feat: refactor resolver in separate package

cmd/doggo/api/api.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/go-chi/chi"
+	"github.com/go-chi/chi/middleware"
+	"github.com/knadh/koanf"
+	"github.com/mr-karan/doggo/pkg/utils"
+)
+
+var (
+	logger = utils.InitLogger()
+	k      = koanf.New(".")
+)
+
+type resp struct {
+	Status  string      `json:"status"`
+	Message string      `json:"message,omitempty"`
+	Data    interface{} `json:"data,omitempty"`
+}
+
+func main() {
+
+	r := chi.NewRouter()
+
+	// Setup middlewares.
+	r.Use(middleware.RequestID)
+	r.Use(middleware.RealIP)
+	r.Use(middleware.Logger)
+	r.Use(middleware.Recoverer)
+
+	r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+		sendSuccessResponse("Welcome to Doggo DNS!", w)
+		return
+	})
+
+	r.Get("/ping/", func(w http.ResponseWriter, r *http.Request) {
+		sendSuccessResponse("PONG", w)
+		return
+	})
+
+	r.Post("/lookup/", func(w http.ResponseWriter, r *http.Request) {
+		return
+	})
+
+	http.ListenAndServe(":3000", r)
+}
+
+// sendResponse sends an HTTP success response.
+func sendResponse(data interface{}, statusText string, status int, w http.ResponseWriter) {
+	w.WriteHeader(status)
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+
+	out, err := json.Marshal(resp{Status: statusText, Data: data})
+	if err != nil {
+		sendErrorResponse("Internal Server Error", http.StatusInternalServerError, nil, w)
+		return
+	}
+
+	_, _ = w.Write(out)
+}
+
+// sendSuccessResponse sends an HTTP success (200 OK) response.
+func sendSuccessResponse(data interface{}, w http.ResponseWriter) {
+	sendResponse(data, "success", http.StatusOK, w)
+}
+
+// sendErrorResponse sends an HTTP error response.
+func sendErrorResponse(message string, status int, data interface{}, w http.ResponseWriter) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(status)
+
+	resp := resp{Status: "error",
+		Message: message,
+		Data:    data}
+
+	out, _ := json.Marshal(resp)
+
+	_, _ = w.Write(out)
+}

cmd/doggo/cli/cli.go

@@ -3,11 +3,13 @@ package main
 import (
 	"os"
 	"strings"
+	"time"
 
 	"github.com/knadh/koanf"
 	"github.com/knadh/koanf/providers/posflag"
 	"github.com/miekg/dns"
 	"github.com/mr-karan/doggo/pkg/resolvers"
+	"github.com/mr-karan/doggo/pkg/utils"
 	"github.com/sirupsen/logrus"
 	flag "github.com/spf13/pflag"
 )
@@ -20,7 +22,7 @@ var (
 
 func main() {
 	var (
-		logger = initLogger()
+		logger = utils.InitLogger()
 		k      = koanf.New(".")
 	)
 
@@ -110,15 +112,21 @@ func main() {
 		hub.Logger.Exit(2)
 	}
 
-	// Load Resolver Options.
-	hub.loadResolverOptions()
-
 	// Load Resolvers.
-	err = hub.loadResolvers()
+	rslvrs, err := resolvers.LoadResolvers(resolvers.Options{
+		Nameservers: hub.Nameservers,
+		UseIPv4:     hub.QueryFlags.UseIPv4,
+		UseIPv6:     hub.QueryFlags.UseIPv6,
+		SearchList:  hub.ResolverOpts.SearchList,
+		Ndots:       hub.ResolverOpts.Ndots,
+		Timeout:     hub.QueryFlags.Timeout * time.Second,
+		Logger:      hub.Logger,
+	})
 	if err != nil {
 		hub.Logger.WithError(err).Error("error loading resolver")
 		hub.Logger.Exit(2)
 	}
+	hub.Resolvers = rslvrs
 
 	// Run the app.
 	hub.Logger.Debug("Starting doggo 🐶")
@@ -130,7 +138,7 @@ func main() {
 	// Resolve Queries.
 	var responses []resolvers.Response
 	for _, q := range hub.Questions {
-		for _, rslv := range hub.Resolver {
+		for _, rslv := range hub.Resolvers {
 			resp, err := rslv.Lookup(q)
 			if err != nil {
 				hub.Logger.WithError(err).Error("error looking up DNS records")

cmd/doggo/cli/hub.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"github.com/miekg/dns"
+	"github.com/mr-karan/doggo/pkg/models"
+	"github.com/mr-karan/doggo/pkg/resolvers"
+	"github.com/sirupsen/logrus"
+)
+
+// Hub represents the structure for all app wide configuration.
+type Hub struct {
+	Logger       *logrus.Logger
+	Version      string
+	QueryFlags   models.QueryFlags
+	UnparsedArgs []string
+	Questions    []dns.Question
+	Resolvers    []resolvers.Resolver
+	ResolverOpts resolvers.Options
+	Nameservers  []models.Nameserver
+}
+
+// NewHub initializes an instance of Hub which holds app wide configuration.
+func NewHub(logger *logrus.Logger, buildVersion string) *Hub {
+	hub := &Hub{
+		Logger:  logger,
+		Version: buildVersion,
+		QueryFlags: models.QueryFlags{
+			QNames:      []string{},
+			QTypes:      []string{},
+			QClasses:    []string{},
+			Nameservers: []string{},
+		},
+		Nameservers: []models.Nameserver{},
+	}
+	return hub
+}

cmd/doggo/cli/nameservers.go

@@ -6,19 +6,7 @@ import (
 	"net/url"
 
 	"github.com/mr-karan/doggo/pkg/config"
-)
-
-const (
-	// DefaultTLSPort specifies the default port for a DNS server connecting over TCP over TLS
-	DefaultTLSPort = "853"
-	// DefaultUDPPort specifies the default port for a DNS server connecting over UDP
-	DefaultUDPPort = "53"
-	// DefaultTCPPort specifies the default port for a DNS server connecting over TCP
-	DefaultTCPPort = "53"
-	UDPResolver    = "udp"
-	DOHResolver    = "doh"
-	TCPResolver    = "tcp"
-	DOTResolver    = "dot"
+	"github.com/mr-karan/doggo/pkg/models"
 )
 
 // loadNameservers reads all the user given
@@ -62,56 +50,56 @@ func (hub *Hub) loadNameservers() error {
 	return nil
 }
 
-func getDefaultServers() ([]Nameserver, int, []string, error) {
+func getDefaultServers() ([]models.Nameserver, int, []string, error) {
 	dnsServers, ndots, search, err := config.GetDefaultServers()
 	if err != nil {
 		return nil, 0, nil, err
 	}
-	servers := make([]Nameserver, 0, len(dnsServers))
+	servers := make([]models.Nameserver, 0, len(dnsServers))
 	for _, s := range dnsServers {
-		ns := Nameserver{
-			Type:    UDPResolver,
-			Address: net.JoinHostPort(s, DefaultUDPPort),
+		ns := models.Nameserver{
+			Type:    models.UDPResolver,
+			Address: net.JoinHostPort(s, models.DefaultUDPPort),
 		}
 		servers = append(servers, ns)
 	}
 	return servers, ndots, search, nil
 }
 
-func initNameserver(n string) (Nameserver, error) {
+func initNameserver(n string) (models.Nameserver, error) {
 	// Instantiate a UDP resolver with default port as a fallback.
-	ns := Nameserver{
-		Type:    UDPResolver,
-		Address: net.JoinHostPort(n, DefaultUDPPort),
+	ns := models.Nameserver{
+		Type:    models.UDPResolver,
+		Address: net.JoinHostPort(n, models.DefaultUDPPort),
 	}
 	u, err := url.Parse(n)
 	if err != nil {
 		return ns, err
 	}
 	if u.Scheme == "https" {
-		ns.Type = DOHResolver
+		ns.Type = models.DOHResolver
 		ns.Address = u.String()
 	}
 	if u.Scheme == "tls" {
-		ns.Type = DOTResolver
+		ns.Type = models.DOTResolver
 		if u.Port() == "" {
-			ns.Address = net.JoinHostPort(u.Hostname(), DefaultTLSPort)
+			ns.Address = net.JoinHostPort(u.Hostname(), models.DefaultTLSPort)
 		} else {
 			ns.Address = net.JoinHostPort(u.Hostname(), u.Port())
 		}
 	}
 	if u.Scheme == "tcp" {
-		ns.Type = TCPResolver
+		ns.Type = models.TCPResolver
 		if u.Port() == "" {
-			ns.Address = net.JoinHostPort(u.Hostname(), DefaultTCPPort)
+			ns.Address = net.JoinHostPort(u.Hostname(), models.DefaultTCPPort)
 		} else {
 			ns.Address = net.JoinHostPort(u.Hostname(), u.Port())
 		}
 	}
 	if u.Scheme == "udp" {
-		ns.Type = UDPResolver
+		ns.Type = models.UDPResolver
 		if u.Port() == "" {
-			ns.Address = net.JoinHostPort(u.Hostname(), DefaultUDPPort)
+			ns.Address = net.JoinHostPort(u.Hostname(), models.DefaultUDPPort)
 		} else {
 			ns.Address = net.JoinHostPort(u.Hostname(), u.Port())
 		}

cmd/doggo/cli/resolver.go

@@ -0,0 +1 @@
+package main

cmd/doggo/hub.go

@@ -1,71 +0,0 @@
-package main
-
-import (
-	"time"
-
-	"github.com/miekg/dns"
-	"github.com/mr-karan/doggo/pkg/resolvers"
-	"github.com/sirupsen/logrus"
-)
-
-// Hub represents the structure for all app wide configuration.
-type Hub struct {
-	Logger       *logrus.Logger
-	Version      string
-	QueryFlags   QueryFlags
-	UnparsedArgs []string
-	Questions    []dns.Question
-	Resolver     []resolvers.Resolver
-	ResolverOpts resolvers.Options
-	Nameservers  []Nameserver
-}
-
-// QueryFlags is used store the query params
-// supplied by the user.
-type QueryFlags struct {
-	QNames           []string      `koanf:"query"`
-	QTypes           []string      `koanf:"type"`
-	QClasses         []string      `koanf:"class"`
-	Nameservers      []string      `koanf:"nameserver"`
-	UseIPv4          bool          `koanf:"ipv4"`
-	UseIPv6          bool          `koanf:"ipv6"`
-	DisplayTimeTaken bool          `koanf:"time"`
-	ShowJSON         bool          `koanf:"json"`
-	UseSearchList    bool          `koanf:"search"`
-	Ndots            int           `koanf:"ndots"`
-	Color            bool          `koanf:"color"`
-	Timeout          time.Duration `koanf:"timeout"`
-}
-
-// Nameserver represents the type of Nameserver
-// along with the server address.
-type Nameserver struct {
-	Address string
-	Type    string
-}
-
-// NewHub initializes an instance of Hub which holds app wide configuration.
-func NewHub(logger *logrus.Logger, buildVersion string) *Hub {
-	hub := &Hub{
-		Logger:  logger,
-		Version: buildVersion,
-		QueryFlags: QueryFlags{
-			QNames:      []string{},
-			QTypes:      []string{},
-			QClasses:    []string{},
-			Nameservers: []string{},
-		},
-		Nameservers: []Nameserver{},
-	}
-	return hub
-}
-
-// initLogger initializes logger
-func initLogger() *logrus.Logger {
-	logger := logrus.New()
-	logger.SetFormatter(&logrus.TextFormatter{
-		FullTimestamp:          true,
-		DisableLevelTruncation: true,
-	})
-	return logger
-}

cmd/doggo/resolver.go

@@ -1,79 +0,0 @@
-package main
-
-import (
-	"time"
-
-	"github.com/mr-karan/doggo/pkg/resolvers"
-)
-
-// loadResolverOptions loads the common options
-// to configure a resolver from the query args.
-func (hub *Hub) loadResolverOptions() {
-	hub.ResolverOpts.Timeout = hub.QueryFlags.Timeout
-}
-
-// loadResolvers loads differently configured
-// resolvers based on a list of nameserver.
-func (hub *Hub) loadResolvers() error {
-	var resolverOpts = resolvers.Options{
-		Timeout:    hub.QueryFlags.Timeout * time.Second,
-		Ndots:      hub.ResolverOpts.Ndots,
-		SearchList: hub.ResolverOpts.SearchList,
-		Logger:     hub.Logger,
-	}
-	// for each nameserver, initialise the correct resolver
-	for _, ns := range hub.Nameservers {
-		if ns.Type == DOHResolver {
-			hub.Logger.Debug("initiating DOH resolver")
-			rslvr, err := resolvers.NewDOHResolver(ns.Address, resolverOpts)
-			if err != nil {
-				return err
-			}
-			hub.Resolver = append(hub.Resolver, rslvr)
-		}
-		if ns.Type == DOTResolver {
-			hub.Logger.Debug("initiating DOT resolver")
-			rslvr, err := resolvers.NewClassicResolver(ns.Address,
-				resolvers.ClassicResolverOpts{
-					IPv4Only: hub.QueryFlags.UseIPv4,
-					IPv6Only: hub.QueryFlags.UseIPv6,
-					UseTLS:   true,
-					UseTCP:   true,
-				}, resolverOpts)
-
-			if err != nil {
-				return err
-			}
-			hub.Resolver = append(hub.Resolver, rslvr)
-		}
-		if ns.Type == TCPResolver {
-			hub.Logger.Debug("initiating TCP resolver")
-			rslvr, err := resolvers.NewClassicResolver(ns.Address,
-				resolvers.ClassicResolverOpts{
-					IPv4Only: hub.QueryFlags.UseIPv4,
-					IPv6Only: hub.QueryFlags.UseIPv6,
-					UseTLS:   false,
-					UseTCP:   true,
-				}, resolverOpts)
-			if err != nil {
-				return err
-			}
-			hub.Resolver = append(hub.Resolver, rslvr)
-		}
-		if ns.Type == UDPResolver {
-			hub.Logger.Debug("initiating UDP resolver")
-			rslvr, err := resolvers.NewClassicResolver(ns.Address,
-				resolvers.ClassicResolverOpts{
-					IPv4Only: hub.QueryFlags.UseIPv4,
-					IPv6Only: hub.QueryFlags.UseIPv6,
-					UseTLS:   false,
-					UseTCP:   false,
-				}, resolverOpts)
-			if err != nil {
-				return err
-			}
-			hub.Resolver = append(hub.Resolver, rslvr)
-		}
-	}
-	return nil
-}