lint warnings

36 files changed, 181 insertions, 147 deletions

diff --git a/cmd/dcat/main.go b/cmd/dcat/main.go
index 98da089..a50be51 100644
--- a/cmd/dcat/main.go
+++ b/cmd/dcat/main.go
@@ -59,8 +59,10 @@ func main() {
 	dlog.Start(ctx, &wg, source.Client)
 
 	if pprof != "" {
-		go http.ListenAndServe(pprof, nil)
-		dlog.Client.Info("Started PProf", pprof)
+		dlog.Client.Info("Starting PProf", pprof)
+		go func() {
+			panic(http.ListenAndServe(pprof, nil))
+		}()
 	}
 
 	client, err := clients.NewCatClient(args)
diff --git a/cmd/dgrep/main.go b/cmd/dgrep/main.go
index 7c3cc3e..19f818b 100644
--- a/cmd/dgrep/main.go
+++ b/cmd/dgrep/main.go
@@ -69,8 +69,10 @@ func main() {
 	}
 
 	if pprof != "" {
-		go http.ListenAndServe(pprof, nil)
-		dlog.Client.Info("Started PProf", pprof)
+		dlog.Client.Info("Starting PProf", pprof)
+		go func() {
+			panic(http.ListenAndServe(pprof, nil))
+		}()
 	}
 
 	client, err := clients.NewGrepClient(args)
diff --git a/cmd/dmap/main.go b/cmd/dmap/main.go
index e024b37..a8a52a2 100644
--- a/cmd/dmap/main.go
+++ b/cmd/dmap/main.go
@@ -64,8 +64,10 @@ func main() {
 	dlog.Start(ctx, &wg, source.Client)
 
 	if pprof != "" {
-		go http.ListenAndServe(pprof, nil)
-		dlog.Client.Info("Started PProf", pprof)
+		dlog.Client.Info("Starting PProf", pprof)
+		go func() {
+			panic(http.ListenAndServe(pprof, nil))
+		}()
 	}
 
 	client, err := clients.NewMaprClient(args, clients.DefaultMode)
diff --git a/cmd/dserver/main.go b/cmd/dserver/main.go
index 14188e1..3377273 100644
--- a/cmd/dserver/main.go
+++ b/cmd/dserver/main.go
@@ -71,8 +71,10 @@ func main() {
 	dlog.Start(ctx, &wg, source.Server)
 
 	if pprof != "" {
-		dlog.Server.Info("Starting PProf", pprof)
-		go http.ListenAndServe(pprof, nil)
+		dlog.Client.Info("Starting PProf", pprof)
+		go func() {
+			panic(http.ListenAndServe(pprof, nil))
+		}()
 	}
 
 	serv := server.New()
diff --git a/cmd/dtail/main.go b/cmd/dtail/main.go
index bd8eb87..e18923a 100644
--- a/cmd/dtail/main.go
+++ b/cmd/dtail/main.go
@@ -102,8 +102,10 @@ func main() {
 	}
 
 	if pprof != "" {
-		go http.ListenAndServe(pprof, nil)
-		dlog.Client.Info("Started PProf", pprof)
+		dlog.Client.Info("Starting PProf", pprof)
+		go func() {
+			panic(http.ListenAndServe(pprof, nil))
+		}()
 	}
 
 	var client clients.Client
diff --git a/cmd/dtailhealth/main.go b/cmd/dtailhealth/main.go
index 326c43a..a0ca84e 100644
--- a/cmd/dtailhealth/main.go
+++ b/cmd/dtailhealth/main.go
@@ -44,8 +44,10 @@ func main() {
 	dlog.Start(ctx, &wg, source.HealthCheck)
 
 	if pprof != "" {
-		go http.ListenAndServe(pprof, nil)
-		dlog.Client.Info("Started PProf", pprof)
+		dlog.Client.Info("Starting PProf", pprof)
+		go func() {
+			panic(http.ListenAndServe(pprof, nil))
+		}()
 	}
 
 	healthClient, _ := clients.NewHealthClient(args)
diff --git a/integrationtests/commandutils.go b/integrationtests/commandutils.go
index 959288a..8d81955 100644
--- a/integrationtests/commandutils.go
+++ b/integrationtests/commandutils.go
@@ -17,7 +17,7 @@ func runCommand(ctx context.Context, t *testing.T, stdoutFile, cmdStr string,
 	args ...string) (int, error) {
 
 	if _, err := os.Stat(cmdStr); err != nil {
-		return 0, fmt.Errorf("no such executable '%s', please compile first: %v", cmdStr, err)
+		return 0, fmt.Errorf("no such executable '%s', please compile first: %w", cmdStr, err)
 	}
 
 	t.Log("Creating stdout file", stdoutFile)
@@ -31,7 +31,7 @@ func runCommand(ctx context.Context, t *testing.T, stdoutFile, cmdStr string,
 	cmd := exec.CommandContext(ctx, cmdStr, args...)
 	out, err := cmd.CombinedOutput()
 	t.Log("Done running command!", err)
-	fd.Write(out)
+	_, _ = fd.Write(out)
 
 	return exitCodeFromError(err), err
 }
@@ -56,7 +56,7 @@ func startCommand(ctx context.Context, t *testing.T, inPipeFile,
 
 	if _, err := os.Stat(cmdStr); err != nil {
 		return stdoutCh, stderrCh, nil,
-			fmt.Errorf("no such executable '%s', please compile first: %v", cmdStr, err)
+			fmt.Errorf("no such executable '%s', please compile first: %w", cmdStr, err)
 	}
 
 	t.Log(cmdStr, strings.Join(args, " "))
@@ -85,13 +85,13 @@ func startCommand(ctx context.Context, t *testing.T, inPipeFile,
 
 	// Read input file and send to stdin pipe?
 	if inPipeFile != "" {
-		t.Log(fmt.Sprintf("Piping %s to stdin pipe", inPipeFile))
+		t.Logf("Piping %s to stdin pipe", inPipeFile)
 		fd, err := os.Open(inPipeFile)
 		if err != nil {
 			return stdoutCh, stderrCh, nil, err
 		}
 		go func() {
-			io.Copy(stdinPipe, bufio.NewReader(fd))
+			_, _ = io.Copy(stdinPipe, bufio.NewReader(fd))
 			stdinPipe.Close()
 			fd.Close()
 		}()
@@ -135,8 +135,8 @@ func waitForCommand(ctx context.Context, t *testing.T,
 				t.Log(line)
 			}
 		case cmdErr := <-cmdErrCh:
-			t.Log(fmt.Sprintf("Command finished with with exit code %d: %v",
-				exitCodeFromError(cmdErr), cmdErr))
+			t.Logf("Command finished with with exit code %d: %v",
+				exitCodeFromError(cmdErr), cmdErr)
 			return
 		}
 	}
@@ -150,5 +150,5 @@ func exitCodeFromError(err error) int {
 		ws := exitError.Sys().(syscall.WaitStatus)
 		return ws.ExitStatus()
 	}
-	panic(fmt.Sprintf("Unable to get process exit code from error: %v", err))
+	panic(fmt.Errorf("Unable to get process exit code from error: %w", err))
 }
diff --git a/integrationtests/dserver_test.go b/integrationtests/dserver_test.go
index 5b8a091..eaca23b 100644
--- a/integrationtests/dserver_test.go
+++ b/integrationtests/dserver_test.go
@@ -89,8 +89,8 @@ func TestDServer2(t *testing.T) {
 				parts := []string{"INFO", "19801011-424242", "1", "dserver_test.go",
 					"1", "1", "1", "1.0", "1m", "MAPREDUCE:INTEGRATIONTEST",
 					"foo=1", "bar=42"}
-				fd.WriteString(strings.Join(parts, "|"))
-				fd.WriteString("\n")
+				_, _ = fd.WriteString(strings.Join(parts, "|"))
+				_, _ = fd.WriteString("\n")
 			case <-ctx.Done():
 				return
 			}
diff --git a/integrationtests/dtail_test.go b/integrationtests/dtail_test.go
index 64a32f1..752dafb 100644
--- a/integrationtests/dtail_test.go
+++ b/integrationtests/dtail_test.go
@@ -75,8 +75,8 @@ func TestDTailWithServer(t *testing.T) {
 		for {
 			select {
 			case <-time.After(time.Second):
-				fd.WriteString(time.Now().String())
-				fd.WriteString(fmt.Sprintf(" - Hello %s\n", greetings[circular]))
+				_, _ = fd.WriteString(time.Now().String())
+				_, _ = fd.WriteString(fmt.Sprintf(" - Hello %s\n", greetings[circular]))
 				circular = (circular + 1) % len(greetings)
 			case <-ctx.Done():
 				return
@@ -120,8 +120,8 @@ func TestDTailWithServer(t *testing.T) {
 	for i, g := range greetingsRecv {
 		index := (i + offset) % len(greetings)
 		if greetings[index] != g {
-			t.Error(fmt.Sprintf("Expected '%s' but got '%s' at '%v' vs '%v'\n",
-				g, greetings[index], greetings, greetingsRecv))
+			t.Errorf("Expected '%s' but got '%s' at '%v' vs '%v'\n",
+				g, greetings[index], greetings, greetingsRecv)
 			return
 		}
 	}
diff --git a/integrationtests/dtailhealth_test.go b/integrationtests/dtailhealth_test.go
index 49fbd38..7946824 100644
--- a/integrationtests/dtailhealth_test.go
+++ b/integrationtests/dtailhealth_test.go
@@ -20,7 +20,7 @@ func TestDTailHealth1(t *testing.T) {
 	t.Log("Serverless check, is supposed to exit with warning state.")
 	exitCode, err := runCommand(context.TODO(), t, outFile, "../dtailhealth")
 	if exitCode != 1 {
-		t.Error(fmt.Sprintf("Expected exit code '1' but got '%d': %v", exitCode, err))
+		t.Errorf("Expected exit code '1' but got '%d': %v", exitCode, err)
 		return
 	}
 
diff --git a/integrationtests/fileutils.go b/integrationtests/fileutils.go
index d13617d..a1e1051 100644
--- a/integrationtests/fileutils.go
+++ b/integrationtests/fileutils.go
@@ -5,7 +5,6 @@ import (
 	"crypto/sha256"
 	"encoding/base64"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"strings"
@@ -25,7 +24,7 @@ func mapFile(t *testing.T, file string) (map[string]int, error) {
 	scanner.Split(bufio.ScanLines)
 	for scanner.Scan() {
 		line := scanner.Text()
-		count, _ := contents[line]
+		count := contents[line]
 		contents[line] = count + 1
 	}
 
@@ -59,13 +58,11 @@ func compareFilesContents(t *testing.T, fileA, fileB string) error {
 	}
 
 	// The mapreduce result can be in a different order each time (Golang maps are not sorted).
-	t.Log(fmt.Sprintf("Checking whether %s has same lines as file %s (ignoring line order)",
-		fileA, fileB))
+	t.Logf("Checking whether %s has same lines as file %s (ignoring line order)", fileA, fileB)
 	if err := compareMaps(a, b); err != nil {
 		return err
 	}
-	t.Log(fmt.Sprintf("Checking whether %s has same lines as file %s (ignoring line order)",
-		fileB, fileA))
+	t.Logf("Checking whether %s has same lines as file %s (ignoring line order)", fileB, fileA)
 	if err := compareMaps(b, a); err != nil {
 		return err
 	}
@@ -108,7 +105,7 @@ func fileContainsStr(t *testing.T, file, str string) error {
 }
 
 func shaOfFile(t *testing.T, file string) string {
-	bytes, err := ioutil.ReadFile(file)
+	bytes, err := os.ReadFile(file)
 	if err != nil {
 		t.Error(err)
 	}
diff --git a/internal/clients/baseclient.go b/internal/clients/baseclient.go
index 3025f72..013f2f2 100644
--- a/internal/clients/baseclient.go
+++ b/internal/clients/baseclient.go
@@ -20,8 +20,6 @@ type baseClient struct {
 	config.Args
 	// To display client side stats
 	stats *stats
-	// List of remote servers to connect to.
-	servers []string
 	// We have one connection per remote server.
 	connections []connectors.Connector
 	// SSH auth methods to use to connect to the remote servers.
diff --git a/internal/clients/connectors/serverconnection.go b/internal/clients/connectors/serverconnection.go
index aeb2a41..5c3d455 100644
--- a/internal/clients/connectors/serverconnection.go
+++ b/internal/clients/connectors/serverconnection.go
@@ -172,25 +172,31 @@ func (c *ServerConnection) handle(ctx context.Context, cancel context.CancelFunc
 	}
 
 	go func() {
-		io.Copy(stdinPipe, c.handler)
-		cancel()
+		defer cancel()
+		if _, err := io.Copy(stdinPipe, c.handler); err != nil {
+			dlog.Client.Trace(err)
+		}
 	}()
 	go func() {
-		io.Copy(c.handler, stdoutPipe)
-		cancel()
+		defer cancel()
+		if _, err := io.Copy(c.handler, stdoutPipe); err != nil {
+			dlog.Client.Trace(err)
+		}
 	}()
 	go func() {
+		defer cancel()
 		select {
 		case <-c.handler.Done():
 		case <-ctx.Done():
 		}
-		cancel()
 	}()
 
 	// Send all commands to client.
 	for _, command := range c.commands {
 		dlog.Client.Debug(command)
-		c.handler.SendMessage(command)
+		if err := c.handler.SendMessage(command); err != nil {
+			dlog.Client.Debug(err)
+		}
 	}
 
 	if !c.throttlingDone {
diff --git a/internal/clients/connectors/serverless.go b/internal/clients/connectors/serverless.go
index 431247a..631186a 100644
--- a/internal/clients/connectors/serverless.go
+++ b/internal/clients/connectors/serverless.go
@@ -83,29 +83,35 @@ func (s *Serverless) handle(ctx context.Context, cancel context.CancelFunc) erro
 	}
 
 	go func() {
-		io.Copy(serverHandler, s.handler)
+		defer terminate()
+		if _, err := io.Copy(serverHandler, s.handler); err != nil {
+			dlog.Client.Trace(err)
+		}
 		dlog.Client.Trace("io.Copy(serverHandler, s.handler) => done")
-		terminate()
 	}()
 	go func() {
-		io.Copy(s.handler, serverHandler)
+		defer terminate()
+		if _, err := io.Copy(s.handler, serverHandler); err != nil {
+			dlog.Client.Trace(err)
+		}
 		dlog.Client.Trace("io.Copy(s.handler, serverHandler) => done")
-		terminate()
 	}()
 	go func() {
+		defer terminate()
 		select {
 		case <-s.handler.Done():
 			dlog.Client.Trace("<-s.handler.Done()")
 		case <-ctx.Done():
 			dlog.Client.Trace("<-ctx.Done()")
 		}
-		terminate()
 	}()
 
 	// Send all commands to client.
 	for _, command := range s.commands {
 		dlog.Client.Debug("Sending command to serverless server", command)
-		s.handler.SendMessage(command)
+		if err := s.handler.SendMessage(command); err != nil {
+			dlog.Client.Debug(err)
+		}
 	}
 
 	<-ctx.Done()
diff --git a/internal/clients/maprclient.go b/internal/clients/maprclient.go
index 6362028..2bc66a4 100644
--- a/internal/clients/maprclient.go
+++ b/internal/clients/maprclient.go
@@ -82,7 +82,7 @@ func NewMaprClient(args config.Args, maprClientMode MaprClientMode) (*MaprClient
 	case "", ".":
 		c.RegexStr = "."
 	case "*":
-		c.RegexStr = fmt.Sprintf("\\|MAPREDUCE:\\|")
+		c.RegexStr = "\\|MAPREDUCE:\\|"
 	default:
 		c.RegexStr = fmt.Sprintf("\\|MAPREDUCE:%s\\|", c.query.Table)
 	}
diff --git a/internal/clients/stats.go b/internal/clients/stats.go
index 2da3cf7..7a6643b 100644
--- a/internal/clients/stats.go
+++ b/internal/clients/stats.go
@@ -89,7 +89,7 @@ func (s *stats) printStatsDueInterrupt(messages []string) {
 			))
 			continue
 		}
-		fmt.Println(fmt.Sprintf(" %s", message))
+		fmt.Printf(" %s\n", message)
 	}
 	time.Sleep(time.Second * time.Duration(config.InterruptTimeoutS))
 	dlog.Client.Resume()
@@ -128,12 +128,6 @@ func (s *stats) statsLine(connected, newConnections int, throttle int) string {
 	return sb.String()
 }
 
-func (s *stats) numConnected() int {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return s.connected
-}
-
 func percentOf(total float64, value float64) float64 {
 	if total == 0 || total == value {
 		return 100
diff --git a/internal/config/initializer.go b/internal/config/initializer.go
index 9724902..9c3bf64 100644
--- a/internal/config/initializer.go
+++ b/internal/config/initializer.go
@@ -4,7 +4,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"strings"
 
@@ -34,8 +34,11 @@ func (in *initializer) parseConfig(args *Args) error {
 		paths = append(paths, fmt.Sprintf("%s/.config/dtail/dtail.conf", homeDir))
 		paths = append(paths, fmt.Sprintf("%s/.dtail.conf", homeDir))
 		for _, configPath := range paths {
-			if _, err := os.Stat(configPath); !os.IsNotExist(err) {
-				in.parseSpecificConfig(configPath)
+			if _, err := os.Stat(configPath); os.IsNotExist(err) {
+				continue
+			}
+			if err := in.parseSpecificConfig(configPath); err != nil {
+				return err
 			}
 		}
 	}
@@ -46,17 +49,17 @@ func (in *initializer) parseConfig(args *Args) error {
 func (in *initializer) parseSpecificConfig(configFile string) error {
 	fd, err := os.Open(configFile)
 	if err != nil {
-		return fmt.Errorf("Unable to read config file: %v", err)
+		return fmt.Errorf("Unable to read config file: %w", err)
 	}
 	defer fd.Close()
 
-	cfgBytes, err := ioutil.ReadAll(fd)
+	cfgBytes, err := io.ReadAll(fd)
 	if err != nil {
-		return fmt.Errorf("Unable to read config file %s: %v", configFile, err)
+		return fmt.Errorf("Unable to read config file %s: %w", configFile, err)
 	}
 
 	if err := json.Unmarshal([]byte(cfgBytes), in); err != nil {
-		return fmt.Errorf("Unable to parse config file %s: %v", configFile, err)
+		return fmt.Errorf("Unable to parse config file %s: %w", configFile, err)
 	}
 
 	return nil
@@ -116,7 +119,9 @@ func (in *initializer) setupConfig(sourceCb transformCb, args *Args,
 	}
 
 	setupLogDirectory(in)
-	sourceCb(in, args, additionalArgs)
+	if err := sourceCb(in, args, additionalArgs); err != nil {
+		return err
+	}
 	if args.Plain {
 		setupPlainMode(in, args)
 	}
diff --git a/internal/io/dlog/dlog.go b/internal/io/dlog/dlog.go
index c5ab8f8..258fb68 100644
--- a/internal/io/dlog/dlog.go
+++ b/internal/io/dlog/dlog.go
@@ -3,7 +3,6 @@ package dlog
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -225,14 +224,14 @@ func (d *DLog) Mapreduce(table string, data map[string]interface{}) string {
 		// level|date-time|process|caller|cpus|goroutines|cgocalls|loadavg|uptime|MAPREDUCE:TABLE|key=value|...
 
 		var loadAvg string
-		if loadAvgBytes, err := ioutil.ReadFile("/proc/loadavg"); err == nil {
+		if loadAvgBytes, err := os.ReadFile("/proc/loadavg"); err == nil {
 			tmp := string(loadAvgBytes)
 			s := strings.SplitN(tmp, " ", 2)
 			loadAvg = s[0]
 		}
 
 		var uptime string
-		if uptimeBytes, err := ioutil.ReadFile("/proc/uptime"); err == nil {
+		if uptimeBytes, err := os.ReadFile("/proc/uptime"); err == nil {
 			tmp := string(uptimeBytes)
 			s := strings.SplitN(tmp, ".", 2)
 			i, _ := strconv.ParseInt(s[0], 10, 64)
diff --git a/internal/io/dlog/loggers/file.go b/internal/io/dlog/loggers/file.go
index 6a09353..8e567bc 100644
--- a/internal/io/dlog/loggers/file.go
+++ b/internal/io/dlog/loggers/file.go
@@ -12,8 +12,6 @@ import (
 	"github.com/mimecast/dtail/internal/config"
 )
 
-type fileWriter struct{}
-
 type fileMessageBuf struct {
 	now     time.Time
 	message string
@@ -124,9 +122,10 @@ func (f *file) write(m *fileMessageBuf) {
 		writer = f.getWriter(f.strategy.FileBase)
 	}
 
-	writer.WriteString(m.message)
+	// Don't report any error, we won't be able to log it anyway!
+	_, _ = writer.WriteString(m.message)
 	if m.nl {
-		writer.WriteByte('\n')
+		_ = writer.WriteByte('\n')
 	}
 }
 
diff --git a/internal/io/dlog/loggers/stdout.go b/internal/io/dlog/loggers/stdout.go
index ef30855..b024243 100644
--- a/internal/io/dlog/loggers/stdout.go
+++ b/internal/io/dlog/loggers/stdout.go
@@ -69,4 +69,4 @@ func (s *stdout) Rotate() {
 	// This is empty because it isn't doing anything but has to satisfy the interface.
 }
 
-func (stdout) SupportsColors() bool { return true }
+func (*stdout) SupportsColors() bool { return true }
diff --git a/internal/io/fs/readfile.go b/internal/io/fs/readfile.go
index 669f99f..dc1d8ea 100644
--- a/internal/io/fs/readfile.go
+++ b/internal/io/fs/readfile.go
@@ -116,23 +116,19 @@ func (f *readFile) makeReader() (*bufio.Reader, *os.File, error) {
 	return f.makeFileReader()
 }
 
-func (f *readFile) makeFileReader() (*bufio.Reader, *os.File, error) {
-	var reader *bufio.Reader
-	fd, err := os.Open(f.filePath)
-	if err != nil {
-		return reader, fd, err
+func (f *readFile) makeFileReader() (reader *bufio.Reader, fd *os.File, err error) {
+	if fd, err = os.Open(f.filePath); err != nil {
+		return
 	}
 
 	if f.seekEOF {
-		fd.Seek(0, io.SeekEnd)
+		if _, err = fd.Seek(0, io.SeekEnd); err != nil {
+			return
+		}
 	}
 
 	reader, err = f.makeCompressedFileReader(fd)
-	if err != nil {
-		return reader, fd, err
-	}
-
-	return reader, fd, nil
+	return
 }
 
 func (f *readFile) makePipeReader() (*bufio.Reader, *os.File, error) {
@@ -249,7 +245,7 @@ func (f *readFile) truncated(fd *os.File) (bool, error) {
 	dlog.Common.Debug(f.filePath, "File truncation check")
 
 	// Can not seek currently open FD.
-	currentPosition, err := fd.Seek(0, os.SEEK_CUR)
+	currentPosition, err := fd.Seek(0, io.SeekCurrent)
 	if err != nil {
 		return true, err
 	}
diff --git a/internal/io/fs/readfilelcontext.go b/internal/io/fs/readfilelcontext.go
index 44ce17d..87d59d6 100644
--- a/internal/io/fs/readfilelcontext.go
+++ b/internal/io/fs/readfilelcontext.go
@@ -31,22 +31,17 @@ type ltxState struct {
 func (f *readFile) filterWithoutLContext(ctx context.Context, rawLines <-chan *bytes.Buffer,
 	lines chan<- *line.Line, re regex.Regex) {
 
-	for {
-		select {
-		case rawLine, ok := <-rawLines:
-			f.updatePosition()
-			if !ok {
+	for rawLine := range rawLines {
+		f.updatePosition()
+		if newLine, ok := f.transmittable(rawLine, len(lines), cap(lines), re); ok {
+			select {
+			case lines <- newLine:
+			case <-ctx.Done():
 				return
 			}
-			if newLine, ok := f.transmittable(rawLine, len(lines), cap(lines), re); ok {
-				select {
-				case lines <- newLine:
-				case <-ctx.Done():
-					return
-				}
-			}
 		}
 	}
+	f.updatePosition()
 }
 
 // Filter log lines matching a given regular expression, however with local grep context.
diff --git a/internal/mapr/client/aggregate.go b/internal/mapr/client/aggregate.go
index 1704d43..2e9b61a 100644
--- a/internal/mapr/client/aggregate.go
+++ b/internal/mapr/client/aggregate.go
@@ -44,7 +44,7 @@ func (a *Aggregate) Aggregate(message string) error {
 	groupKey := parts[0]
 	samples, err := strconv.Atoi(parts[1])
 	if err != nil {
-		return fmt.Errorf("unable to parse sample count '%s': %v", parts[1], err)
+		return fmt.Errorf("unable to parse sample count '%s': %w", parts[1], err)
 	}
 
 	fields := a.makeFields(parts[2:])
diff --git a/internal/mapr/fieldtypes.go b/internal/mapr/fieldtypes.go
index a64efd1..4242407 100644
--- a/internal/mapr/fieldtypes.go
+++ b/internal/mapr/fieldtypes.go
@@ -1,7 +1,5 @@
 package mapr
 
-import "fmt"
-
 type fieldType int
 
 // The possible field types.
@@ -16,14 +14,14 @@ const (
 func (w fieldType) String() string {
 	switch w {
 	case Field:
-		return fmt.Sprintf("Field")
+		return "Field"
 	case String:
-		return fmt.Sprintf("String")
+		return "String"
 	case Float:
-		return fmt.Sprintf("Float")
+		return "Float"
 	case FunctionStack:
-		return fmt.Sprintf("FunctionStack")
+		return "FunctionStack"
 	default:
-		return fmt.Sprintf("UndefFieldType")
+		return "UndefFieldType"
 	}
 }
diff --git a/internal/mapr/groupsetresult.go b/internal/mapr/groupsetresult.go
index d01a3c9..58663b8 100644
--- a/internal/mapr/groupsetresult.go
+++ b/internal/mapr/groupsetresult.go
@@ -169,9 +169,10 @@ func (*GroupSet) writeQueryFile(query *Query) error {
 	}
 	defer fd.Close()
 
-	fd.WriteString(query.RawQuery)
-	os.Rename(tmpQueryFile, queryFile)
-	return nil
+	if _, err := fd.WriteString(query.RawQuery); err != nil {
+		return err
+	}
+	return os.Rename(tmpQueryFile, queryFile)
 }
 
 // WriteResult writes the result to an CSV outfile.
@@ -221,7 +222,9 @@ func (g *GroupSet) resultWriteUnformatted(query *Query, rows []result, fd *os.Fi
 	lastColumn := len(query.Select) - 1
 
 	if writeHeader {
-		g.resultWriteUnformattedHeader(query, fd, lastColumn)
+		if err := g.resultWriteUnformattedHeader(query, fd, lastColumn); err != nil {
+			return err
+		}
 	}
 
 	// And now write the data
@@ -230,13 +233,19 @@ func (g *GroupSet) resultWriteUnformatted(query *Query, rows []result, fd *os.Fi
 			break
 		}
 		for j, value := range r.values {
-			fd.WriteString(value)
+			if _, err := fd.WriteString(value); err != nil {
+				return err
+			}
 			if j == lastColumn {
 				continue
 			}
-			fd.WriteString(protocol.CSVDelimiter)
+			if _, err := fd.WriteString(protocol.CSVDelimiter); err != nil {
+				return err
+			}
+		}
+		if _, err := fd.WriteString("\n"); err != nil {
+			return err
 		}
-		fd.WriteString("\n")
 	}
 
 	if !query.Outfile.AppendMode {
@@ -250,13 +259,18 @@ func (g *GroupSet) resultWriteUnformatted(query *Query, rows []result, fd *os.Fi
 	return nil
 }
 
-func (g *GroupSet) resultWriteUnformattedHeader(query *Query, fd *os.File, lastColumn int) {
+func (g *GroupSet) resultWriteUnformattedHeader(query *Query, fd *os.File, lastColumn int) (err error) {
 	for i, sc := range query.Select {
-		fd.WriteString(sc.FieldStorage)
+		if _, err = fd.WriteString(sc.FieldStorage); err != nil {
+			return
+		}
 		if i == lastColumn {
 			continue
 		}
-		fd.WriteString(protocol.CSVDelimiter)
+		if _, err = fd.WriteString(protocol.CSVDelimiter); err != nil {
+			return
+		}
 	}
-	fd.WriteString("\n")
+	_, err = fd.WriteString("\n")
+	return
 }
diff --git a/internal/mapr/query.go b/internal/mapr/query.go
index ddcbc90..139f04c 100644
--- a/internal/mapr/query.go
+++ b/internal/mapr/query.go
@@ -133,7 +133,7 @@ func (q *Query) parseTokens(tokens []token) ([]token, error) {
 	var err error
 	var found []token
 
-	for tokens != nil && len(tokens) > 0 {
+	for len(tokens) > 0 {
 		switch strings.ToLower(tokens[0].str) {
 		case "select":
 			tokens, found = tokensConsume(tokens[1:])
diff --git a/internal/mapr/token.go b/internal/mapr/token.go
index 48d1192..77362f7 100644
--- a/internal/mapr/token.go
+++ b/internal/mapr/token.go
@@ -99,7 +99,8 @@ func tokensConsumeOptional(tokens []token, optional string) []token {
 	if len(tokens) < 1 {
 		return tokens
 	}
-	if strings.ToLower(tokens[0].str) == strings.ToLower(optional) {
+	//if strings.ToLower(tokens[0].str) == strings.ToLower(optional) {
+	if strings.EqualFold(tokens[0].str, optional) {
 		return tokens[1:]
 	}
 	return tokens
diff --git a/internal/server/handlers/basehandler.go b/internal/server/handlers/basehandler.go
index 7daf071..f6ab3db 100644
--- a/internal/server/handlers/basehandler.go
+++ b/internal/server/handlers/basehandler.go
@@ -130,7 +130,7 @@ func (h *baseHandler) Write(p []byte) (n int, err error) {
 	for _, b := range p {
 		switch b {
 		case ';':
-			h.handleCommand(string(h.writeBuf.Bytes()))
+			h.handleCommand(h.writeBuf.String())
 			h.writeBuf.Reset()
 		default:
 			h.writeBuf.WriteByte(b)
@@ -252,15 +252,15 @@ func (h *baseHandler) handleOptions(options map[string]string) {
 	// We can read the options only once, will cause a data race otherwise if
 	// changed multiple times for multiple incoming commands.
 	h.once.Do(func() {
-		if quiet, _ := options["quiet"]; quiet == "true" {
+		if quiet := options["quiet"]; quiet == "true" {
 			dlog.Server.Debug(h.user, "Enabling quiet mode")
 			h.quiet = true
 		}
-		if plain, _ := options["plain"]; plain == "true" {
+		if plain := options["plain"]; plain == "true" {
 			dlog.Server.Debug(h.user, "Enabling plain mode")
 			h.plain = true
 		}
-		if serverless, _ := options["serverless"]; serverless == "true" {
+		if serverless := options["serverless"]; serverless == "true" {
 			dlog.Server.Debug(h.user, "Enabling serverless mode")
 			h.serverless = true
 		}
diff --git a/internal/server/server.go b/internal/server/server.go
index 761880d..8b581b1 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -130,7 +130,9 @@ func (s *Server) handleChannel(ctx context.Context, sshConn gossh.Conn,
 	user, err := user.New(sshConn.User(), sshConn.RemoteAddr().String())
 	if err != nil {
 		dlog.Server.Error(user, err)
-		newChannel.Reject(gossh.Prohibited, err.Error())
+		if err := newChannel.Reject(gossh.Prohibited, err.Error()); err != nil {
+			dlog.Server.Debug(err)
+		}
 		return
 	}
 
@@ -138,7 +140,9 @@ func (s *Server) handleChannel(ctx context.Context, sshConn gossh.Conn,
 	if newChannel.ChannelType() != "session" {
 		err := errors.New("Don'w allow other channel types than session")
 		dlog.Server.Error(user, err)
-		newChannel.Reject(gossh.Prohibited, err.Error())
+		if err := newChannel.Reject(gossh.Prohibited, err.Error()); err != nil {
+			dlog.Server.Debug(err)
+		}
 		return
 	}
 
@@ -160,7 +164,9 @@ func (s *Server) handleRequests(ctx context.Context, sshConn gossh.Conn,
 	dlog.Server.Info(user, "Invoking request handler")
 	for req := range in {
 		var payload = struct{ Value string }{}
-		gossh.Unmarshal(req.Payload, &payload)
+		if err := gossh.Unmarshal(req.Payload, &payload); err != nil {
+			dlog.Server.Error(user, err)
+		}
 
 		switch req.Type {
 		case "shell":
@@ -177,14 +183,18 @@ func (s *Server) handleRequests(ctx context.Context, sshConn gossh.Conn,
 			}
 
 			go func() {
+				defer terminate()
 				// Broken pipe, cancel
-				io.Copy(channel, handler)
-				terminate()
+				if _, err := io.Copy(channel, handler); err != nil {
+					dlog.Server.Trace(user, fmt.Errorf("channel->handler: %w", err))
+				}
 			}()
 			go func() {
+				defer terminate()
 				// Broken pipe, cancel
-				io.Copy(handler, channel)
-				terminate()
+				if _, err := io.Copy(handler, channel); err != nil {
+					dlog.Server.Trace(user, fmt.Errorf("handler->channel: %w", err))
+				}
 			}()
 			go func() {
 				select {
@@ -203,9 +213,13 @@ func (s *Server) handleRequests(ctx context.Context, sshConn gossh.Conn,
 			}()
 
 			// Only serving shell type
-			req.Reply(true, nil)
+			if err := req.Reply(true, nil); err != nil {
+				dlog.Server.Trace(user, fmt.Errorf("reply(true): %w", err))
+			}
 		default:
-			req.Reply(false, nil)
+			if err := req.Reply(false, nil); err != nil {
+				dlog.Server.Trace(user, fmt.Errorf("reply(false): %w", err))
+			}
 			return fmt.Errorf("Closing SSH connection as unknown request received|%s|%v",
 				req.Type, payload.Value)
 		}
diff --git a/internal/ssh/client/clientkeypair.go b/internal/ssh/client/clientkeypair.go
index b35b25d..20cdc88 100644
--- a/internal/ssh/client/clientkeypair.go
+++ b/internal/ssh/client/clientkeypair.go
@@ -6,7 +6,6 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
-	"io/ioutil"
 	"os"
 
 	"github.com/mimecast/dtail/internal/io/dlog"
@@ -83,7 +82,7 @@ func generatePublicKey(privatekey *rsa.PublicKey) ([]byte, error) {
 }
 
 func writeKey(keyBytes []byte, saveFileTo string) error {
-	err := ioutil.WriteFile(saveFileTo, keyBytes, 0600)
+	err := os.WriteFile(saveFileTo, keyBytes, 0600)
 	if err != nil {
 		return err
 	}
diff --git a/internal/ssh/client/knownhostscallback.go b/internal/ssh/client/knownhostscallback.go
index 393c4c7..fe3543c 100644
--- a/internal/ssh/client/knownhostscallback.go
+++ b/internal/ssh/client/knownhostscallback.go
@@ -232,8 +232,12 @@ func (c KnownHostsCallback) trustHosts(hosts []unknownHost) {
 		// And once as [IP]:PORT
 		addresses[knownhosts.Normalize(unknown.remote.String())] = struct{}{}
 
-		newFd.WriteString(fmt.Sprintf("%s\n", unknown.hostLine))
-		newFd.WriteString(fmt.Sprintf("%s\n", unknown.ipLine))
+		if _, err := newFd.WriteString(fmt.Sprintf("%s\n", unknown.hostLine)); err != nil {
+			panic(err)
+		}
+		if _, err := newFd.WriteString(fmt.Sprintf("%s\n", unknown.ipLine)); err != nil {
+			panic(err)
+		}
 	}
 
 	// Read old known hosts file, to see which are old and new entries
diff --git a/internal/ssh/server/hostkey.go b/internal/ssh/server/hostkey.go
index be23d85..b2d4569 100644
--- a/internal/ssh/server/hostkey.go
+++ b/internal/ssh/server/hostkey.go
@@ -1,7 +1,6 @@
 package server
 
 import (
-	"io/ioutil"
 	"os"
 
 	"github.com/mimecast/dtail/internal/config"
@@ -26,7 +25,7 @@ func PrivateHostKey() []byte {
 		}
 
 		pem := ssh.EncodePrivateKeyToPEM(privateKey)
-		if err := ioutil.WriteFile(hostKeyFile, pem, 0600); err != nil {
+		if err := os.WriteFile(hostKeyFile, pem, 0600); err != nil {
 			dlog.Server.Error("Unable to write private server RSA host key to file",
 				hostKeyFile, err)
 		}
@@ -34,7 +33,7 @@ func PrivateHostKey() []byte {
 	}
 
 	dlog.Server.Info("Reading private server RSA host key from file", hostKeyFile)
-	pem, err := ioutil.ReadFile(hostKeyFile)
+	pem, err := os.ReadFile(hostKeyFile)
 	if err != nil {
 		dlog.Server.FatalPanic("Failed to load private server RSA host key", err)
 	}
diff --git a/internal/ssh/server/publickeycallback.go b/internal/ssh/server/publickeycallback.go
index f7655b4..bcc9004 100644
--- a/internal/ssh/server/publickeycallback.go
+++ b/internal/ssh/server/publickeycallback.go
@@ -2,7 +2,6 @@ package server
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	goUser "os/user"
 
@@ -30,7 +29,7 @@ func PublicKeyCallback(c gossh.ConnMetadata,
 	}
 
 	dlog.Server.Info(user, "Reading", authorizedKeysFile)
-	authorizedKeysBytes, err := ioutil.ReadFile(authorizedKeysFile)
+	authorizedKeysBytes, err := os.ReadFile(authorizedKeysFile)
 	if err != nil {
 		return nil, fmt.Errorf("Unable to read authorized keys file|%s|%s|%s",
 			authorizedKeysFile, user, err.Error())
diff --git a/internal/ssh/ssh.go b/internal/ssh/ssh.go
index db5aaf1..9c2dcb8 100644
--- a/internal/ssh/ssh.go
+++ b/internal/ssh/ssh.go
@@ -6,7 +6,6 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 	"syscall"
@@ -15,7 +14,7 @@ import (
 
 	gossh "golang.org/x/crypto/ssh"
 	"golang.org/x/crypto/ssh/agent"
-	"golang.org/x/crypto/ssh/terminal"
+	"golang.org/x/term"
 )
 
 // GeneratePrivateRSAKey is used by the server to generate its key.
@@ -63,7 +62,7 @@ func Agent() (gossh.AuthMethod, error) {
 // EnterKeyPhrase is required to read phrase protected private keys.
 func EnterKeyPhrase(keyFile string) []byte {
 	fmt.Printf("Enter phrase for key %s: ", keyFile)
-	phrase, err := terminal.ReadPassword(int(syscall.Stdin))
+	phrase, err := term.ReadPassword(int(syscall.Stdin))
 	if err != nil {
 		panic(err)
 	}
@@ -73,7 +72,7 @@ func EnterKeyPhrase(keyFile string) []byte {
 
 // KeyFile returns the key as a SSH auth method.
 func KeyFile(keyFile string) (gossh.AuthMethod, error) {
-	buffer, err := ioutil.ReadFile(keyFile)
+	buffer, err := os.ReadFile(keyFile)
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/user/server/user.go b/internal/user/server/user.go
index abf74f3..d391672 100644
--- a/internal/user/server/user.go
+++ b/internal/user/server/user.go
@@ -81,7 +81,7 @@ func (u *User) HasFilePermission(filePath, permissionType string) (hasPermission
 func (u *User) hasFilePermission(cleanPath, permissionType string) (bool, error) {
 	// First check file system Linux/UNIX permission.
 	if _, err := permissions.ToRead(u.Name, cleanPath); err != nil {
-		return false, fmt.Errorf("User without OS file system permissions to read path: '%v'", err)
+		return false, fmt.Errorf("User without OS file system permissions to read path: %w", err)
 	}
 	dlog.Server.Info(u, cleanPath, permissionType,
 		"User with OS file system permissions to path")
@@ -89,7 +89,7 @@ func (u *User) hasFilePermission(cleanPath, permissionType string) (bool, error)
 	// Only allow to follow regular files or symlinks.
 	info, err := os.Lstat(cleanPath)
 	if err != nil {
-		return false, fmt.Errorf("Unable to determine file type: '%v'", err)
+		return false, fmt.Errorf("Unable to determine file type: %w", err)
 	}
 	if !info.Mode().IsRegular() {
 		return false, fmt.Errorf("Can only open regular files or follow symlinks")
@@ -130,7 +130,7 @@ func (u *User) iteratePaths(cleanPath, permissionType string) (bool, error) {
 		re, err := regexp.Compile(regexStr)
 		if err != nil {
 			return false, fmt.Errorf("Permission test failed, can't compile regex "+
-				"'%s': '%v'", regexStr, err)
+				"'%s': %w", regexStr, err)
 		}
 		if negate && re.MatchString(cleanPath) {
 			dlog.Server.Info(u, cleanPath, "Permission test failed partially, "+
diff --git a/internal/version/version.go b/internal/version/version.go
index 15ea50f..c8ad394 100644
--- a/internal/version/version.go
+++ b/internal/version/version.go
@@ -13,7 +13,7 @@ const (
 	// Name of DTail.
 	Name string = "DTail"
 	// Version of DTail.
-	Version string = "4.3.0"
+	Version string = "4.3.2"
 	// Additional information for DTail
 	Additional string = "Have a lot of fun!"
 )