feat(middleware): Add a recovery middleware

middleware/recovery.go

@@ -0,0 +1,54 @@
+package middleware
+
+import (
+	"fmt"
+	"net/http"
+
+	"git.dev.m-and-m.ovh/mderasse/gocommon/commonctx"
+)
+
+type recoveryFuncSignature func(w http.ResponseWriter, r *http.Request)
+
+type recoveryMiddleware struct {
+	handler  http.Handler
+	respFunc recoveryFuncSignature
+}
+
+func (rm *recoveryMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	defer func() {
+		if err := recover(); err != nil {
+
+			// log the error
+			log := commonctx.GetLogger(r.Context())
+			if log == nil {
+				fmt.Print("Impossible to log the panic as the logger is not part of the context\n")
+			} else {
+				// Probably have to catch a stacktrace + Info about the error
+				log.Error("A Panic happened and has been caught")
+			}
+			// execute the recovery function
+			rm.respFunc(w, r)
+		}
+	}()
+	rm.handler.ServeHTTP(w, r)
+}
+
+// NewRecoveryMiddleware will declare a new middleware on the provided handler. It will recover any panic and log it.
+// By default, the middleware will return a default error object in json with a 500 Http code. That can be overide by providing a recoveryFunc.
+func NewRecoveryMiddleware(h http.Handler, recoveryFunc recoveryFuncSignature) *recoveryMiddleware {
+	recovery := &recoveryMiddleware{
+		handler:  h,
+		respFunc: recoveryFunc,
+	}
+	if recovery.respFunc == nil {
+		recovery.respFunc = func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("X-Content-Type-Options", "nosniff")
+			w.Header().Set("Content-Type", "application/json; charset=utf-8")
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(
+				fmt.Sprintf("{\"code\":%d,\"message\":\"An error happened during the execution of your request.\"}", http.StatusInternalServerError),
+			))
+		}
+	}
+	return recovery
+}