chore(linters): Enable `string-format` rule for revive (#15983)

.golangci.yml

@@ -290,6 +290,23 @@ linters-settings:
       - name: receiver-naming
       - name: redefines-builtin-id
       - name: redundant-import-alias
+      - name: string-format
+        arguments:
+          - - 'fmt.Errorf[0]'
+            - '/^([^A-Z]|$)/'
+            - 'Error string must not start with a capital letter.'
+          - - 'fmt.Errorf[0]'
+            - '/(^|[^\.!?])$/'
+            - 'Error string must not end in punctuation.'
+          - - 'errors.New[0]'
+            - '/^([^A-Z]|$)/'
+            - 'Error string must not start with a capital letter.'
+          - - 'errors.New[0]'
+            - '/(^|[^\.!?])$/'
+            - 'Error string must not end in punctuation.'
+          - - 'panic'
+            - '/^[^\n]*$/'
+            - 'Must not contain line breaks.'
       - name: string-of-int
       - name: struct-tag
       - name: superfluous-else

cmd/telegraf/telegraf.go

@@ -343,10 +343,10 @@ func (t *Telegraf) runAgent(ctx context.Context, reloadConfig bool) error {
 	}
 
 	if !(t.test || t.testWait != 0) && len(c.Outputs) == 0 {
-		return errors.New("no outputs found, did you provide a valid config file?")
+		return errors.New("no outputs found, probably invalid config file provided")
 	}
 	if t.plugindDir == "" && len(c.Inputs) == 0 {
-		return errors.New("no inputs found, did you provide a valid config file?")
+		return errors.New("no inputs found, probably invalid config file provided")
 	}
 
 	if int64(c.Agent.Interval) <= 0 {

internal/snmp/field.go

@@ -85,11 +85,11 @@ func (f *Field) Init(tr Translator) error {
 	}
 
 	if f.SecondaryIndexTable && f.SecondaryIndexUse {
-		return errors.New("SecondaryIndexTable and UseSecondaryIndex are exclusive")
+		return errors.New("fields SecondaryIndexTable and UseSecondaryIndex are exclusive")
 	}
 
 	if !f.SecondaryIndexTable && !f.SecondaryIndexUse && f.SecondaryOuterJoin {
-		return errors.New("SecondaryOuterJoin set to true, but field is not being used in join")
+		return errors.New("field SecondaryOuterJoin set to true, but field is not being used in join")
 	}
 
 	switch f.Conversion {

internal/snmp/table.go

@@ -51,12 +51,12 @@ type RTableRow struct {
 	Fields map[string]interface{}
 }
 
-// Init() builds & initializes the nested fields.
+// Init builds & initializes the nested fields.
 func (t *Table) Init(tr Translator) error {
 	// makes sure oid or name is set in config file
 	// otherwise snmp will produce metrics with an empty name
 	if t.Oid == "" && t.Name == "" {
-		return errors.New("SNMP table in config file is not named. One or both of the oid and name settings must be set")
+		return errors.New("unnamed SNMP table in config file: one or both of the oid and name settings must be set")
 	}
 
 	if t.initialized {

plugins/common/shim/goshim.go

@@ -79,17 +79,17 @@ func (s *Shim) Run(pollInterval time.Duration) error {
 	if s.Input != nil {
 		err := s.RunInput(pollInterval)
 		if err != nil {
-			return fmt.Errorf("RunInput error: %w", err)
+			return fmt.Errorf("running input failed: %w", err)
 		}
 	} else if s.Processor != nil {
 		err := s.RunProcessor()
 		if err != nil {
-			return fmt.Errorf("RunProcessor error: %w", err)
+			return fmt.Errorf("running processor failed: %w", err)
 		}
 	} else if s.Output != nil {
 		err := s.RunOutput()
 		if err != nil {
-			return fmt.Errorf("RunOutput error: %w", err)
+			return fmt.Errorf("running output failed: %w", err)
 		}
 	} else {
 		return errors.New("nothing to run")

plugins/common/socket/stream.go

@@ -100,7 +100,7 @@ func (l *streamListener) setupVsock(u *url.URL) error {
 
 	// Check address string for containing two tokens
 	if len(addrTuple) < 2 {
-		return errors.New("CID and/or port number missing")
+		return errors.New("port and/or CID number missing")
 	}
 	// Parse CID and port number from address string both being 32-bit
 	// source: https://man7.org/linux/man-pages/man7/vsock.7.html
@@ -109,7 +109,7 @@ func (l *streamListener) setupVsock(u *url.URL) error {
 		return fmt.Errorf("failed to parse CID %s: %w", addrTuple[0], err)
 	}
 	if (cid >= uint64(math.Pow(2, 32))-1) && (cid <= 0) {
-		return fmt.Errorf("CID %d is out of range", cid)
+		return fmt.Errorf("value of CID %d is out of range", cid)
 	}
 	port, err := strconv.ParseUint(addrTuple[1], 10, 32)
 	if err != nil {

plugins/inputs/activemq/activemq.go

@@ -155,7 +155,7 @@ func (a *ActiveMQ) GetMetrics(u string) ([]byte, error) {
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("GET %s returned status %q", u, resp.Status)
+		return nil, fmt.Errorf("%s returned HTTP status %s", u, resp.Status)
 	}
 
 	return io.ReadAll(resp.Body)

plugins/inputs/bond/bond.go

@@ -137,7 +137,7 @@ func (bond *Bond) gatherBondPart(bondName, rawFile string, acc telegraf.Accumula
 	if err := scanner.Err(); err != nil {
 		return err
 	}
-	return fmt.Errorf("Couldn't find status info for %q", bondName)
+	return fmt.Errorf("couldn't find status info for %q", bondName)
 }
 
 func (bond *Bond) readSysFiles(bondDir string) (sysFiles, error) {

plugins/inputs/cisco_telemetry_mdt/cisco_telemetry_mdt.go

@@ -304,7 +304,7 @@ func (c *CiscoTelemetryMDT) handleTCPClient(conn net.Conn) error {
 			if err != nil {
 				return err
 			}
-			return errors.New("TCP dialout premature EOF")
+			return errors.New("premature EOF during TCP dialout")
 		}
 
 		c.handleTelemetry(payload.Bytes())
@@ -324,13 +324,13 @@ func (c *CiscoTelemetryMDT) MdtDialout(stream mdtdialout.GRPCMdtDialout_MdtDialo
 		packet, err := stream.Recv()
 		if err != nil {
 			if !errors.Is(err, io.EOF) {
-				c.acc.AddError(fmt.Errorf("GRPC dialout receive error: %w", err))
+				c.acc.AddError(fmt.Errorf("receive error during GRPC dialout: %w", err))
 			}
 			break
 		}
 
 		if len(packet.Data) == 0 && len(packet.Errors) != 0 {
-			c.acc.AddError(fmt.Errorf("GRPC dialout error: %s", packet.Errors))
+			c.acc.AddError(fmt.Errorf("error during GRPC dialout: %s", packet.Errors))
 			break
 		}
 
@@ -763,7 +763,7 @@ func (c *CiscoTelemetryMDT) parseContentField(
 	if len(rn) > 0 {
 		tags[prefix] = rn
 	} else if !dn { // Check for distinguished name being present
-		c.acc.AddError(errors.New("NX-OS decoding failed: missing dn field"))
+		c.acc.AddError(errors.New("failed while decoding NX-OS: missing 'dn' field"))
 		return
 	}
 

plugins/inputs/cisco_telemetry_mdt/cisco_telemetry_mdt_test.go

@@ -1201,7 +1201,7 @@ func TestGRPCDialoutError(t *testing.T) {
 	require.True(t, err == nil || errors.Is(err, io.EOF))
 	c.Stop()
 
-	require.Equal(t, []error{errors.New("GRPC dialout error: foobar")}, acc.Errors)
+	require.Equal(t, []error{errors.New("error during GRPC dialout: foobar")}, acc.Errors)
 }
 
 func TestGRPCDialoutMultiple(t *testing.T) {
@@ -1262,7 +1262,7 @@ func TestGRPCDialoutMultiple(t *testing.T) {
 	c.Stop()
 	require.NoError(t, conn.Close())
 
-	require.Equal(t, []error{errors.New("GRPC dialout error: testclose"), errors.New("GRPC dialout error: testclose")}, acc.Errors)
+	require.Equal(t, []error{errors.New("error during GRPC dialout: testclose"), errors.New("error during GRPC dialout: testclose")}, acc.Errors)
 
 	tags := map[string]string{
 		"path":         "type:model/some/path",

plugins/inputs/google_cloud_storage/google_cloud_storage.go

@@ -97,7 +97,7 @@ func (gcs *GCS) Gather(acc telegraf.Accumulator) error {
 		if !gcs.shouldIgnore(name) {
 			if err := gcs.processMeasurementsInObject(name, bucket, acc); err != nil {
 				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))
+				acc.AddError(fmt.Errorf("could not process object %q in bucket %q: %w", name, bucketName, err))
 			}
 		}
 
@@ -238,7 +238,7 @@ func (gcs *GCS) setUpDefaultClient() error {
 
 func (gcs *GCS) setOffset() error {
 	if gcs.client == nil {
-		return errors.New("CANNOT SET OFFSET IF CLIENT IS NOT SET")
+		return errors.New("cannot set offset if client is not set")
 	}
 
 	if gcs.OffsetKey != "" {

plugins/inputs/influxdb_listener/influxdb_listener.go

@@ -9,6 +9,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"net/http"
 	"time"
@@ -449,7 +450,7 @@ func (h *InfluxDBListener) handleWriteUpstreamParser(res http.ResponseWriter, re
 
 		h.acc.AddMetric(m)
 	}
-	if !errors.Is(err, influx_upstream.ErrEOF) {
+	if !errors.Is(err, io.EOF) {
 		h.Log.Debugf("Error parsing the request body: %v", err.Error())
 		if err := badRequest(res, err.Error()); err != nil {
 			h.Log.Debugf("error in bad-request: %v", err)

plugins/inputs/influxdb_v2_listener/influxdb_v2_listener.go

@@ -38,8 +38,6 @@ const (
 	defaultWriteTimeout = 10 * time.Second
 )
 
-var ErrEOF = errors.New("EOF")
-
 // The BadRequestCode constants keep standard error messages
 // see: https://v2.docs.influxdata.com/v2.0/api/#operation/PostWrite
 type BadRequestCode string
@@ -309,7 +307,7 @@ func (h *InfluxDBV2Listener) handleWrite() http.HandlerFunc {
 		if h.ParserType == "upstream" {
 			parser := influx_upstream.Parser{}
 			err = parser.Init()
-			if !errors.Is(err, ErrEOF) && err != nil {
+			if !errors.Is(err, io.EOF) && err != nil {
 				h.Log.Debugf("Error initializing parser: %v", err.Error())
 				return
 			}
@@ -327,7 +325,7 @@ func (h *InfluxDBV2Listener) handleWrite() http.HandlerFunc {
 		} else {
 			parser := influx.Parser{}
 			err = parser.Init()
-			if !errors.Is(err, ErrEOF) && err != nil {
+			if !errors.Is(err, io.EOF) && err != nil {
 				h.Log.Debugf("Error initializing parser: %v", err.Error())
 				return
 			}
@@ -341,7 +339,7 @@ func (h *InfluxDBV2Listener) handleWrite() http.HandlerFunc {
 			metrics, err = parser.Parse(bytes)
 		}
 
-		if !errors.Is(err, ErrEOF) && err != nil {
+		if !errors.Is(err, io.EOF) && err != nil {
 			h.Log.Debugf("Error parsing the request body: %v", err.Error())
 			if err := badRequest(res, Invalid, err.Error()); err != nil {
 				h.Log.Debugf("error in bad-request: %v", err)

plugins/inputs/intel_pmt/xml_parser.go

@@ -176,11 +176,8 @@ func (p *IntelPMT) readXMLs() error {
 			p.Log.Warnf("Configured sample metric %q has not been found", sm)
 		}
 	}
-	err := p.verifyNoEmpty()
+
-	if err != nil {
+	return p.verifyNoEmpty()
-		return fmt.Errorf("XMLs empty: %w", err)
-	}
-	return nil
 }
 
 // getAllXMLData retrieves two XMLs for given GUID.
@@ -254,7 +251,7 @@ func computeMask(msb, lsb uint64) uint64 {
 
 func parseXML(source string, sr sourceReader, v interface{}) error {
 	if sr == nil {
-		return errors.New("XML reader failed to initialize")
+		return errors.New("xml reader has not been initialized")
 	}
 	reader, err := sr.getReadCloser(source)
 	if err != nil {

plugins/inputs/iptables/iptables.go

@@ -82,10 +82,12 @@ func (ipt *Iptables) chainList(table, chain string) (string, error) {
 
 const measurement = "iptables"
 
-var errParse = errors.New("Cannot parse iptables list information")
+var (
-var chainNameRe = regexp.MustCompile(`^Chain\s+(\S+)`)
+	errParse       = errors.New("cannot parse iptables list information")
-var fieldsHeaderRe = regexp.MustCompile(`^\s*pkts\s+bytes\s+target`)
+	chainNameRe    = regexp.MustCompile(`^Chain\s+(\S+)`)
-var valuesRe = regexp.MustCompile(`^\s*(\d+)\s+(\d+)\s+(\w+).*?/\*\s*(.+?)\s*\*/\s*`)
+	fieldsHeaderRe = regexp.MustCompile(`^\s*pkts\s+bytes\s+target`)
+	valuesRe       = regexp.MustCompile(`^\s*(\d+)\s+(\d+)\s+(\w+).*?/\*\s*(.+?)\s*\*/\s*`)
+)
 
 func (ipt *Iptables) parseAndGather(data string, acc telegraf.Accumulator) error {
 	lines := strings.Split(data, "\n")

plugins/inputs/kafka_consumer/kafka_consumer.go

@@ -132,7 +132,7 @@ func (k *KafkaConsumer) Init() error {
 	}
 
 	if err := k.SetConfig(cfg, k.Log); err != nil {
-		return fmt.Errorf("SetConfig: %w", err)
+		return fmt.Errorf("setting config failed: %w", err)
 	}
 
 	switch strings.ToLower(k.Offset) {

plugins/inputs/linux_cpu/linux_cpu.go

@@ -182,11 +182,9 @@ func init() {
 
 func validatePath(propPath string) error {
 	f, err := os.Open(propPath)
-
 	if os.IsNotExist(err) {
-		return fmt.Errorf("CPU property does not exist: [%s]", propPath)
+		return fmt.Errorf("file with CPU property does not exist: %q", propPath)
 	}
-
 	if err != nil {
 		return fmt.Errorf("cannot get system information for CPU property %q: %w", propPath, err)
 	}

plugins/inputs/nginx_plus_api/nginx_plus_api.go

@@ -74,7 +74,7 @@ func (n *NginxPlusAPI) Gather(acc telegraf.Accumulator) error {
 	for _, u := range n.Urls {
 		addr, err := url.Parse(u)
 		if err != nil {
-			acc.AddError(fmt.Errorf("Unable to parse address %q: %w", u, err))
+			acc.AddError(fmt.Errorf("unable to parse address %q: %w", u, err))
 			continue
 		}
 

plugins/inputs/opcua/read_client.go

@@ -139,7 +139,7 @@ func (o *ReadClient) read() error {
 	resp, err := o.Client.Read(o.ctx, req)
 	if err != nil {
 		o.ReadError.Incr(1)
-		return fmt.Errorf("RegisterNodes Read failed: %w", err)
+		return fmt.Errorf("reading registered nodes failed: %w", err)
 	}
 	o.ReadSuccess.Incr(1)
 	for i, d := range resp.Results {

plugins/inputs/ping/ping_windows_test.go

@@ -104,7 +104,7 @@ Statystyka badania ping dla 195.187.242.157:
 `
 
 func mockErrorHostPinger(string, float64, ...string) (string, error) {
-	return errorPingOutput, errors.New("No packets received")
+	return errorPingOutput, errors.New("no packets received")
 }
 
 // Test that Gather works on a ping with no transmitted packets, even though the
@@ -228,7 +228,7 @@ Options:
 `
 
 func mockFatalHostPinger(string, float64, ...string) (string, error) {
-	return fatalPingOutput, errors.New("So very bad")
+	return fatalPingOutput, errors.New("so very bad")
 }
 
 // Test that a fatal ping command does not gather any statistics.
@@ -273,7 +273,7 @@ Ping statistics for 8.8.8.8:
 `
 
 func mockUnreachableHostPinger(string, float64, ...string) (string, error) {
-	return UnreachablePingOutput, errors.New("So very bad")
+	return UnreachablePingOutput, errors.New("so very bad")
 }
 
 // Reply from 185.28.251.217: TTL expired in transit.
@@ -324,7 +324,7 @@ Ping statistics for 8.8.8.8:
 `
 
 func mockTTLExpiredPinger(string, float64, ...string) (string, error) {
-	return TTLExpiredPingOutput, errors.New("So very bad")
+	return TTLExpiredPingOutput, errors.New("so very bad")
 }
 
 // in case 'Destination net unreachable' ping app return receive packet which is not what we need

plugins/inputs/sflow/packetdecoder.go

@@ -60,7 +60,7 @@ func (d *packetDecoder) DecodeOnePacket(r io.Reader) (*v5Format, error) {
 		return nil, err
 	}
 	if p.Version != 5 {
-		return nil, fmt.Errorf("Version %d not supported, only version 5", p.Version)
+		return nil, fmt.Errorf("version %d not supported, only version 5", p.Version)
 	}
 	var addressIPType AddressType
 	if err := read(r, &addressIPType, "address ip type"); err != nil {
@@ -74,7 +74,7 @@ func (d *packetDecoder) DecodeOnePacket(r io.Reader) (*v5Format, error) {
 	case AddressTypeIPV6:
 		p.AgentAddress.IP = make([]byte, 16)
 	default:
-		return nil, fmt.Errorf("Unknown address IP type %d", addressIPType)
+		return nil, fmt.Errorf("unknown address IP type %d", addressIPType)
 	}
 	if err := read(r, &p.AgentAddress.IP, "Agent Address IP"); err != nil {
 		return nil, err
@@ -389,7 +389,7 @@ func (d *packetDecoder) decodeIPv6Header(r io.Reader) (h ipV6Header, err error)
 	}
 	version := fourByteBlock >> 28
 	if version != 0x6 {
-		return h, fmt.Errorf("Unexpected IPv6 header version 0x%x", version)
+		return h, fmt.Errorf("unexpected IPv6 header version 0x%x", version)
 	}
 	h.DSCP = uint8((fourByteBlock & 0xFC00000) >> 22)
 	h.ECN = uint8((fourByteBlock & 0x300000) >> 20)

plugins/inputs/smartctl/smartctl.go

@@ -70,12 +70,12 @@ func (s *Smartctl) Init() error {
 func (s *Smartctl) Gather(acc telegraf.Accumulator) error {
 	devices, err := s.scan()
 	if err != nil {
-		return fmt.Errorf("Error scanning system: %w", err)
+		return fmt.Errorf("error while scanning system: %w", err)
 	}
 
 	for _, device := range devices {
 		if err := s.scanDevice(acc, device.Name, device.Type); err != nil {
-			return fmt.Errorf("Error getting device %s: %w", device, err)
+			return fmt.Errorf("error while getting device %s: %w", device, err)
 		}
 	}
 

plugins/inputs/supervisor/supervisor.go

@@ -144,7 +144,7 @@ func (s *Supervisor) Init() error {
 	// Initializing XML-RPC client
 	s.rpcClient, err = xmlrpc.NewClient(s.Server, nil)
 	if err != nil {
-		return fmt.Errorf("XML-RPC client initialization failed: %w", err)
+		return fmt.Errorf("failed to initialize XML-RPC client: %w", err)
 	}
 	// Setting filter for additional metrics
 	s.fieldFilter, err = filter.NewIncludeExcludeFilter(s.MetricsInc, s.MetricsExc)

plugins/inputs/systemd_units/systemd_units_test.go

@@ -969,7 +969,7 @@ func (c *fakeClient) GetUnitTypePropertiesContext(_ context.Context, unit, unitT
 		return nil, nil
 	}
 	if u.utype != unitType {
-		return nil, fmt.Errorf("Unknown interface 'org.freedesktop.systemd1.%s", unitType)
+		return nil, fmt.Errorf("unknown interface 'org.freedesktop.systemd1.%s", unitType)
 	}
 	return u.properties, nil
 }

plugins/inputs/tengine/tengine.go

@@ -52,7 +52,7 @@ func (n *Tengine) Gather(acc telegraf.Accumulator) error {
 	for _, u := range n.Urls {
 		addr, err := url.Parse(u)
 		if err != nil {
-			acc.AddError(fmt.Errorf("Unable to parse address %q: %w", u, err))
+			acc.AddError(fmt.Errorf("unable to parse address %q: %w", u, err))
 			continue
 		}
 

plugins/inputs/unbound/unbound.go

@@ -133,8 +133,7 @@ func (s *Unbound) Gather(acc telegraf.Accumulator) error {
 
 		fieldValue, err := strconv.ParseFloat(value, 64)
 		if err != nil {
-			acc.AddError(fmt.Errorf("Expected a numerical value for %s = %v",
+			acc.AddError(fmt.Errorf("expected a numerical value for %s = %v", stat, value))
-				stat, value))
 			continue
 		}
 

plugins/inputs/zipkin/codec/jsonV1/jsonV1.go

@@ -220,7 +220,7 @@ func TraceIDFromString(s string) (string, error) {
 	var hi, lo uint64
 	var err error
 	if len(s) > 32 {
-		return "", fmt.Errorf("TraceID cannot be longer than 32 hex characters: %s", s)
+		return "", fmt.Errorf("length of TraceID cannot be greater than 32 hex characters: %s", s)
 	} else if len(s) > 16 {
 		hiLen := len(s) - 16
 		if hi, err = strconv.ParseUint(s[0:hiLen], 16, 64); err != nil {
@@ -243,7 +243,7 @@ func TraceIDFromString(s string) (string, error) {
 // IDFromString validates the ID and returns it in hexadecimal format.
 func IDFromString(s string) (string, error) {
 	if len(s) > 16 {
-		return "", fmt.Errorf("ID cannot be longer than 16 hex characters: %s", s)
+		return "", fmt.Errorf("length of ID cannot be greater than 16 hex characters: %s", s)
 	}
 	id, err := strconv.ParseUint(s, 16, 64)
 	if err != nil {

plugins/inputs/zipkin/handler.go

@@ -118,7 +118,7 @@ func (s *SpanHandler) Spans(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusNoContent)
 }
 
-// ContentDecoer returns a Decoder that is able to produce Traces from bytes.
+// ContentDecoder returns a Decoder that is able to produce Traces from bytes.
 // Failure should yield an HTTP 415 (`http.StatusUnsupportedMediaType`)
 // If a Content-Type is not set, zipkin assumes application/json
 func ContentDecoder(r *http.Request) (codec.Decoder, error) {
@@ -138,5 +138,5 @@ func ContentDecoder(r *http.Request) (codec.Decoder, error) {
 			return &thrift.Thrift{}, nil
 		}
 	}
-	return nil, fmt.Errorf("Unknown Content-Type: %s", contentType)
+	return nil, fmt.Errorf("unknown Content-Type: %s", contentType)
 }

plugins/inputs/zipkin/zipkin_test.go

@@ -2,7 +2,6 @@ package zipkin
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"net/http"
 	"os"
@@ -646,18 +645,18 @@ func postThriftData(datafile, address, contentType string) error {
 		return fmt.Errorf("could not read from data file %s", datafile)
 	}
 
-	req, err := http.NewRequest("POST", fmt.Sprintf("http://%s/api/v1/spans", address), bytes.NewReader(dat))
+	endpoint := fmt.Sprintf("http://%s/api/v1/spans", address)
+	req, err := http.NewRequest("POST", endpoint, bytes.NewReader(dat))
 	if err != nil {
-		return errors.New("HTTP request creation failed")
+		return fmt.Errorf("unable to create new POST request for %q: %w", endpoint, err)
 	}
 
 	req.Header.Set("Content-Type", contentType)
 	client := &http.Client{}
 	resp, err := client.Do(req)
 	if err != nil {
-		return fmt.Errorf("HTTP POST request to zipkin endpoint %q failed: %w", address, err)
+		return fmt.Errorf("error while making HTTP POST request to zipkin endpoint %q: %w", endpoint, err)
 	}
-
 	defer resp.Body.Close()
 
 	return nil

plugins/outputs/mongodb/mongodb.go

@@ -97,10 +97,10 @@ func (s *MongoDB) Init() error {
 	switch s.AuthenticationType {
 	case "SCRAM":
 		if s.Username.Empty() {
-			return errors.New("SCRAM authentication must specify a username")
+			return errors.New("authentication for SCRAM must specify a username")
 		}
 		if s.Password.Empty() {
-			return errors.New("SCRAM authentication must specify a password")
+			return errors.New("authentication for SCRAM must specify a password")
 		}
 		username, err := s.Username.Get()
 		if err != nil {

plugins/outputs/nats/nats.go

@@ -268,7 +268,7 @@ func (n *NATS) Write(metrics []telegraf.Metric) error {
 		// use the same Publish API for nats core and jetstream
 		err = n.conn.Publish(n.Subject, buf)
 		if err != nil {
-			return fmt.Errorf("FAILED to send NATS message: %w", err)
+			return fmt.Errorf("failed to send NATS message: %w", err)
 		}
 	}
 	return nil

plugins/outputs/newrelic/newrelic.go

@@ -43,7 +43,7 @@ func (*NewRelic) SampleConfig() string {
 // Connect to the Output
 func (nr *NewRelic) Connect() error {
 	if nr.InsightsKey == "" {
-		return errors.New("InsightKey is a required for newrelic")
+		return errors.New("'insights_key' is a required for newrelic")
 	}
 	err := nr.initClient()
 	if err != nil {

plugins/outputs/opentsdb/opentsdb.go

@@ -74,11 +74,11 @@ func (o *OpenTSDB) Connect() error {
 	uri := fmt.Sprintf("%s:%d", u.Host, o.Port)
 	tcpAddr, err := net.ResolveTCPAddr("tcp", uri)
 	if err != nil {
-		return fmt.Errorf("OpenTSDB TCP address cannot be resolved: %w", err)
+		return fmt.Errorf("failed to resolve TCP address: %w", err)
 	}
 	connection, err := net.DialTCP("tcp", nil, tcpAddr)
 	if err != nil {
-		return fmt.Errorf("OpenTSDB Telnet connect fail: %w", err)
+		return fmt.Errorf("failed to connect to OpenTSDB: %w", err)
 	}
 	defer connection.Close()
 	return nil
@@ -154,11 +154,11 @@ func (o *OpenTSDB) WriteTelnet(metrics []telegraf.Metric, u *url.URL) error {
 	uri := fmt.Sprintf("%s:%d", u.Host, o.Port)
 	tcpAddr, err := net.ResolveTCPAddr("tcp", uri)
 	if err != nil {
-		return fmt.Errorf("OpenTSDB: Telnet connect fail: %w", err)
+		return fmt.Errorf("failed to resolve TCP address: %w", err)
 	}
 	connection, err := net.DialTCP("tcp", nil, tcpAddr)
 	if err != nil {
-		return errors.New("OpenTSDB: Telnet connect fail")
+		return fmt.Errorf("failed to connect to OpenTSDB: %w", err)
 	}
 	defer connection.Close()
 

plugins/outputs/socket_writer/socket_writer.go

@@ -65,7 +65,7 @@ func (sw *SocketWriter) Connect() error {
 
 		// Check address string for containing two
 		if len(addrTuple) < 2 {
-			return errors.New("CID and/or port number missing")
+			return errors.New("port and/or CID number missing")
 		}
 
 		// Parse CID and port number from address string both being 32-bit
@@ -75,7 +75,7 @@ func (sw *SocketWriter) Connect() error {
 			return fmt.Errorf("failed to parse CID %s: %w", addrTuple[0], err)
 		}
 		if (cid >= uint64(math.Pow(2, 32))-1) && (cid <= 0) {
-			return fmt.Errorf("CID %d is out of range", cid)
+			return fmt.Errorf("value of CID %d is out of range", cid)
 		}
 		port, err := strconv.ParseUint(addrTuple[1], 10, 32)
 		if err != nil {

plugins/outputs/stackdriver/stackdriver_test.go

@@ -62,7 +62,7 @@ func (s *mockMetricServer) CreateTimeSeries(ctx context.Context, req *monitoring
 	if s.err != nil {
 		var statusResp *status.Status
 		switch s.err.Error() {
-		case "InvalidArgument":
+		case "invalid argument":
 			statusResp = status.New(codes.InvalidArgument, s.err.Error())
 		default:
 			statusResp = status.New(codes.Unknown, s.err.Error())
@@ -616,12 +616,12 @@ func TestWriteIgnoredErrors(t *testing.T) {
 	}{
 		{
 			name:        "other errors reported",
-			err:         errors.New("Unknown"),
+			err:         errors.New("unknown"),
 			expectedErr: true,
 		},
 		{
 			name:        "invalid argument",
-			err:         errors.New("InvalidArgument"),
+			err:         errors.New("invalid argument"),
 			expectedErr: false,
 		},
 	}

plugins/outputs/timestream/timestream.go

@@ -114,11 +114,11 @@ func (*Timestream) SampleConfig() string {
 
 func (t *Timestream) Connect() error {
 	if t.DatabaseName == "" {
-		return errors.New("DatabaseName key is required")
+		return errors.New("'database_name' key is required")
 	}
 
 	if t.MappingMode == "" {
-		return errors.New("MappingMode key is required")
+		return errors.New("'mapping_mode' key is required")
 	}
 
 	if t.MappingMode != MappingModeSingleTable && t.MappingMode != MappingModeMultiTable {

plugins/outputs/timestream/timestream_test.go

@@ -74,13 +74,13 @@ func TestConnectValidatesConfigParameters(t *testing.T) {
 	}
 	// checking base arguments
 	noDatabaseName := Timestream{Log: testutil.Logger{}}
-	require.Contains(t, noDatabaseName.Connect().Error(), "DatabaseName")
+	require.ErrorContains(t, noDatabaseName.Connect(), "'database_name' key is required")
 
 	noMappingMode := Timestream{
 		DatabaseName: tsDbName,
 		Log:          testutil.Logger{},
 	}
-	require.Contains(t, noMappingMode.Connect().Error(), "MappingMode")
+	require.ErrorContains(t, noMappingMode.Connect(), "'mapping_mode' key is required")
 
 	incorrectMappingMode := Timestream{
 		DatabaseName: tsDbName,

plugins/parsers/dropwizard/parser.go

@@ -2,6 +2,7 @@ package dropwizard
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"time"
 
@@ -97,8 +98,8 @@ func (p *Parser) Parse(buf []byte) ([]telegraf.Metric, error) {
 }
 
 // ParseLine is not supported by the dropwizard format
-func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
+func (p *Parser) ParseLine(_ string) (telegraf.Metric, error) {
-	return nil, fmt.Errorf("ParseLine not supported: %s, for data format: dropwizard", line)
+	return nil, errors.New("parsing line is not supported by the dropwizard format")
 }
 
 // SetDefaultTags sets the default tags

plugins/parsers/influx/influx_upstream/parser.go

@@ -21,7 +21,6 @@ const (
 
 var (
 	ErrNoMetric = errors.New("no metric in line")
-	ErrEOF      = errors.New("EOF")
 )
 
 type TimeFunc func() time.Time
@@ -259,7 +258,7 @@ func (sp *StreamParser) Next() (telegraf.Metric, error) {
 			return nil, err
 		}
 
-		return nil, ErrEOF
+		return nil, io.EOF
 	}
 
 	m, err := nextMetric(sp.decoder, sp.precision, sp.defaultTime, false)

plugins/parsers/influx/influx_upstream/parser_test.go

@@ -660,7 +660,7 @@ func TestStreamParser(t *testing.T) {
 			for {
 				m, err := parser.Next()
 				if err != nil {
-					if errors.Is(err, ErrEOF) {
+					if errors.Is(err, io.EOF) {
 						break
 					}
 					require.Equal(t, tt.err.Error(), err.Error())
@@ -958,7 +958,7 @@ func TestStreamParserErrorString(t *testing.T) {
 			var errs []error
 			for i := 0; i < 20; i++ {
 				_, err := parser.Next()
-				if errors.Is(err, ErrEOF) {
+				if errors.Is(err, io.EOF) {
 					break
 				}
 
@@ -997,7 +997,7 @@ func TestStreamParserReaderError(t *testing.T) {
 	require.Equal(t, err, readerErr)
 
 	_, err = parser.Next()
-	require.Equal(t, err, ErrEOF)
+	require.Equal(t, err, io.EOF)
 }
 
 func TestStreamParserProducesAllAvailableMetrics(t *testing.T) {

plugins/parsers/json/json_flattener.go

@@ -64,8 +64,7 @@ func (f *JSONFlattener) FullFlattenJSON(fieldName string, v interface{}, convert
 	case nil:
 		return nil
 	default:
-		return fmt.Errorf("JSON Flattener: got unexpected type %T with value %v (%s)",
+		return fmt.Errorf("json flattener: got unexpected type %T with value %v (%s)", t, t, fieldName)
-			t, t, fieldName)
 	}
 	return nil
 }

plugins/parsers/json/parser.go

@@ -92,7 +92,7 @@ func (p *Parser) parseObject(data map[string]interface{}, timestamp time.Time) (
 		}
 
 		if f.Fields[p.TimeKey] == nil {
-			err := errors.New("JSON time key could not be found")
+			err := errors.New("'json_time_key' could not be found")
 			return nil, err
 		}
 

plugins/parsers/json/parser_test.go

@@ -840,7 +840,7 @@ func TestTimeErrors(t *testing.T) {
 	actual, err = parser.Parse([]byte(testString2))
 	require.Error(t, err)
 	require.Empty(t, actual)
-	require.Equal(t, errors.New("JSON time key could not be found"), err)
+	require.Equal(t, errors.New("'json_time_key' could not be found"), err)
 }
 
 func TestShareTimestamp(t *testing.T) {

plugins/parsers/json_v2/parser.go

@@ -230,7 +230,7 @@ func (p *Parser) processMetric(input []byte, data []DataSet, tag bool, timestamp
 	metrics := make([][]telegraf.Metric, 0, len(data))
 	for _, c := range data {
 		if c.Path == "" {
-			return nil, errors.New("GJSON path is required")
+			return nil, errors.New("the GJSON path is required")
 		}
 		result := gjson.GetBytes(input, c.Path)
 		if err := p.checkResult(result, c.Path); err != nil {
@@ -477,7 +477,7 @@ func (p *Parser) processObjects(input []byte, objects []Object, timestamp time.T
 		p.objectConfig = c
 
 		if c.Path == "" {
-			return nil, errors.New("GJSON path is required")
+			return nil, errors.New("the GJSON path is required")
 		}
 
 		result := gjson.GetBytes(input, c.Path)
@@ -649,7 +649,7 @@ func (p *Parser) isExcluded(key string) bool {
 }
 
 func (p *Parser) ParseLine(_ string) (telegraf.Metric, error) {
-	return nil, errors.New("ParseLine is designed for parsing influx line protocol, therefore not implemented for parsing JSON")
+	return nil, errors.New("parsing line is not supported by JSON format")
 }
 
 func (p *Parser) SetDefaultTags(tags map[string]string) {

plugins/parsers/nagios/parser_test.go

@@ -30,10 +30,10 @@ func TestGetExitCode(t *testing.T) {
 		{
 			name: "unexpected error type",
 			errF: func() error {
-				return errors.New("I am not *exec.ExitError")
+				return errors.New("not *exec.ExitError")
 			},
 			expCode: 3,
-			expErr:  errors.New("I am not *exec.ExitError"),
+			expErr:  errors.New("not *exec.ExitError"),
 		},
 	}
 

plugins/parsers/wavefront/element.go

@@ -3,12 +3,12 @@ package wavefront
 import (
 	"errors"
 	"fmt"
+	"io"
 	"strconv"
 	"time"
 )
 
 var (
-	errEOF              = errors.New("EOF")
 	errInvalidTimestamp = errors.New("invalid timestamp")
 )
 
@@ -130,7 +130,7 @@ func (ep *loopedParser) parse(p *PointParser, pt *Point) error {
 			return err
 		}
 		err = ep.wsParser.parse(p, pt)
-		if errors.Is(err, errEOF) {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 	}
@@ -170,7 +170,7 @@ func (ep *whiteSpaceParser) parse(p *PointParser, _ *Point) error {
 
 	if tok == EOF {
 		if !ep.nextOptional {
-			return errEOF
+			return io.EOF
 		}
 		return nil
 	}

plugins/processors/snmp_lookup/lookup_test.go

@@ -27,13 +27,13 @@ func (tsc *testSNMPConnection) Host() string {
 }
 
 func (tsc *testSNMPConnection) Get(_ []string) (*gosnmp.SnmpPacket, error) {
-	return &gosnmp.SnmpPacket{}, errors.New("Not implemented")
+	return &gosnmp.SnmpPacket{}, errors.New("not implemented")
 }
 
 func (tsc *testSNMPConnection) Walk(oid string, wf gosnmp.WalkFunc) error {
 	tsc.calls.Add(1)
 	if len(tsc.values) == 0 {
-		return errors.New("No values")
+		return errors.New("no values")
 	}
 	for void, v := range tsc.values {
 		if void == oid || (len(void) > len(oid) && void[:len(oid)+1] == oid+".") {
@@ -49,7 +49,7 @@ func (tsc *testSNMPConnection) Walk(oid string, wf gosnmp.WalkFunc) error {
 }
 
 func (tsc *testSNMPConnection) Reconnect() error {
-	return errors.New("Not implemented")
+	return errors.New("not implemented")
 }
 
 func TestRegistry(t *testing.T) {
@@ -242,7 +242,7 @@ func TestUpdateAgent(t *testing.T) {
 
 	t.Run("connection fail", func(t *testing.T) {
 		p.getConnectionFunc = func(string) (snmp.Connection, error) {
-			return nil, errors.New("Random connection error")
+			return nil, errors.New("random connection error")
 		}
 
 		start := time.Now()

tools/config_includer/generator.go

@@ -28,7 +28,7 @@ func absolutePath(root, fn string) (string, error) {
 	}
 	pwd, err = filepath.Rel(root, filepath.Dir(pwd))
 	if err != nil {
-		return "", fmt.Errorf("Cannot determine location of %q relative to %q: %w", pwd, root, err)
+		return "", fmt.Errorf("cannot determine location of %q relative to %q: %w", pwd, root, err)
 	}
 	return string(filepath.Separator) + pwd, nil
 }