chore(pkg/middlewares): use settings for cache and filter constructors (future proofing for compatibility)

Author: qdm12

examples/doh-server/main.go

@@ -22,7 +22,11 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	cacheMiddleware := cachemiddleware.New(cache)
+
+	cacheMiddleware, err := cachemiddleware.New(cachemiddleware.Settings{Cache: cache})
+	if err != nil {
+		log.Fatal(err)
+	}
 
 	server, err := doh.NewServer(doh.ServerSettings{
 		Middlewares: []doh.Middleware{cacheMiddleware},

examples/dot-server/main.go

@@ -22,7 +22,11 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	cacheMiddleware := cachemiddleware.New(cache)
+
+	cacheMiddleware, err := cachemiddleware.New(cachemiddleware.Settings{Cache: cache})
+	if err != nil {
+		log.Fatal(err)
+	}
 
 	server, err := dot.NewServer(dot.ServerSettings{
 		Middlewares: []dot.Middleware{cacheMiddleware},

internal/setup/dns.go

@@ -20,10 +20,19 @@ func DNS(userSettings settings.Settings, //nolint:ireturn
 	server Service, err error) {
 	var middlewares []Middleware
 
-	middlewares = append(middlewares, cachemiddleware.New(cache))
+	cacheMiddleware, err := cachemiddleware.New(cachemiddleware.Settings{Cache: cache})
+	if err != nil {
+		return nil, fmt.Errorf("creating cache middleware: %w", err)
+	}
+	middlewares = append(middlewares, cacheMiddleware)
+
+	filterMiddleware, err := filtermiddleware.New(filtermiddleware.Settings{Filter: filter})
+	if err != nil {
+		return nil, fmt.Errorf("creating filter middleware: %w", err)
+	}
 	// Note the filter middleware must be wrapping the cache middleware
 	// to catch filtered responses found from the cache.
-	middlewares = append(middlewares, filtermiddleware.New(filter))
+	middlewares = append(middlewares, filterMiddleware)
 
 	commonPrometheus := prometheus.Settings{
 		Prefix:   *userSettings.Metrics.Prometheus.Subsystem,

pkg/doh/integration_test.go

@@ -219,7 +219,8 @@ func Test_Server_Mocks(t *testing.T) {
 	cache.EXPECT().Add(
 		mockhelp.NewMatcherRequest(expectedRequestAAAA),
 		mockhelp.NewMatcherResponse(expectedResponseAAAA))
-	cacheMiddleware := cachemiddleware.New(cache)
+	cacheMiddleware, err := cachemiddleware.New(cachemiddleware.Settings{Cache: cache})
+	require.NoError(t, err)
 
 	filter := NewMockfilter(ctrl)
 	filter.EXPECT().
@@ -234,7 +235,8 @@ func Test_Server_Mocks(t *testing.T) {
 	filter.EXPECT().
 		FilterResponse(mockhelp.NewMatcherResponse(expectedResponseAAAA)).
 		Return(false)
-	filterMiddleware := filtermiddleware.New(filter)
+	filterMiddleware, err := filtermiddleware.New(filtermiddleware.Settings{Filter: filter})
+	require.NoError(t, err)
 
 	logger := NewMockLogger(ctrl)
 	logger.EXPECT().Info(mockhelp.NewMatcherRegex("DNS server listening on .*:[1-9][0-9]{0,4}"))

pkg/dot/integration_test.go

@@ -215,7 +215,8 @@ func Test_Server_Mocks(t *testing.T) {
 	cache.EXPECT().Add(
 		mockhelp.NewMatcherRequest(expectedRequestAAAA),
 		mockhelp.NewMatcherResponse(expectedResponseAAAA))
-	cacheMiddleware := cachemiddleware.New(cache)
+	cacheMiddleware, err := cachemiddleware.New(cachemiddleware.Settings{Cache: cache})
+	require.NoError(t, err)
 
 	filter := NewMockfilter(ctrl)
 	filter.EXPECT().
@@ -230,7 +231,8 @@ func Test_Server_Mocks(t *testing.T) {
 	filter.EXPECT().
 		FilterResponse(mockhelp.NewMatcherResponse(expectedResponseAAAA)).
 		Return(false)
-	filterMiddleware := filtermiddleware.New(filter)
+	filterMiddleware, err := filtermiddleware.New(filtermiddleware.Settings{Filter: filter})
+	require.NoError(t, err)
 
 	logger := NewMockLogger(ctrl)
 	logger.EXPECT().Info(mockhelp.NewMatcherRegex("DNS server listening on .*:[1-9][0-9]{0,4}"))

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

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
+}

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

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
+}