refactor: run PTR queries before output printer

main.go

@@ -458,13 +458,22 @@ All long form (--) flags can be toggled with the dig-standard +[no]flag notation
 			}
 		}
 
-		entries = append(entries, &output.Entry{
+		e := &output.Entry{
 			Queries: msgs,
 			Replies: replies,
 			Server:  server,
-			Txp:     txp,
 			Time:    time.Since(startTime),
-		})
+		}
+
+		if opts.ResolveIPs {
+			e.LoadPTRs(txp)
+		}
+
+		entries = append(entries, e)
+
+		if err := (*txp).Close(); err != nil {
+			return fmt.Errorf("closing transport: %s", err)
+		}
 	}
 
 	printer := output.Printer{

output/output.go

@@ -4,11 +4,12 @@ import (
 	"io"
 	"time"
 
+	"github.com/natesales/q/transport"
+
 	"github.com/miekg/dns"
 	log "github.com/sirupsen/logrus"
 
 	"github.com/natesales/q/cli"
-	"github.com/natesales/q/transport"
 )
 
 // Printer stores global options across multiple entries
@@ -30,15 +31,12 @@ type Entry struct {
 	// Time is the total time it took to query this server
 	Time time.Duration
 
-	// Txp is the transport used to resolve IP addresses in A/AAAA records to their PTR records
-	Txp *transport.Transport `json:"-"`
-
 	PTRs        map[string]string `json:"-"` // IP -> PTR value
 	existingRRs map[string]bool
 }
 
 // LoadPTRs populates an entry's PTRs map with PTR values for all A/AAAA records
-func (e *Entry) LoadPTRs() {
+func (e *Entry) LoadPTRs(txp *transport.Transport) {
 	// Initialize PTR cache if it doesn't exist
 	if e.PTRs == nil {
 		e.PTRs = make(map[string]string)
@@ -66,7 +64,7 @@ func (e *Entry) LoadPTRs() {
 			msg.SetQuestion(qname, dns.TypePTR)
 
 			// Resolve qname and cache result
-			resp, err := (*e.Txp).Exchange(&msg)
+			resp, err := (*txp).Exchange(&msg)
 			if err != nil {
 				log.Debugf("error resolving PTR record: %s", err)
 			}

output/output_test.go

@@ -38,7 +38,6 @@ var entries = []*Entry{
 		Replies:     replies(),
 		Server:      "192.0.2.10",
 		Time:        time.Second * 2,
-		Txp:         nil,
 		PTRs:        nil,
 		existingRRs: nil,
 	},

output/pretty.go

@@ -47,42 +47,6 @@ func (p Printer) PrettyPrintNSID(entries []*Entry) {
 	}
 }
 
-// ptr resolves an IP address (not an arpa FQDN) to its PTR record
-func (e *Entry) ptr(ip string) (string, error) {
-	// Initialize ptrCache if it doesn't exist
-	if e.PTRs == nil {
-		e.PTRs = make(map[string]string)
-	}
-
-	// Return the result from cache if we already have it
-	if ptr, ok := e.PTRs[ip]; ok {
-		return ptr, nil
-	}
-
-	// Create PTR query
-	qname, err := dns.ReverseAddr(ip)
-	if err != nil {
-		log.Fatalf("error reversing PTR record: %s", err)
-	}
-	msg := dns.Msg{}
-	msg.SetQuestion(qname, dns.TypePTR)
-
-	// Resolve qname and cache result
-	resp, err := (*e.Txp).Exchange(&msg)
-	if err != nil {
-		return "", err
-	}
-
-	// Cache and return
-	if len(resp.Answer) > 0 {
-		e.PTRs[ip] = resp.Answer[0].(*dns.PTR).Ptr
-		return e.PTRs[ip], nil
-	}
-
-	// No value
-	return "", fmt.Errorf("no PTR record found for %s", ip)
-}
-
 // parseRR converts an RR into a pretty string and returns the qname, ttl, type, value, and whether to skip printing it because it's a duplicate
 func (e *Entry) parseRR(a dns.RR, opts *cli.Flags) *RR {
 	// Initialize existingRRs map if it doesn't exist
@@ -128,11 +92,7 @@ func (e *Entry) parseRR(a dns.RR, opts *cli.Flags) *RR {
 
 	// Handle PTR resolution
 	if opts.ResolveIPs && (a.Header().Rrtype == dns.TypeA || a.Header().Rrtype == dns.TypeAAAA) {
-		if ptr, err := e.ptr(valCopy); err == nil {
-			val += util.Color(util.ColorMagenta, fmt.Sprintf(" (%s)", ptr))
-		} else {
-			log.Warnf("PTR resolution: %s", err)
-		}
+		val += util.Color(util.ColorMagenta, fmt.Sprintf(" (%s)", e.PTRs[valCopy]))
 	}
 
 	// Server suffix

output/pretty_test.go

@@ -10,16 +10,6 @@ import (
 	"github.com/natesales/q/util"
 )
 
-func TestOutputPrettyPTRCache(t *testing.T) {
-	var e Entry
-	e.PTRs = make(map[string]string)
-	e.PTRs["192.0.2.1"] = "example.com."
-
-	ptr, err := e.ptr("192.0.2.1")
-	assert.Nil(t, err)
-	assert.Equal(t, "example.com.", ptr)
-}
-
 func TestOutputPrettyPrintColumn(t *testing.T) {
 	var buf bytes.Buffer
 	util.UseColor = false