all: use errors.As instead of type assertion for detecting net.Error

lib/backup/s3remote/s3.go

@@ -3,6 +3,7 @@ package s3remote
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"strings"
@@ -287,7 +288,8 @@ func (fs *FS) HasFile(filePath string) (bool, error) {
 	}
 	o, err := fs.s3.GetObject(input)
 	if err != nil {
-		if ae, ok := err.(awserr.Error); ok && ae.Code() == s3.ErrCodeNoSuchKey {
+		var ae awserr.Error
+		if errors.As(err, &ae) && ae.Code() == s3.ErrCodeNoSuchKey {
 			return false, nil
 		}
 		return false, fmt.Errorf("cannot open %q at %s (remote path %q): %w", filePath, fs, path, err)

lib/ingestserver/graphite/server.go

@@ -1,6 +1,7 @@
 package graphite
 
 import (
+	"errors"
 	"io"
 	"net"
 	"runtime"
@@ -86,7 +87,8 @@ func serveTCP(ln net.Listener, insertHandler func(r io.Reader) error) {
 	for {
 		c, err := ln.Accept()
 		if err != nil {
-			if ne, ok := err.(net.Error); ok {
+			var ne net.Error
+			if errors.As(err, &ne) {
 				if ne.Temporary() {
 					logger.Errorf("graphite: temporary error when listening for TCP addr %q: %s", ln.Addr(), err)
 					time.Sleep(time.Second)
@@ -125,7 +127,8 @@ func serveUDP(ln net.PacketConn, insertHandler func(r io.Reader) error) {
 				n, addr, err := ln.ReadFrom(bb.B)
 				if err != nil {
 					writeErrorsUDP.Inc()
-					if ne, ok := err.(net.Error); ok {
+					var ne net.Error
+					if errors.As(err, &ne) {
 						if ne.Temporary() {
 							logger.Errorf("graphite: temporary error when listening for UDP addr %q: %s", ln.LocalAddr(), err)
 							time.Sleep(time.Second)

lib/ingestserver/influx/server.go

@@ -1,6 +1,7 @@
 package influx
 
 import (
+	"errors"
 	"io"
 	"net"
 	"runtime"
@@ -86,7 +87,8 @@ func serveTCP(ln net.Listener, insertHandler func(r io.Reader) error) {
 	for {
 		c, err := ln.Accept()
 		if err != nil {
-			if ne, ok := err.(net.Error); ok {
+			var ne net.Error
+			if errors.As(err, &ne) {
 				if ne.Temporary() {
 					logger.Errorf("influx: temporary error when listening for TCP addr %q: %s", ln.Addr(), err)
 					time.Sleep(time.Second)
@@ -125,7 +127,8 @@ func serveUDP(ln net.PacketConn, insertHandler func(r io.Reader) error) {
 				n, addr, err := ln.ReadFrom(bb.B)
 				if err != nil {
 					writeErrorsUDP.Inc()
-					if ne, ok := err.(net.Error); ok {
+					var ne net.Error
+					if errors.As(err, &ne) {
 						if ne.Temporary() {
 							logger.Errorf("influx: temporary error when listening for UDP addr %q: %s", ln.LocalAddr(), err)
 							time.Sleep(time.Second)

lib/ingestserver/opentsdb/listener_switch.go

@@ -1,6 +1,7 @@
 package opentsdb
 
 import (
+	"errors"
 	"io"
 	"net"
 	"sync"
@@ -64,7 +65,8 @@ func (ls *listenerSwitch) worker() {
 	for {
 		c, err := ls.ln.Accept()
 		if err != nil {
-			if ne, ok := err.(net.Error); ok && ne.Temporary() {
+			var ne net.Error
+			if errors.As(err, &ne) && ne.Temporary() {
 				logger.Infof("listenerSwitch: temporary error at %q: %s; sleeping for a second...", ls.ln.Addr(), err)
 				time.Sleep(time.Second)
 				continue

lib/ingestserver/opentsdb/server.go

@@ -1,6 +1,7 @@
 package opentsdb
 
 import (
+	"errors"
 	"io"
 	"net"
 	"net/http"
@@ -106,7 +107,8 @@ func serveTelnet(ln net.Listener, insertHandler func(r io.Reader) error) {
 	for {
 		c, err := ln.Accept()
 		if err != nil {
-			if ne, ok := err.(net.Error); ok {
+			var ne net.Error
+			if errors.As(err, &ne) {
 				if ne.Temporary() {
 					logger.Errorf("opentsdb: temporary error when listening for TCP addr %q: %s", ln.Addr(), err)
 					time.Sleep(time.Second)
@@ -145,7 +147,8 @@ func serveUDP(ln net.PacketConn, insertHandler func(r io.Reader) error) {
 				n, addr, err := ln.ReadFrom(bb.B)
 				if err != nil {
 					writeErrorsUDP.Inc()
-					if ne, ok := err.(net.Error); ok {
+					var ne net.Error
+					if errors.As(err, &ne) {
 						if ne.Temporary() {
 							logger.Errorf("opentsdb: temporary error when listening for UDP addr %q: %s", ln.LocalAddr(), err)
 							time.Sleep(time.Second)

lib/netutil/conn.go

@@ -1,6 +1,7 @@
 package netutil
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -57,7 +58,8 @@ func (sc *statConn) Read(p []byte) (int, error) {
 	sc.cm.readCalls.Inc()
 	sc.cm.readBytes.Add(n)
 	if err != nil && err != io.EOF {
-		if ne, ok := err.(net.Error); ok && ne.Timeout() {
+		var ne net.Error
+		if errors.As(err, &ne) && ne.Timeout() {
 			sc.cm.readTimeouts.Inc()
 		} else {
 			sc.cm.readErrors.Inc()
@@ -71,7 +73,8 @@ func (sc *statConn) Write(p []byte) (int, error) {
 	sc.cm.writeCalls.Inc()
 	sc.cm.writtenBytes.Add(n)
 	if err != nil {
-		if ne, ok := err.(net.Error); ok && ne.Timeout() {
+		var ne net.Error
+		if errors.As(err, &ne) && ne.Timeout() {
 			sc.cm.writeTimeouts.Inc()
 		} else {
 			sc.cm.writeErrors.Inc()

lib/netutil/tcplistener.go

@@ -1,6 +1,7 @@
 package netutil
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"net"
@@ -63,7 +64,8 @@ func (ln *TCPListener) Accept() (net.Conn, error) {
 		conn, err := ln.Listener.Accept()
 		ln.accepts.Inc()
 		if err != nil {
-			if ne, ok := err.(net.Error); ok && ne.Temporary() {
+			var ne net.Error
+			if errors.As(err, &ne) && ne.Temporary() {
 				logger.Errorf("temporary error when listening for TCP addr %q: %s", ln.Addr(), err)
 				time.Sleep(time.Second)
 				continue

lib/protoparser/graphite/streamparser.go

@@ -1,6 +1,7 @@
 package graphite
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -53,7 +54,8 @@ func (ctx *streamContext) Read(r io.Reader) bool {
 	}
 	ctx.reqBuf, ctx.tailBuf, ctx.err = common.ReadLinesBlock(r, ctx.reqBuf, ctx.tailBuf)
 	if ctx.err != nil {
-		if ne, ok := ctx.err.(net.Error); ok && ne.Timeout() {
+		var ne net.Error
+		if errors.As(ctx.err, &ne) && ne.Timeout() {
 			// Flush the read data on timeout and try reading again.
 			ctx.err = nil
 		} else {

lib/protoparser/opentsdb/streamparser.go

@@ -1,6 +1,7 @@
 package opentsdb
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -52,7 +53,8 @@ func (ctx *streamContext) Read(r io.Reader) bool {
 	}
 	ctx.reqBuf, ctx.tailBuf, ctx.err = common.ReadLinesBlock(r, ctx.reqBuf, ctx.tailBuf)
 	if ctx.err != nil {
-		if ne, ok := ctx.err.(net.Error); ok && ne.Timeout() {
+		var ne net.Error
+		if errors.As(ctx.err, &ne) && ne.Timeout() {
 			// Flush the read data on timeout and try reading again.
 			ctx.err = nil
 		} else {