feat: working finally

TODO.md

@@ -1,10 +1,11 @@
 # doggo - v1.0 Milestone
 
 ## Resolver
-- [ ] Create a DNS Resolver struct
+- [x] Create a DNS Resolver struct
 - [ ] Add methods to initialise the config, set defaults
-- [ ] Add a resolve method
-- [ ] Make it separate from Hub
+- [x] Add a resolve method
+- [x] Make it separate from Hub
+- [ ] Parse output into separate fields
 
 ## CLI Features
 - [ ] `digfile`
@@ -15,10 +16,10 @@
 - [ ] Table output
 
 ## CLI Grunt
-- [ ] Query args
-- [ ] Neatly package them to load args in different functions
-- [ ] Upper case is not mandatory for query type/classes
-
+- [x] Query args
+- [x] Neatly package them to load args in different functions
+- [x] Upper case is not mandatory for query type/classes
+- [ ] Output
 ## Tests
 
 ## Documentation

cmd/cli.go

@@ -2,9 +2,7 @@ package main
 
 import (
 	"os"
-	"strings"
 
-	resolver "github.com/mr-karan/doggo/pkg/resolve"
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 )
@@ -13,13 +11,15 @@ var (
 	// Version and date of the build. This is injected at build-time.
 	buildVersion   = "unknown"
 	buildDate      = "unknown"
+	verboseEnabled = false
 )
 
 // initLogger initializes logger
 func initLogger(verbose bool) *logrus.Logger {
 	logger := logrus.New()
 	logger.SetFormatter(&logrus.TextFormatter{
-		FullTimestamp: true,
+		DisableTimestamp:       true,
+		DisableLevelTruncation: true,
 	})
 	// Set logger level
 	if verbose {
@@ -32,66 +32,61 @@ func initLogger(verbose bool) *logrus.Logger {
 }
 
 func main() {
-	// Intialize new CLI app
-	app := cli.NewApp()
-	app.Name = "doggo"
-	app.Usage = "Command-line DNS Client"
-	app.Version = buildVersion
 	var (
-		logger = initLogger(true)
+		logger = initLogger(verboseEnabled)
+		app    = cli.NewApp()
 	)
 	// Initialize hub.
 	hub := NewHub(logger, buildVersion)
-	// Register command line args.
+
+	// Configure CLI app.
+	app.Name = "doggo"
+	app.Usage = "Command-line DNS Client"
+	app.Version = buildVersion
+
+	var qFlags QueryFlags
+	// Register command line flags.
 	app.Flags = []cli.Flag{
 		&cli.StringSliceFlag{
 			Name:        "query",
 			Usage:       "Domain name to query",
-			Destination: hub.Domains,
+			Destination: qFlags.QNames,
+		},
+		&cli.StringSliceFlag{
+			Name:        "type",
+			Usage:       "Type of DNS record to be queried (A, AAAA, MX etc)",
+			Destination: qFlags.QTypes,
+		},
+		&cli.StringSliceFlag{
+			Name:        "nameserver",
+			Usage:       "Address of the nameserver to send packets to",
+			Destination: qFlags.Nameservers,
+		},
+		&cli.StringSliceFlag{
+			Name:        "class",
+			Usage:       "Network class of the DNS record to be queried (IN, CH, HS etc)",
+			Destination: qFlags.QClasses,
 		},
 		&cli.BoolFlag{
 			Name:        "verbose",
 			Usage:       "Enable verbose logging",
+			Destination: &verboseEnabled,
+			DefaultText: "false",
 		},
 	}
-	app.Action = func(c *cli.Context) error {
 
-		// parse arguments
-		var domains cli.StringSlice
-		for _, arg := range c.Args().Slice() {
-			if strings.HasPrefix(arg, "@") {
-				hub.Nameservers = append(hub.Nameservers, arg)
-			} else if isUpper(arg) {
-				if parseQueryType(arg) {
-					hub.QTypes = append(hub.QTypes, arg)
-				} else if parseQueryClass(arg) {
-					hub.QClass = append(hub.QClass, arg)
+	app.Before = hub.loadQueryArgs
+	app.Action = func(c *cli.Context) error {
+		if len(hub.QueryFlags.QNames.Value()) == 0 {
+			cli.ShowAppHelpAndExit(c, 0)
 		}
-			} else {
-				domains.Set(arg)
-				hub.Domains = &domains
-			}
-		}
-		// load defaults
-		if len(hub.QTypes) == 0 {
-			hub.QTypes = append(hub.QTypes, "A")
-		}
-		if len(hub.Nameservers) == 0 {
-			ns, err := resolver.GetDefaultNameserver()
-			if err != nil {
-				panic(err)
-			}
-			hub.Nameservers = append(hub.Nameservers, ns)
-		}
-		// resolve query
-		hub.Resolve()
+		hub.Lookup(c)
 		return nil
 	}
-
 	// Run the app.
-	hub.Logger.Info("Starting doggo...")
+	hub.Logger.Debug("Starting doggo...")
 	err := app.Run(os.Args)
 	if err != nil {
-		logger.Errorf("Something terrbily went wrong: %s", err)
+		logger.Errorf("oops! we encountered an issue: %s", err)
 	}
 }

cmd/hub.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"github.com/miekg/dns"
+	"github.com/mr-karan/doggo/pkg/resolve"
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 )
@@ -9,25 +11,31 @@ import (
 type Hub struct {
 	Logger     *logrus.Logger
 	Version    string
-	Domains     *cli.StringSlice
-	QTypes      []string
-	QClass      []string
-	Nameservers []string
+	QueryFlags QueryFlags
+	Questions  []dns.Question
+	Resolver   *resolve.Resolver
+}
+
+// QueryFlags is used store the value of CLI flags.
+type QueryFlags struct {
+	QNames      *cli.StringSlice
+	QTypes      *cli.StringSlice
+	QClasses    *cli.StringSlice
+	Nameservers *cli.StringSlice
 }
 
 // NewHub initializes an instance of Hub which holds app wide configuration.
 func NewHub(logger *logrus.Logger, buildVersion string) *Hub {
+	// Initialise Resolver
 	hub := &Hub{
 		Logger:  logger,
 		Version: buildVersion,
+		QueryFlags: QueryFlags{
+			QNames:      cli.NewStringSlice(),
+			QTypes:      cli.NewStringSlice(),
+			QClasses:    cli.NewStringSlice(),
+			Nameservers: cli.NewStringSlice(),
+		},
 	}
 	return hub
 }
-
-// initApp acts like a middleware to load app managers with Hub before running any command.
-// Use this middleware to perform any action before the command is run.
-func (hub *Hub) initApp(fn cli.ActionFunc) cli.ActionFunc {
-	return func(c *cli.Context) error {
-		return fn(c)
-	}
-}

cmd/lookup.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"strings"
+
+	"github.com/miekg/dns"
+	"github.com/urfave/cli/v2"
+)
+
+func (hub *Hub) Lookup(c *cli.Context) error {
+	hub.prepareQuestions()
+	err := hub.Resolver.Lookup(hub.Questions)
+	if err != nil {
+		hub.Logger.Error(err)
+	}
+	return nil
+}
+
+// prepareQuestions iterates on list of domain names
+// and prepare a list of questions
+// sent to the server with all possible combinations.
+func (hub *Hub) prepareQuestions() {
+	var question dns.Question
+	for _, name := range hub.QueryFlags.QNames.Value() {
+		question.Name = dns.Fqdn(name)
+		// iterate on a list of query types.
+		for _, q := range hub.QueryFlags.QTypes.Value() {
+			question.Qtype = dns.StringToType[strings.ToUpper(q)]
+			// iterate on a list of query classes.
+			for _, c := range hub.QueryFlags.QClasses.Value() {
+				question.Qclass = dns.StringToClass[strings.ToUpper(c)]
+				// append a new question for each possible pair.
+				hub.Questions = append(hub.Questions, question)
+			}
+		}
+	}
+}

cmd/parse.go

@@ -1,13 +1,76 @@
 package main
 
-func (hub *Hub) loadFlags() {
+import (
+	"runtime"
+	"strings"
 
+	"github.com/miekg/dns"
+	"github.com/mr-karan/doggo/pkg/resolve"
+	"github.com/urfave/cli/v2"
+)
+
+func (hub *Hub) loadQueryArgs(c *cli.Context) error {
+	err := hub.parseFreeArgs(c)
+	if err != nil {
+		cli.Exit("Error parsing arguments", -1)
+	}
+	err = hub.loadResolver(c)
+	if err != nil {
+		cli.Exit("Error parsing nameservers", -1)
+	}
+	hub.loadFallbacks(c)
+	return err
 }
 
-func (hub *Hub) loadFreeForm() {
-
+// parseFreeArgs tries to parse all the arguments
+// given to the CLI. These arguments don't have any specific
+// order so we have to deduce based on the pattern of argument.
+// For eg, a nameserver must always begin with `@`. In this
+// pattern we deduce the arguments and map it to internal query
+// options. In case an argument isn't able to fit in any of the existing
+// pattern it is considered to be a "query name".
+func (hub *Hub) parseFreeArgs(c *cli.Context) error {
+	for _, arg := range c.Args().Slice() {
+		if strings.HasPrefix(arg, "@") {
+			hub.QueryFlags.Nameservers.Set(arg)
+		} else if _, ok := dns.StringToType[strings.ToUpper(arg)]; ok {
+			hub.QueryFlags.QTypes.Set(arg)
+		} else if _, ok := dns.StringToClass[strings.ToUpper(arg)]; ok {
+			hub.QueryFlags.QClasses.Set(arg)
+		} else {
+			// if nothing matches, consider it's a query name.
+			hub.QueryFlags.QNames.Set(arg)
+		}
+	}
+	return nil
 }
 
-func (hub *Hub) loadFallbacks() {
-
+// loadFallbacks sets fallbacks for options
+// that are not specified by the user.
+func (hub *Hub) loadFallbacks(c *cli.Context) {
+	if len(hub.QueryFlags.QTypes.Value()) == 0 {
+		hub.QueryFlags.QTypes.Set("A")
+	}
+	if len(hub.QueryFlags.QClasses.Value()) == 0 {
+		hub.QueryFlags.QClasses.Set("IN")
+	}
+}
+
+// loadResolver checks
+func (hub *Hub) loadResolver(c *cli.Context) error {
+	if len(hub.QueryFlags.Nameservers.Value()) == 0 {
+		if runtime.GOOS == "windows" {
+			// TODO: Add a method for reading system default nameserver in windows.
+		} else {
+			rslvr, err := resolve.NewResolverFromResolvFile(resolve.DefaultResolvConfPath)
+			if err != nil {
+				return err
+			}
+			hub.Resolver = rslvr
+		}
+	} else {
+		rslvr := resolve.NewResolver(hub.QueryFlags.Nameservers.Value())
+		hub.Resolver = rslvr
+	}
+	return nil
 }

cmd/resolve.go

@@ -1,32 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	"github.com/miekg/dns"
-)
-
-// Resolve resolves the domain name
-func (hub *Hub) Resolve() {
-	var messages = make([]dns.Msg, 0, len(hub.Domains.Value()))
-	for _, d := range hub.Domains.Value() {
-		msg := dns.Msg{}
-		msg.Id = dns.Id()
-		msg.RecursionDesired = true
-		msg.Question = []dns.Question{(dns.Question{dns.Fqdn(d), dns.TypeA, dns.ClassINET})}
-		messages = append(messages, msg)
-	}
-	c := new(dns.Client)
-	for _, msg := range messages {
-		in, rtt, err := c.Exchange(&msg, "127.0.0.1:53")
-		if err != nil {
-			panic(err)
-		}
-		for _, ans := range in.Answer {
-			if t, ok := ans.(*dns.A); ok {
-				fmt.Println(t.String())
-			}
-		}
-		fmt.Println("rtt is", rtt, msg.Question[0].Name)
-	}
-}

cmd/utils.go

@@ -1,35 +0,0 @@
-package main
-
-import "unicode"
-
-var (
-	QTYPES = []string{"A", "AAAA", "MX"}
-	QCLASS = []string{"CN", "AAAA", "MX"}
-)
-
-func isUpper(s string) bool {
-	for _, r := range s {
-		if !unicode.IsUpper(r) && unicode.IsLetter(r) {
-			return false
-		}
-	}
-	return true
-}
-
-func parseQueryType(s string) bool {
-	for _, b := range QTYPES {
-		if b == s {
-			return true
-		}
-	}
-	return false
-}
-
-func parseQueryClass(s string) bool {
-	for _, b := range QCLASS {
-		if b == s {
-			return true
-		}
-	}
-	return false
-}

pkg/models/models.go

@@ -1,12 +0,0 @@
-package models
-
-// Question represents a given query to the client.
-// A question can have multiple domains, multiple nameservers
-// but it's the responsibility of the client to send each question
-// to the nameserver and collect responses.
-type Question struct {
-	Domain      []string
-	Nameservers []string
-	QClass      []uint16
-	QType       []uint16
-}

pkg/resolve/nameserver.go

@@ -1,33 +0,0 @@
-package resolve
-
-import (
-	"bufio"
-	"os"
-	"strings"
-)
-
-// GetDefaultNameserver reads `/etc/resolv.conf` to determine the default
-// nameserver configured. Returns an error if unable to parse or
-// no nameserver specified. It returns as soon as it finds a line
-// with `nameserver` prefix.
-// An example format:
-// `nameserver 127.0.0.1`
-
-func GetDefaultNameserver() (string, error) {
-	file, err := os.Open("/etc/resolv.conf")
-	if err != nil {
-		return "", err
-	}
-	defer file.Close()
-
-	scanner := bufio.NewScanner(file)
-	for scanner.Scan() {
-		if strings.HasPrefix(scanner.Text(), "nameserver") {
-			return strings.Fields(scanner.Text())[1], nil
-		}
-	}
-	if err := scanner.Err(); err != nil {
-		return "", err
-	}
-	return "", err
-}

pkg/resolve/resolver.go

@@ -54,30 +54,24 @@ func NewResolverFromResolvFile(resolvFilePath string) (*Resolver, error) {
 	}, nil
 }
 
-func (r *Resolver) Lookup(domains []string) []error {
-	// Prepare a list of DNS messages to be sent to the server.
+// Lookup prepare a list of DNS messages to be sent to the server.
 // It's possible to send multiple question in one message
 // but some nameservers are not able to
-	var messages = make([]dns.Msg, 0, len(domains))
-
-	for _, d := range domains {
+func (r *Resolver) Lookup(questions []dns.Question) error {
+	var messages = make([]dns.Msg, 0, len(questions))
+	for _, q := range questions {
 		msg := dns.Msg{}
 		msg.Id = dns.Id()
 		msg.RecursionDesired = true
 		// It's recommended to only send 1 question for 1 DNS message.
-		msg.Question = []dns.Question{(dns.Question{
-			Name:   dns.Fqdn(d),
-			Qtype:  dns.TypeA,
-			Qclass: dns.ClassINET,
-		})}
+		msg.Question = []dns.Question{q}
 		messages = append(messages, msg)
 	}
-	var errors []error
 	for _, msg := range messages {
 		for _, srv := range r.servers {
 			in, rtt, err := r.client.Exchange(&msg, srv)
 			if err != nil {
-				errors = append(errors, err)
+				return err
 			}
 			for _, ans := range in.Answer {
 				if t, ok := ans.(*dns.A); ok {
@@ -87,5 +81,5 @@ func (r *Resolver) Lookup(domains []string) []error {
 			fmt.Println("rtt is", rtt, msg.Question)
 		}
 	}
-	return errors
+	return nil
 }