Fix backend linter errors

pkg/datasource/functions.go

@@ -145,6 +145,10 @@ func applyFunctionsPre(query *QueryModel, items []*zabbix.Item) error {
 
 func applyGroupBy(series timeseries.TimeSeries, params ...interface{}) (timeseries.TimeSeries, error) {
 	pInterval, err := MustString(params[0])
+	if err != nil {
+		return nil, errParsingFunctionParam(err)
+	}
+
 	pAgg, err := MustString(params[1])
 	if err != nil {
 		return nil, errParsingFunctionParam(err)
@@ -169,6 +173,10 @@ func applyGroupBy(series timeseries.TimeSeries, params ...interface{}) (timeseri
 
 func applyPercentile(series timeseries.TimeSeries, params ...interface{}) (timeseries.TimeSeries, error) {
 	pInterval, err := MustString(params[0])
+	if err != nil {
+		return nil, errParsingFunctionParam(err)
+	}
+
 	percentile, err := MustFloat64(params[1])
 	if err != nil {
 		return nil, errParsingFunctionParam(err)
@@ -275,6 +283,10 @@ func applyExponentialMovingAverage(series timeseries.TimeSeries, params ...inter
 
 func applyAggregateBy(series []*timeseries.TimeSeriesData, params ...interface{}) ([]*timeseries.TimeSeriesData, error) {
 	pInterval, err := MustString(params[0])
+	if err != nil {
+		return nil, errParsingFunctionParam(err)
+	}
+
 	pAgg, err := MustString(params[1])
 	if err != nil {
 		return nil, errParsingFunctionParam(err)
@@ -303,6 +315,10 @@ func applySumSeries(series []*timeseries.TimeSeriesData, params ...interface{})
 
 func applyPercentileAgg(series []*timeseries.TimeSeriesData, params ...interface{}) ([]*timeseries.TimeSeriesData, error) {
 	pInterval, err := MustString(params[0])
+	if err != nil {
+		return nil, errParsingFunctionParam(err)
+	}
+
 	percentile, err := MustFloat64(params[1])
 	if err != nil {
 		return nil, errParsingFunctionParam(err)
@@ -331,6 +347,10 @@ func applyPercentileAgg(series []*timeseries.TimeSeriesData, params ...interface
 
 func applyTop(series []*timeseries.TimeSeriesData, params ...interface{}) ([]*timeseries.TimeSeriesData, error) {
 	n, err := MustFloat64(params[0])
+	if err != nil {
+		return nil, errParsingFunctionParam(err)
+	}
+
 	pAgg, err := MustString(params[1])
 	if err != nil {
 		return nil, errParsingFunctionParam(err)
@@ -343,6 +363,10 @@ func applyTop(series []*timeseries.TimeSeriesData, params ...interface{}) ([]*ti
 
 func applyBottom(series []*timeseries.TimeSeriesData, params ...interface{}) ([]*timeseries.TimeSeriesData, error) {
 	n, err := MustFloat64(params[0])
+	if err != nil {
+		return nil, errParsingFunctionParam(err)
+	}
+
 	pAgg, err := MustString(params[1])
 	if err != nil {
 		return nil, errParsingFunctionParam(err)
@@ -413,7 +437,7 @@ func applyTimeShiftPost(series timeseries.TimeSeries, params ...interface{}) (ti
 	if interval == 0 {
 		return series, nil
 	}
-	if shiftForward == true {
+	if shiftForward {
 		interval = -interval
 	}
 

pkg/datasource/resource_handler.go

@@ -2,11 +2,13 @@ package datasource
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"time"
 
 	"github.com/alexanderzobnin/grafana-zabbix/pkg/zabbix"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/resource/httpadapter"
 )
 
@@ -17,7 +19,11 @@ import (
 func (ds *ZabbixDatasource) RootHandler(rw http.ResponseWriter, req *http.Request) {
 	ds.logger.Debug("Received resource call", "url", req.URL.String(), "method", req.Method)
 
-	rw.Write([]byte("Hello from Zabbix data source!"))
+	_, err := rw.Write([]byte("Hello from Zabbix data source!"))
+	if err != nil {
+		ds.logger.Warn("Error writing response")
+	}
+
 	rw.WriteHeader(http.StatusOK)
 }
 
@@ -26,7 +32,7 @@ func (ds *ZabbixDatasource) ZabbixAPIHandler(rw http.ResponseWriter, req *http.R
 		return
 	}
 
-	body, err := ioutil.ReadAll(req.Body)
+	body, err := io.ReadAll(req.Body)
 	defer req.Body.Close()
 	if err != nil || len(body) == 0 {
 		writeError(rw, http.StatusBadRequest, err)
@@ -67,7 +73,7 @@ func (ds *ZabbixDatasource) DBConnectionPostProcessingHandler(rw http.ResponseWr
 		return
 	}
 
-	body, err := ioutil.ReadAll(req.Body)
+	body, err := io.ReadAll(req.Body)
 	defer req.Body.Close()
 	if err != nil || len(body) == 0 {
 		writeError(rw, http.StatusBadRequest, err)
@@ -95,6 +101,9 @@ func (ds *ZabbixDatasource) DBConnectionPostProcessingHandler(rw http.ResponseWr
 	reqData.Query.TimeRange.To = time.Unix(reqData.TimeRange.To, 0)
 
 	frames, err := dsInstance.applyDataProcessing(req.Context(), &reqData.Query, reqData.Series, true)
+	if err != nil {
+		writeError(rw, http.StatusInternalServerError, err)
+	}
 
 	resultJson, err := json.Marshal(frames)
 	if err != nil {
@@ -103,7 +112,11 @@ func (ds *ZabbixDatasource) DBConnectionPostProcessingHandler(rw http.ResponseWr
 
 	rw.Header().Add("Content-Type", "application/json")
 	rw.WriteHeader(http.StatusOK)
-	rw.Write(resultJson)
+
+	_, err = rw.Write(resultJson)
+	if err != nil {
+		ds.logger.Warn("Error writing response")
+	}
 
 }
 
@@ -115,7 +128,11 @@ func writeResponse(rw http.ResponseWriter, result *ZabbixAPIResourceResponse) {
 
 	rw.Header().Add("Content-Type", "application/json")
 	rw.WriteHeader(http.StatusOK)
-	rw.Write(resultJson)
+
+	_, err = rw.Write(resultJson)
+	if err != nil {
+		log.DefaultLogger.Warn("Error writing response")
+	}
 }
 
 func writeError(rw http.ResponseWriter, statusCode int, err error) {
@@ -132,5 +149,9 @@ func writeError(rw http.ResponseWriter, statusCode int, err error) {
 
 	rw.Header().Add("Content-Type", "application/json")
 	rw.WriteHeader(http.StatusInternalServerError)
-	rw.Write(b)
+
+	_, err = rw.Write(b)
+	if err != nil {
+		log.DefaultLogger.Warn("Error writing response")
+	}
 }

pkg/datasource/zabbix.go

@@ -56,6 +56,10 @@ func (ds *ZabbixDatasourceInstance) queryNumericItems(ctx context.Context, query
 	var items []*zabbix.Item
 	var err error
 	zabbixVersion, err := ds.zabbix.GetVersion(ctx)
+	if err != nil {
+		ds.logger.Warn("Error getting Zabbix version")
+	}
+
 	if zabbixVersion >= 54 {
 		items, err = ds.zabbix.GetItems(ctx, groupFilter, hostFilter, itemTagFilter, itemFilter, "num", showDisabled)
 	} else {

pkg/datasource/zabbix_test.go

@@ -8,22 +8,13 @@ import (
 	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
 )
 
-var emptyParams = map[string]interface{}{}
-
 var basicDatasourceInfo = &backend.DataSourceInstanceSettings{
 	ID:       1,
 	Name:     "TestDatasource",
 	URL:      "http://zabbix.org/zabbix",
 	JSONData: []byte(`{"username":"username", "password":"password", "cacheTTL":"10m", "authType":"token"}`),
 }
 
-func mockZabbixQuery(method string, params zabbix.ZabbixAPIParams) *zabbix.ZabbixAPIRequest {
-	return &zabbix.ZabbixAPIRequest{
-		Method: method,
-		Params: params,
-	}
-}
-
 func MockZabbixDataSource(body string, statusCode int) *ZabbixDatasourceInstance {
 	zabbixSettings, _ := settings.ReadZabbixSettings(basicDatasourceInfo)
 	zabbixClient, _ := zabbix.MockZabbixClient(basicDatasourceInfo, body, statusCode)

pkg/httpclient/httpclient.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	simplejson "github.com/bitly/go-simplejson"
+
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/httpclient"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
@@ -14,6 +15,10 @@ import (
 // New creates new HTTP client.
 func New(dsInfo *backend.DataSourceInstanceSettings, timeout time.Duration) (*http.Client, error) {
 	clientOptions, err := dsInfo.HTTPClientOptions()
+	if err != nil {
+		return nil, err
+	}
+
 	clientOptions.Timeouts.Timeout = timeout
 
 	tlsSkipVerify, err := getTLSSkipVerify(dsInfo)

pkg/timeseries/agg_functions.go

@@ -96,7 +96,7 @@ func AggPercentile(n float64) AggregationFunc {
 			return nil
 		}
 
-		sort.Sort(sort.Float64Slice(values))
+		sort.Float64s(values)
 		percentileIndex := int(math.Floor(float64(len(values)) * n / 100))
 		percentile := values[percentileIndex]
 		return &percentile

pkg/timeseries/align.go

@@ -129,12 +129,11 @@ func PrepareForStack(series []*TimeSeriesData) []*TimeSeriesData {
 		p := s.TS[0]
 		pNext := s.TS[1]
 		interpolatedSeries := make([]TimePoint, 0)
-		interpolatedTS := interpolatedTimeStamps[0]
 		interpolatedTSIdx := 0
 
 		// Insert nulls before the first point
 		for i := 0; i < len(interpolatedTimeStamps); i++ {
-			interpolatedTS = interpolatedTimeStamps[i]
+			interpolatedTS := interpolatedTimeStamps[i]
 			if interpolatedTS.Before(p.Time) {
 				interpolatedSeries = append(interpolatedSeries, TimePoint{Time: interpolatedTS, Value: nil})
 			} else {

pkg/timeseries/timeseries.go

@@ -4,8 +4,6 @@ import (
 	"math"
 	"sort"
 	"time"
-
-	"github.com/grafana/grafana-plugin-sdk-go/data"
 )
 
 func NewTimeSeriesData() *TimeSeriesData {
@@ -309,36 +307,3 @@ func findNearestLeft(series TimeSeries, pointIndex int) *TimePoint {
 	}
 	return nil
 }
-
-func getTimeFieldIndex(frame *data.Frame) int {
-	for i := 0; i < len(frame.Fields); i++ {
-		if frame.Fields[i].Type() == data.FieldTypeTime {
-			return i
-		}
-	}
-
-	return -1
-}
-
-func getTimestampAt(frame *data.Frame, index int) *time.Time {
-	timeFieldIdx := getTimeFieldIndex(frame)
-	if timeFieldIdx < 0 {
-		return nil
-	}
-
-	tsValue := frame.Fields[timeFieldIdx].At(index)
-	ts, ok := tsValue.(time.Time)
-	if !ok {
-		return nil
-	}
-
-	return &ts
-}
-
-func setTimeAt(frame *data.Frame, frameTs time.Time, index int) {
-	for _, field := range frame.Fields {
-		if field.Type() == data.FieldTypeTime {
-			field.Insert(index, frameTs)
-		}
-	}
-}

pkg/zabbix/methods.go

@@ -115,6 +115,9 @@ func (ds *Zabbix) GetItems(
 		itemTagFilter = strings.Join(tagStrs, ",")
 	}
 	allItems, err = ds.GetAllItems(ctx, hostids, nil, itemType, showDisabled, itemTagFilter)
+	if err != nil {
+		return nil, err
+	}
 
 	return filterItemsByQuery(allItems, itemFilter)
 }
@@ -153,6 +156,9 @@ func (ds *Zabbix) GetItemsBefore54(
 	} else if appFilter == "" && len(hostids) > 0 {
 		allItems, err = ds.GetAllItems(ctx, hostids, nil, itemType, showDisabled, "")
 	}
+	if err != nil {
+		return nil, err
+	}
 
 	return filterItemsByQuery(allItems, itemFilter)
 }
@@ -239,7 +245,11 @@ func (ds *Zabbix) GetItemTags(ctx context.Context, groupFilter string, hostFilte
 	var allItems []*Item
 	itemType := "num"
 	showDisabled := false
+
 	allItems, err = ds.GetAllItems(ctx, hostids, nil, itemType, showDisabled, "")
+	if err != nil {
+		return nil, err
+	}
 
 	var allTags []ItemTag
 	tagsMap := make(map[string]ItemTag)
@@ -397,7 +407,7 @@ func (ds *Zabbix) GetAllItems(ctx context.Context, hostids []string, appids []st
 		}
 	}
 
-	if showDisabled == false {
+	if !showDisabled {
 		params["monitored"] = true
 	}
 
@@ -521,12 +531,3 @@ func (ds *Zabbix) GetVersion(ctx context.Context) (int, error) {
 	versionNum, err := strconv.Atoi(version)
 	return versionNum, err
 }
-
-func isAppMethodNotFoundError(err error) bool {
-	if err == nil {
-		return false
-	}
-
-	message := err.Error()
-	return message == `Method not found. Incorrect API "application".`
-}

pkg/zabbix/utils.go

@@ -12,7 +12,7 @@ func (item *Item) ExpandItemName() string {
 	name := item.Name
 	key := item.Key
 
-	if strings.Index(key, "[") == -1 {
+	if !strings.Contains(key, "[") {
 		return name
 	}
 
@@ -34,14 +34,13 @@ func expandItems(items []*Item) []*Item {
 }
 
 func splitKeyParams(paramStr string) []string {
-	paramRunes := []rune(paramStr)
 	params := []string{}
 	quoted := false
 	inArray := false
 	splitSymbol := ","
 	param := ""
 
-	for _, r := range paramRunes {
+	for _, r := range paramStr {
 		symbol := string(r)
 		if symbol == `"` && inArray {
 			param += symbol

pkg/zabbixapi/testing.go

@@ -2,7 +2,7 @@ package zabbixapi
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 
@@ -36,7 +36,7 @@ func MockZabbixAPI(body string, statusCode int) (*ZabbixAPI, error) {
 		httpClient: NewTestClient(func(req *http.Request) *http.Response {
 			return &http.Response{
 				StatusCode: statusCode,
-				Body:       ioutil.NopCloser(bytes.NewBufferString(body)),
+				Body:       io.NopCloser(bytes.NewBufferString(body)),
 				Header:     make(http.Header),
 			}
 		}),