refactor: rename context key variables to meaningful names

api.handlers.book.go

@@ -17,7 +17,7 @@ func (api *APIHandler) Index(w http.ResponseWriter, r *http.Request, _ httproute
 
 // Status provides basics details about the application to the public users.
 func (api *APIHandler) Status(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
 	if err := json.NewEncoder(w).Encode(
 		map[string]interface{}{
@@ -32,7 +32,7 @@ func (api *APIHandler) Status(w http.ResponseWriter, r *http.Request, _ httprout
 
 func (api *APIHandler) CreateBook(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
 	book := Book{}
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	err := DecodeCreateOrUpdateBookRequestBody(r, &book)
 	if err != nil {
 		api.logger.Error("failed to create book", zap.String("request.id", requestID), zap.Error(err))
@@ -74,7 +74,7 @@ func (api *APIHandler) CreateBook(w http.ResponseWriter, r *http.Request, _ http
 
 //nolint:bodyclose
 func (api *APIHandler) GetAllBooks(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	// this block could be moved into the TimeoutMiddleware and remove SetWriteDeadline and
 	// ReadWriteDeadline methods from *CustomResponseWriter object because that middleware
 	// is called before the stats middleware which wraps the native ResponseWriter.
@@ -101,7 +101,7 @@ func (api *APIHandler) GetAllBooks(w http.ResponseWriter, r *http.Request, _ htt
 }
 
 func (api *APIHandler) GetOneBook(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	id := ps.ByName("id")
 	if ok := api.idsHandler.IsValid(id, BookIDPrefix); !ok {
 		api.logger.Error("book id provided is not valid", zap.String("book.id", id), zap.String("request.id", requestID))
@@ -136,7 +136,7 @@ func (api *APIHandler) GetOneBook(w http.ResponseWriter, r *http.Request, ps htt
 }
 
 func (api *APIHandler) DeleteOneBook(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	id := ps.ByName("id")
 	if ok := api.idsHandler.IsValid(id, BookIDPrefix); !ok {
 		api.logger.Error("book id provided is not valid", zap.String("book.id", id), zap.String("request.id", requestID))
@@ -190,7 +190,7 @@ func (api *APIHandler) DeleteOneBook(w http.ResponseWriter, r *http.Request, ps
 
 func (api *APIHandler) UpdateBook(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
 	var book Book
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	err := DecodeCreateOrUpdateBookRequestBody(r, &book)
 	if err != nil {
 		api.logger.Error("failed to update book", zap.String("request.id", requestID), zap.Error(err))

api.handlers.ops.go

@@ -67,7 +67,7 @@ func GetMemStats(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
 
 // RunGC forces the run of the garbage collector asynchronously.
 func (api *APIHandler) RunGC(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	go runtime.GC()
 	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
 	if err := json.NewEncoder(w).Encode(
@@ -82,7 +82,7 @@ func (api *APIHandler) RunGC(w http.ResponseWriter, r *http.Request, _ httproute
 // FreeOSMemory forces the garbage collector to and tries to returns the memory
 // back to the operating system in an asynchronous fashion.
 func (api *APIHandler) FreeOSMemory(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	go debug.FreeOSMemory()
 	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
 	if err := json.NewEncoder(w).Encode(
@@ -98,7 +98,7 @@ func (api *APIHandler) FreeOSMemory(w http.ResponseWriter, r *http.Request, _ ht
 // The stats returns by this handler do not contain the ops request which triggered that.
 // That is why we remove 1 from the called field value in order to match the status stats.
 func (api *APIHandler) GetStatistics(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
 	api.stats.mu.RLock()
 	maintenanceModeStartedTime := api.mode.started.String()
@@ -131,7 +131,7 @@ func (api *APIHandler) GetStatistics(w http.ResponseWriter, r *http.Request, _ h
 
 // GetConfigs serves current in-use configurations/settings.
 func (api *APIHandler) GetConfigs(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
 	if err := json.NewEncoder(w).Encode(
 		map[string]interface{}{
@@ -147,7 +147,7 @@ func (api *APIHandler) GetConfigs(w http.ResponseWriter, r *http.Request, _ http
 // Enable the maintenance mode : /ops/maintenance?status=enable&msg=message-to-be-displayed-to-users
 // Disable the maintenance mode: /ops/maintenance?status=disable
 func (api *APIHandler) Maintenance(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
 	var response map[string]interface{}
 	var logger *zap.Logger
@@ -201,7 +201,7 @@ func (api *APIHandler) Maintenance(w http.ResponseWriter, r *http.Request, ps ht
 
 // ClearBooksCache deletes all books entries from the primary storage (cache).
 func (api *APIHandler) ClearBooksCache(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
-	requestID := GetValueFromContext(r.Context(), ContextRequestID)
+	requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 	go api.bookService.DeleteAll(r.Context(), requestID)
 	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
 	if err := json.NewEncoder(w).Encode(

api.middlewares.go

@@ -55,7 +55,7 @@ func (api *APIHandler) StatsMiddleware(next httprouter.Handle) httprouter.Handle
 // AddLoggerMiddleware creates a logger with pre-populated fields for each request.
 func (api *APIHandler) AddLoggerMiddleware(next httprouter.Handle) httprouter.Handle {
 	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
-		requestID := GetValueFromContext(r.Context(), ContextRequestID)
+		requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 		requestNum := GetRequestNumberFromContext(r.Context())
 		logger := api.logger.With(
 			zap.String("request.id", requestID),
@@ -67,7 +67,7 @@ func (api *APIHandler) AddLoggerMiddleware(next httprouter.Handle) httprouter.Ha
 			zap.String("request.referer", r.Referer()),
 		)
 
-		ctx := context.WithValue(r.Context(), ContextRequestLogger, logger)
+		ctx := context.WithValue(r.Context(), LoggerContextKey, logger)
 		r = r.WithContext(ctx)
 		next(w, r, ps)
 	}
@@ -94,7 +94,7 @@ func (api *APIHandler) MaintenanceModeMiddleware(next httprouter.Handle) httprou
 // new value to the request context to be used during logging as `request.num` field.
 func (api *APIHandler) RequestsCounterMiddleware(next httprouter.Handle) httprouter.Handle {
 	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
-		ctx := context.WithValue(r.Context(), ContextRequestNumber, atomic.AddUint64(&api.stats.called, 1))
+		ctx := context.WithValue(r.Context(), RequestNumberContextKey, atomic.AddUint64(&api.stats.called, 1))
 		r = r.WithContext(ctx)
 		next(w, r, ps)
 	}
@@ -104,7 +104,7 @@ func (api *APIHandler) RequestsCounterMiddleware(next httprouter.Handle) httprou
 func (api *APIHandler) RequestIDMiddleware(next httprouter.Handle) httprouter.Handle {
 	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
 		requestID := api.idsHandler.Generate(RequestIDPrefix)
-		ctx := context.WithValue(r.Context(), ContextRequestID, requestID)
+		ctx := context.WithValue(r.Context(), RequestIDContextKey, requestID)
 		r = r.WithContext(ctx)
 		next(w, r, ps)
 	}
@@ -126,7 +126,7 @@ func (api *APIHandler) PanicRecoveryMiddleware(next httprouter.Handle) httproute
 	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
 		recovery := func() {
 			if err := recover(); err != nil {
-				requestID := GetValueFromContext(r.Context(), ContextRequestID)
+				requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 				api.logger.Error("panic occurred", zap.String("request.id", requestID), zap.Any("error", err))
 				errResp := NewAPIError(requestID, http.StatusInternalServerError, "failed to process the request.", struct{}{})
 				if err := WriteErrorResponse(r.Context(), w, errResp); err != nil {
@@ -144,7 +144,7 @@ func (api *APIHandler) PanicRecoveryMiddleware(next httprouter.Handle) httproute
 // header to notify the final handler to not perform any action towards the client.
 func (api *APIHandler) TimeoutMiddleware(next httprouter.Handle) httprouter.Handle {
 	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
-		requestID := GetValueFromContext(r.Context(), ContextRequestID)
+		requestID := GetValueFromContext(r.Context(), RequestIDContextKey)
 		logger := api.GetLoggerFromContext(r.Context())
 		timeout := api.GetTimeout(r)
 		ctx, cancel := context.WithTimeout(r.Context(), timeout)

helpers.common.go

@@ -18,11 +18,11 @@ type (
 )
 
 const (
-	BookIDPrefix         string     = "b"
-	RequestIDPrefix      string     = "r"
-	ContextRequestID     ContextKey = "request.id"
-	ContextRequestNumber ContextKey = "request.number"
-	ConnContextKey       ContextKey = "http-conn"
+	BookIDPrefix            string     = "b"
+	RequestIDPrefix         string     = "r"
+	RequestIDContextKey     ContextKey = "request.id"
+	RequestNumberContextKey ContextKey = "request.number"
+	ConnContextKey          ContextKey = "http-conn"
 )
 
 func (m missingFieldError) Error() string {
@@ -41,7 +41,7 @@ func GetValueFromContext(ctx context.Context, contextKey ContextKey) string {
 // GetRequestNumberFromContext returns the request number set in
 // the context. if not previously set then it returns 0.
 func GetRequestNumberFromContext(ctx context.Context) uint64 {
-	if val := ctx.Value(ContextRequestNumber); val != nil {
+	if val := ctx.Value(RequestNumberContextKey); val != nil {
 		return val.(uint64)
 	}
 	return 0

helpers.logging.go

@@ -12,7 +12,7 @@ import (
 )
 
 const (
-	ContextRequestLogger ContextKey = "request.logger"
+	LoggerContextKey ContextKey = "request.logger"
 )
 
 // SetupLogging is a helper function that initializes the logging module.
@@ -68,7 +68,7 @@ func SetupLogging(config *Config, logFile *os.File, clock TickerClocker) (*zap.L
 // GetLoggerFromCtx retrieves previously set logger from the context and returns it.
 // If the logger can't be retrieved it will return the initial logger of the App.
 func (api *APIHandler) GetLoggerFromContext(ctx context.Context) *zap.Logger {
-	value := ctx.Value(ContextRequestLogger)
+	value := ctx.Value(LoggerContextKey)
 	if value != nil {
 		return value.(*zap.Logger)
 	}

tests.middlewares_test.go

@@ -123,7 +123,7 @@ func TestMaintenanceModeMiddleware(t *testing.T) {
 		ts := NewMockClocker().Now()
 		api.mode.started = ts
 		api.mode.reason = "ongoing maintenance."
-		req = req.WithContext(context.WithValue(req.Context(), ContextRequestID, "abc"))
+		req = req.WithContext(context.WithValue(req.Context(), RequestIDContextKey, "abc"))
 		wrapped := api.MaintenanceModeMiddleware(handler)
 		wrapped(w, req, nil)
 		// target handler will not be called but the maintenance handler must kick-in.
@@ -147,7 +147,7 @@ func TestRequestIDMiddleware(t *testing.T) {
 	var id string
 	handler := func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
 		called = true
-		id = GetValueFromContext(req.Context(), ContextRequestID)
+		id = GetValueFromContext(req.Context(), RequestIDContextKey)
 	}
 	wrapped := api.RequestIDMiddleware(handler)
 	wrapped(w, req, nil)
@@ -166,7 +166,7 @@ func TestAddLoggerMiddleware(t *testing.T) {
 	var value interface{}
 	handler := func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
 		called = true
-		value = req.Context().Value(ContextRequestLogger)
+		value = req.Context().Value(LoggerContextKey)
 	}
 	wrapped := api.AddLoggerMiddleware(handler)
 	wrapped(w, req, nil)