESET):
+		return false
+	}
+
+	return true
+}
+
 func HandlerAdapter(handler Handler) http.HandlerFunc {
     return func(w http.ResponseWriter, r *http.Request) {
         err := handler(r.Context(), w, r)
@@ -50,10 +68,15 @@ func (a *App) Handle(method string, path string, handler Handler, mw ...Middlewa
 		ctx = SetValues(ctx, &v)
 		err := wrappedHandler(ctx, w, r)
         if err != nil {
-            http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+			if validateShutdown(err) {
+				a.SignalShutdown()
+				return err
+			}
         }
         return nil
     }
 
     a.Mux.MethodFunc(method, path, HandlerAdapter(customHandler))
 }
+
+