chore: Fix linter findings for errorlint (part5) (#12731)

Co-authored-by: Pawel Zak <Pawel Zak>

plugins/inputs/fail2ban/fail2ban.go

@@ -50,7 +50,7 @@ func (f *Fail2ban) Init() error {
 	if f.path == "" {
 		path, err := exec.LookPath(cmd)
 		if err != nil {
-			return fmt.Errorf("looking up %q failed: %v", cmd, err)
+			return fmt.Errorf("looking up %q failed: %w", cmd, err)
 		}
 		f.path = path
 	}
@@ -81,7 +81,7 @@ func (f *Fail2ban) Gather(acc telegraf.Accumulator) error {
 	cmd := execCommand(name, args...)
 	out, err := cmd.Output()
 	if err != nil {
-		return fmt.Errorf("failed to run command %s: %s - %s", strings.Join(cmd.Args, " "), err, string(out))
+		return fmt.Errorf("failed to run command %q: %w - %s", strings.Join(cmd.Args, " "), err, string(out))
 	}
 	lines := strings.Split(string(out), "\n")
 	const targetString = "Jail list:"
@@ -102,7 +102,7 @@ func (f *Fail2ban) Gather(acc telegraf.Accumulator) error {
 		cmd := execCommand(name, args...)
 		out, err := cmd.Output()
 		if err != nil {
-			return fmt.Errorf("failed to run command %s: %s - %s", strings.Join(cmd.Args, " "), err, string(out))
+			return fmt.Errorf("failed to run command %q: %w - %s", strings.Join(cmd.Args, " "), err, string(out))
 		}
 
 		lines := strings.Split(string(out), "\n")

plugins/inputs/fireboard/fireboard.go

@@ -96,7 +96,7 @@ func (r *Fireboard) Gather(acc telegraf.Accumulator) error {
 	// Decode the response JSON into a new stats struct
 	var stats []fireboardStats
 	if err := json.NewDecoder(resp.Body).Decode(&stats); err != nil {
-		return fmt.Errorf("unable to decode fireboard response: %s", err)
+		return fmt.Errorf("unable to decode fireboard response: %w", err)
 	}
 	// Range over all devices, gathering stats. Returns early in case of any error.
 	for _, s := range stats {

plugins/inputs/github/github.go

@@ -4,6 +4,7 @@ package github
 import (
 	"context"
 	_ "embed"
+	"errors"
 	"fmt"
 	"net/http"
 	"strings"
@@ -148,10 +149,11 @@ func (g *GitHub) Gather(acc telegraf.Accumulator) error {
 }
 
 func (g *GitHub) handleRateLimit(response *githubLib.Response, err error) {
+	var rlErr *githubLib.RateLimitError
 	if err == nil {
 		g.RateLimit.Set(int64(response.Rate.Limit))
 		g.RateRemaining.Set(int64(response.Rate.Remaining))
-	} else if _, ok := err.(*githubLib.RateLimitError); ok {
+	} else if errors.As(err, &rlErr) {
 		g.RateLimitErrors.Incr(1)
 	}
 }

plugins/inputs/gnmi/gnmi.go

@@ -338,11 +338,11 @@ func (s *Subscription) buildAlias(aliases map[string]string) error {
 
 	longPath, _, err := handlePath(gnmiLongPath, nil, nil, "")
 	if err != nil {
-		return fmt.Errorf("handling long-path failed: %v", err)
+		return fmt.Errorf("handling long-path failed: %w", err)
 	}
 	shortPath, _, err := handlePath(gnmiShortPath, nil, nil, "")
 	if err != nil {
-		return fmt.Errorf("handling short-path failed: %v", err)
+		return fmt.Errorf("handling short-path failed: %w", err)
 	}
 
 	// If the user didn't provide a measurement name, use last path element

plugins/inputs/gnmi/handler.go

@@ -3,6 +3,7 @@ package gnmi
 import (
 	"context"
 	"crypto/tls"
+	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -62,7 +63,7 @@ func (h *handler) subscribeGNMI(ctx context.Context, acc telegraf.Accumulator, t
 
 	client, err := grpc.DialContext(ctx, h.address, opts...)
 	if err != nil {
-		return fmt.Errorf("failed to dial: %v", err)
+		return fmt.Errorf("failed to dial: %w", err)
 	}
 	defer client.Close()
 
@@ -73,7 +74,7 @@ func (h *handler) subscribeGNMI(ctx context.Context, acc telegraf.Accumulator, t
 
 	// If io.EOF is returned, the stream may have ended and stream status
 	// can be determined by calling Recv.
-	if err := subscribeClient.Send(request); err != nil && err != io.EOF {
+	if err := subscribeClient.Send(request); err != nil && !errors.Is(err, io.EOF) {
 		return fmt.Errorf("failed to send subscription request: %w", err)
 	}
 
@@ -82,7 +83,7 @@ func (h *handler) subscribeGNMI(ctx context.Context, acc telegraf.Accumulator, t
 	for ctx.Err() == nil {
 		var reply *gnmiLib.SubscribeResponse
 		if reply, err = subscribeClient.Recv(); err != nil {
-			if err != io.EOF && ctx.Err() == nil {
+			if !errors.Is(err, io.EOF) && ctx.Err() == nil {
 				return fmt.Errorf("aborted gNMI subscription: %w", err)
 			}
 			break

plugins/inputs/gnmi/utils.go

@@ -144,11 +144,11 @@ func gnmiToFields(name string, updateVal *gnmiLib.TypedValue) (map[string]interf
 		fields[name] = value
 	} else if jsondata != nil {
 		if err := json.Unmarshal(jsondata, &value); err != nil {
-			return nil, fmt.Errorf("failed to parse JSON value: %v", err)
+			return nil, fmt.Errorf("failed to parse JSON value: %w", err)
 		}
 		flattener := jsonparser.JSONFlattener{Fields: fields}
 		if err := flattener.FullFlattenJSON(name, value, true, true); err != nil {
-			return nil, fmt.Errorf("failed to flatten JSON: %v", err)
+			return nil, fmt.Errorf("failed to flatten JSON: %w", err)
 		}
 	}
 	return fields, nil

plugins/inputs/google_cloud_storage/google_cloud_storage.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	_ "embed"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -82,7 +83,7 @@ func (gcs *GCS) Gather(acc telegraf.Accumulator) error {
 	for {
 		attrs, err := it.Next()
 
-		if err == iterator.Done {
+		if errors.Is(err, iterator.Done) {
 			gcs.Log.Infof("Iterated all the keys")
 			break
 		}
@@ -96,8 +97,8 @@ func (gcs *GCS) Gather(acc telegraf.Accumulator) error {
 
 		if !gcs.shoudIgnore(name) {
 			if err := gcs.processMeasurementsInObject(name, bucket, acc); err != nil {
-				gcs.Log.Errorf("Could not process object: %v in bucket: %v", name, bucketName, err)
-				acc.AddError(fmt.Errorf("COULD NOT PROCESS OBJECT: %v IN BUCKET: %v", name, err))
+				gcs.Log.Errorf("Could not process object %q in bucket %q: %v", name, bucketName, err)
+				acc.AddError(fmt.Errorf("COULD NOT PROCESS OBJECT %q IN BUCKET %q: %w", name, bucketName, err))
 			}
 		}
 

plugins/inputs/haproxy/haproxy.go

@@ -4,6 +4,7 @@ package haproxy
 import (
 	_ "embed"
 	"encoding/csv"
+	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -85,8 +86,7 @@ func (h *haproxy) Gather(acc telegraf.Accumulator) error {
 }
 
 func (h *haproxy) gatherServerSocket(addr string, acc telegraf.Accumulator) error {
-	var network string
-	var address string
+	var network, address string
 	if strings.HasPrefix(addr, "tcp://") {
 		network = "tcp"
 		address = strings.TrimPrefix(addr, "tcp://")
@@ -96,15 +96,13 @@ func (h *haproxy) gatherServerSocket(addr string, acc telegraf.Accumulator) erro
 	}
 
 	c, err := net.Dial(network, address)
-
 	if err != nil {
-		return fmt.Errorf("could not connect to '%s://%s': %s", network, address, err)
+		return fmt.Errorf("could not connect to '%s://%s': %w", network, address, err)
 	}
 
 	_, errw := c.Write([]byte("show stat\n"))
-
 	if errw != nil {
-		return fmt.Errorf("could not write to socket '%s://%s': %s", network, address, errw)
+		return fmt.Errorf("could not write to socket '%s://%s': %w", network, address, errw)
 	}
 
 	return h.importCsvResult(c, acc, address)
@@ -212,7 +210,7 @@ func (h *haproxy) importCsvResult(r io.Reader, acc telegraf.Accumulator, host st
 
 	for {
 		row, err := csvr.Read()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {

plugins/inputs/http/http.go

@@ -75,7 +75,7 @@ func (h *HTTP) Gather(acc telegraf.Accumulator) error {
 		go func(url string) {
 			defer wg.Done()
 			if err := h.gatherURL(acc, url); err != nil {
-				acc.AddError(fmt.Errorf("[url=%s]: %s", url, err))
+				acc.AddError(fmt.Errorf("[url=%s]: %w", url, err))
 			}
 		}(u)
 	}
@@ -157,17 +157,17 @@ func (h *HTTP) gatherURL(
 
 	b, err := io.ReadAll(resp.Body)
 	if err != nil {
-		return fmt.Errorf("reading body failed: %v", err)
+		return fmt.Errorf("reading body failed: %w", err)
 	}
 
 	// Instantiate a new parser for the new data to avoid trouble with stateful parsers
 	parser, err := h.parserFunc()
 	if err != nil {
-		return fmt.Errorf("instantiating parser failed: %v", err)
+		return fmt.Errorf("instantiating parser failed: %w", err)
 	}
 	metrics, err := parser.Parse(b)
 	if err != nil {
-		return fmt.Errorf("parsing metrics failed: %v", err)
+		return fmt.Errorf("parsing metrics failed: %w", err)
 	}
 
 	for _, metric := range metrics {
@@ -187,13 +187,13 @@ func (h *HTTP) setRequestAuth(request *http.Request) error {
 
 	username, err := h.Username.Get()
 	if err != nil {
-		return fmt.Errorf("getting username failed: %v", err)
+		return fmt.Errorf("getting username failed: %w", err)
 	}
 	defer config.ReleaseSecret(username)
 
 	password, err := h.Password.Get()
 	if err != nil {
-		return fmt.Errorf("getting password failed: %v", err)
+		return fmt.Errorf("getting password failed: %w", err)
 	}
 	defer config.ReleaseSecret(password)
 

plugins/inputs/http_response/http_response.go

@@ -65,9 +65,6 @@ type httpClient interface {
 	Do(req *http.Request) (*http.Response, error)
 }
 
-// ErrRedirectAttempted indicates that a redirect occurred
-var ErrRedirectAttempted = errors.New("redirect")
-
 // Set the proxy. A configured proxy overwrites the system wide proxy.
 func getProxyFunc(httpProxy string) func(*http.Request) (*url.URL, error) {
 	if httpProxy == "" {
@@ -157,27 +154,30 @@ func setResult(resultString string, fields map[string]interface{}, tags map[stri
 }
 
 func setError(err error, fields map[string]interface{}, tags map[string]string) error {
-	if timeoutError, ok := err.(net.Error); ok && timeoutError.Timeout() {
+	var timeoutError net.Error
+	if errors.As(err, &timeoutError) && timeoutError.Timeout() {
 		setResult("timeout", fields, tags)
 		return timeoutError
 	}
 
-	urlErr, isURLErr := err.(*url.Error)
-	if !isURLErr {
+	var urlErr *url.Error
+	if !errors.As(err, &urlErr) {
 		return nil
 	}
 
-	opErr, isNetErr := (urlErr.Err).(*net.OpError)
-	if isNetErr {
-		switch e := (opErr.Err).(type) {
-		case *net.DNSError:
+	var opErr *net.OpError
+	if errors.As(urlErr, &opErr) {
+		var dnsErr *net.DNSError
+		var parseErr *net.ParseError
+
+		if errors.As(opErr, &dnsErr) {
 			setResult("dns_error", fields, tags)
-			return e
-		case *net.ParseError:
+			return dnsErr
+		} else if errors.As(opErr, &parseErr) {
 			// Parse error has to do with parsing of IP addresses, so we
 			// group it with address errors
 			setResult("address_error", fields, tags)
-			return e
+			return parseErr
 		}
 	}
 
@@ -339,7 +339,7 @@ func (h *HTTPResponse) Gather(acc telegraf.Accumulator) error {
 		var err error
 		h.compiledStringMatch, err = regexp.Compile(h.ResponseStringMatch)
 		if err != nil {
-			return fmt.Errorf("failed to compile regular expression %s : %s", h.ResponseStringMatch, err)
+			return fmt.Errorf("failed to compile regular expression %q: %w", h.ResponseStringMatch, err)
 		}
 	}
 
@@ -401,12 +401,12 @@ func (h *HTTPResponse) Gather(acc telegraf.Accumulator) error {
 func (h *HTTPResponse) setRequestAuth(request *http.Request) error {
 	username, err := h.Username.Get()
 	if err != nil {
-		return fmt.Errorf("getting username failed: %v", err)
+		return fmt.Errorf("getting username failed: %w", err)
 	}
 	defer config.ReleaseSecret(username)
 	password, err := h.Password.Get()
 	if err != nil {
-		return fmt.Errorf("getting password failed: %v", err)
+		return fmt.Errorf("getting password failed: %w", err)
 	}
 	defer config.ReleaseSecret(password)
 	if len(username) != 0 || len(password) != 0 {

plugins/inputs/hugepages/hugepages.go

@@ -96,19 +96,19 @@ func (h *Hugepages) Init() error {
 func (h *Hugepages) Gather(acc telegraf.Accumulator) error {
 	if h.gatherRoot {
 		if err := h.gatherRootStats(acc); err != nil {
-			return fmt.Errorf("gathering root stats failed: %v", err)
+			return fmt.Errorf("gathering root stats failed: %w", err)
 		}
 	}
 
 	if h.gatherPerNode {
 		if err := h.gatherStatsPerNode(acc); err != nil {
-			return fmt.Errorf("gathering per node stats failed: %v", err)
+			return fmt.Errorf("gathering per node stats failed: %w", err)
 		}
 	}
 
 	if h.gatherMeminfo {
 		if err := h.gatherStatsFromMeminfo(acc); err != nil {
-			return fmt.Errorf("gathering meminfo stats failed: %v", err)
+			return fmt.Errorf("gathering meminfo stats failed: %w", err)
 		}
 	}
 
@@ -160,7 +160,7 @@ func (h *Hugepages) gatherFromHugepagePath(
 	// read metrics from: hugepages/hugepages-*/*
 	hugepagesDirs, err := os.ReadDir(path)
 	if err != nil {
-		return fmt.Errorf("reading root dir failed: %v", err)
+		return fmt.Errorf("reading root dir failed: %w", err)
 	}
 
 	for _, hugepagesDir := range hugepagesDirs {
@@ -177,7 +177,7 @@ func (h *Hugepages) gatherFromHugepagePath(
 		metricsPath := filepath.Join(path, hugepagesDir.Name())
 		metricFiles, err := os.ReadDir(metricsPath)
 		if err != nil {
-			return fmt.Errorf("reading metric dir failed: %v", err)
+			return fmt.Errorf("reading metric dir failed: %w", err)
 		}
 
 		metrics := make(map[string]interface{})