Handle db connection response on the backend

pkg/datasource/models.go

@@ -3,6 +3,7 @@ package datasource
 import (
 	"encoding/json"
 	"fmt"
+	"github.com/alexanderzobnin/grafana-zabbix/pkg/timeseries"
 	"strconv"
 	"time"
 
@@ -44,6 +45,11 @@ type ZabbixDatasourceSettings struct {
 	DisableReadOnlyUsersAck bool `json:"disableReadOnlyUsersAck"`
 }
 
+type DBConnectionPostProcessingRequest struct {
+	Query  QueryModel                   `json:"query"`
+	Series []*timeseries.TimeSeriesData `json:"series"`
+}
+
 type ZabbixAPIResourceRequest struct {
 	DatasourceId int64                  `json:"datasourceId"`
 	Method       string                 `json:"method"`

pkg/datasource/resource_handler.go

@@ -60,6 +60,47 @@ func (ds *ZabbixDatasource) ZabbixAPIHandler(rw http.ResponseWriter, req *http.R
 	writeResponse(rw, result)
 }
 
+func (ds *ZabbixDatasource) DBConnectionPostProcessingHandler(rw http.ResponseWriter, req *http.Request) {
+	if req.Method != http.MethodPost {
+		return
+	}
+
+	body, err := ioutil.ReadAll(req.Body)
+	defer req.Body.Close()
+	if err != nil || len(body) == 0 {
+		writeError(rw, http.StatusBadRequest, err)
+		return
+	}
+
+	var reqData DBConnectionPostProcessingRequest
+	err = json.Unmarshal(body, &reqData)
+	if err != nil {
+		ds.logger.Error("Cannot unmarshal request", "error", err.Error())
+		writeError(rw, http.StatusInternalServerError, err)
+		return
+	}
+
+	pluginCxt := httpadapter.PluginConfigFromContext(req.Context())
+	dsInstance, err := ds.getDSInstance(pluginCxt)
+	if err != nil {
+		ds.logger.Error("Error loading datasource", "error", err)
+		writeError(rw, http.StatusInternalServerError, err)
+		return
+	}
+
+	frames, err := dsInstance.applyDataProcessing(req.Context(), &reqData.Query, reqData.Series)
+
+	resultJson, err := json.Marshal(frames)
+	if err != nil {
+		writeError(rw, http.StatusInternalServerError, err)
+	}
+
+	rw.Header().Add("Content-Type", "application/json")
+	rw.WriteHeader(http.StatusOK)
+	rw.Write(resultJson)
+
+}
+
 func writeResponse(rw http.ResponseWriter, result *ZabbixAPIResourceResponse) {
 	resultJson, err := json.Marshal(*result)
 	if err != nil {

pkg/datasource/zabbix.go

@@ -1,6 +1,7 @@
 package datasource
 
 import (
+	"github.com/alexanderzobnin/grafana-zabbix/pkg/timeseries"
 	"strings"
 	"time"
 
@@ -134,6 +135,43 @@ func (ds *ZabbixDatasourceInstance) queryNumericDataForItems(ctx context.Context
 	return frames, nil
 }
 
+func (ds *ZabbixDatasourceInstance) applyDataProcessing(ctx context.Context, query *QueryModel, series []*timeseries.TimeSeriesData) ([]*data.Frame, error) {
+	consolidateBy := ds.getConsolidateBy(query)
+
+	// Align time series data if possible
+	useTrend := ds.isUseTrend(query.TimeRange)
+	if !query.Options.DisableDataAlignment && !ds.Settings.DisableDataAlignment && !useTrend {
+		for _, s := range series {
+			if s.Meta.Interval != nil {
+				s.TS = s.TS.Align(*s.Meta.Interval)
+			}
+		}
+	}
+
+	series, err := applyFunctions(series, query.Functions)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, s := range series {
+		if int64(s.Len()) > query.MaxDataPoints && query.Interval > 0 {
+			downsampleFunc := consolidateBy
+			if downsampleFunc == "" {
+				downsampleFunc = "avg"
+			}
+			downsampled, err := applyGroupBy(s.TS, query.Interval.String(), downsampleFunc)
+			if err == nil {
+				s.TS = downsampled
+			} else {
+				ds.logger.Debug("Error downsampling series", "error", err)
+			}
+		}
+	}
+
+	frames := convertTimeSeriesToDataFrames(series)
+	return frames, nil
+}
+
 func (ds *ZabbixDatasourceInstance) getTrendValueType(query *QueryModel) string {
 	trendValue := "avg"