[#260] Refactor api/auth/center.go

Move the Center interface to middleware package where it's used

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

api/middleware/auth.go

@@ -1,21 +1,49 @@
 package middleware
 
 import (
+	stderrors "errors"
 	"net/http"
+	"time"
 
-	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/auth"
 	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/errors"
+	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/creds/accessbox"
 	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/internal/logs"
 	"go.uber.org/zap"
 )
 
-func Auth(center auth.Center, log *zap.Logger) Func {
+type (
+	// Box contains access box and additional info.
+	Box struct {
+		AccessBox   *accessbox.Box
+		ClientTime  time.Time
+		AuthHeaders *AuthHeader
+	}
+
+	// Center is a user authentication interface.
+	Center interface {
+		// Authenticate validate and authenticate request.
+		// Must return ErrNoAuthorizationHeader if auth header is missed.
+		Authenticate(request *http.Request) (*Box, error)
+	}
+
+	//nolint:revive
+	AuthHeader struct {
+		AccessKeyID string
+		Region      string
+		SignatureV4 string
+	}
+)
+
+// ErrNoAuthorizationHeader is returned for unauthenticated requests.
+var ErrNoAuthorizationHeader = stderrors.New("no authorization header")
+
+func Auth(center Center, log *zap.Logger) Func {
 	return func(h http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			ctx := r.Context()
 			box, err := center.Authenticate(r)
 			if err != nil {
-				if err == auth.ErrNoAuthorizationHeader {
+				if err == ErrNoAuthorizationHeader {
 					reqLogOrDefault(ctx, log).Debug(logs.CouldntReceiveAccessBoxForGateKeyRandomKeyWillBeUsed)
 				} else {
 					reqLogOrDefault(ctx, log).Error(logs.FailedToPassAuthentication, zap.Error(err))