From b2f7d285687beaf5ce9274d39115fa4140c4851f Mon Sep 17 00:00:00 2001
From: Quentin McGaw <quentin.mcgaw@gmail.com>
Date: Wed, 15 Nov 2023 10:05:23 +0000
Subject: [PATCH] chore(pkg/middlewares): use settings for cache and filter
 constructors (future proofing for compatibility)

---
 pkg/middlewares/cache/middleware.go  | 13 ++++++++++---
 pkg/middlewares/cache/settings.go    | 22 ++++++++++++++++++++++
 pkg/middlewares/filter/middleware.go | 13 ++++++++++---
 pkg/middlewares/filter/settings.go   | 22 ++++++++++++++++++++++
 4 files changed, 64 insertions(+), 6 deletions(-)
 create mode 100644 pkg/middlewares/cache/settings.go
 create mode 100644 pkg/middlewares/filter/settings.go

diff --git a/pkg/middlewares/cache/middleware.go b/pkg/middlewares/cache/middleware.go
index 3707f53c..4debe740 100644
--- a/pkg/middlewares/cache/middleware.go
+++ b/pkg/middlewares/cache/middleware.go
@@ -1,6 +1,8 @@
 package cache
 
 import (
+	"fmt"
+
 	"github.com/miekg/dns"
 	"github.com/qdm12/dns/v2/internal/stateful"
 )
@@ -9,10 +11,15 @@ type Middleware struct {
 	cache Cache
 }
 
-func New(cache Cache) *Middleware {
-	return &Middleware{
-		cache: cache,
+func New(settings Settings) (middleware *Middleware, err error) {
+	err = settings.Validate()
+	if err != nil {
+		return nil, fmt.Errorf("settings validation: %w", err)
 	}
+
+	return &Middleware{
+		cache: settings.Cache,
+	}, nil
 }
 
 func (m *Middleware) Wrap(next dns.Handler) dns.Handler { //nolint:ireturn
diff --git a/pkg/middlewares/cache/settings.go b/pkg/middlewares/cache/settings.go
new file mode 100644
index 00000000..147b3b25
--- /dev/null
+++ b/pkg/middlewares/cache/settings.go
@@ -0,0 +1,22 @@
+package cache
+
+import (
+	"errors"
+	"fmt"
+)
+
+type Settings struct {
+	Cache Cache
+}
+
+var (
+	ErrCacheMustBeSet = errors.New("cache must be set")
+)
+
+func (s *Settings) Validate() (err error) {
+	if s.Cache == nil {
+		return fmt.Errorf("%w", ErrCacheMustBeSet)
+	}
+
+	return nil
+}
diff --git a/pkg/middlewares/filter/middleware.go b/pkg/middlewares/filter/middleware.go
index 5c394c65..37167116 100644
--- a/pkg/middlewares/filter/middleware.go
+++ b/pkg/middlewares/filter/middleware.go
@@ -1,6 +1,8 @@
 package filter
 
 import (
+	"fmt"
+
 	"github.com/miekg/dns"
 	"github.com/qdm12/dns/v2/internal/stateful"
 )
@@ -9,10 +11,15 @@ type Middleware struct {
 	filter Filter
 }
 
-func New(filter Filter) *Middleware {
-	return &Middleware{
-		filter: filter,
+func New(settings Settings) (middleware *Middleware, err error) {
+	err = settings.Validate()
+	if err != nil {
+		return nil, fmt.Errorf("settings validation: %w", err)
 	}
+
+	return &Middleware{
+		filter: settings.Filter,
+	}, nil
 }
 
 func (m *Middleware) Wrap(next dns.Handler) dns.Handler { //nolint:ireturn
diff --git a/pkg/middlewares/filter/settings.go b/pkg/middlewares/filter/settings.go
new file mode 100644
index 00000000..d6139e2c
--- /dev/null
+++ b/pkg/middlewares/filter/settings.go
@@ -0,0 +1,22 @@
+package filter
+
+import (
+	"errors"
+	"fmt"
+)
+
+type Settings struct {
+	Filter Filter
+}
+
+var (
+	ErrFilterMustBeSet = errors.New("filter must be set")
+)
+
+func (s *Settings) Validate() (err error) {
+	if s.Filter == nil {
+		return fmt.Errorf("%w", ErrFilterMustBeSet)
+	}
+
+	return nil
+}