refactor: Improves idiomatic err usage

Author: NeedleInAJayStack

pkg/plugin/datasource.go

@@ -37,9 +37,9 @@ func NewDatasource(ctx context.Context, settings backend.DataSourceInstanceSetti
 
 	// settings contains normal inputs in the .JSONData field in JSON byte form
 	var options Options
-	jsonErr := json.Unmarshal(settings.JSONData, &options)
-	if jsonErr != nil {
-		return nil, jsonErr
+	err := json.Unmarshal(settings.JSONData, &options)
+	if err != nil {
+		return nil, fmt.Errorf("datasource options: %w", err)
 	}
 	url := options.Url
 	username := options.Username
@@ -57,9 +57,9 @@ func NewDatasource(ctx context.Context, settings backend.DataSourceInstanceSetti
 		return nil, fmt.Errorf("new http client: %w", err)
 	}
 	client := client.NewClientFromHTTP(url, username, password, httpClient)
-	openErr := client.Open()
-	if openErr != nil {
-		return nil, openErr
+	err = client.Open()
+	if err != nil {
+		return nil, fmt.Errorf("haystack client opening: %w", err)
 	}
 	datasource := Datasource{client: client}
 	return &datasource, nil
@@ -121,10 +121,10 @@ func (datasource *Datasource) query(ctx context.Context, pCtx backend.PluginCont
 	// Unmarshal the JSON into our queryModel.
 	var model QueryModel
 
-	jsonErr := json.Unmarshal(query.JSON, &model)
-	if jsonErr != nil {
-		log.DefaultLogger.Error(jsonErr.Error())
-		return backend.ErrDataResponse(backend.StatusBadRequest, fmt.Sprintf("json unmarshal failure: %v", jsonErr.Error()))
+	err := json.Unmarshal(query.JSON, &model)
+	if err != nil {
+		log.DefaultLogger.Error(err.Error())
+		return backend.ErrDataResponse(backend.StatusBadRequest, fmt.Sprintf("json unmarshal failure: %v", err.Error()))
 	}
 
 	variables := map[string]string{
@@ -264,11 +264,7 @@ func (datasource *Datasource) query(ctx context.Context, pCtx backend.PluginCont
 func responseFromGrids(grids []haystack.Grid) backend.DataResponse {
 	frames := data.Frames{}
 	for _, grid := range grids {
-		frame, frameErr := dataFrameFromGrid(grid)
-		if frameErr != nil {
-			log.DefaultLogger.Error(frameErr.Error())
-			return backend.ErrDataResponse(backend.StatusBadRequest, fmt.Sprintf("Frame conversion failure: %v", frameErr.Error()))
-		}
+		frame := dataFrameFromGrid(grid)
 		frames = append(frames, frame)
 	}
 
@@ -337,13 +333,13 @@ func (datasource *Datasource) hisRead(point haystack.Row, timeRange backend.Time
 
 	// Must convert input date range to the point's timezone.
 	// See https://github.com/skyfoundry/haystack-java/blob/30380dbbe4b5d9be8eb3f400195b0cdcdcc67b95/src/main/java/org/projecthaystack/server/HServer.java#L328
-	start, startErr := haystack.NewDateTimeFromGo(timeRange.From).ToTz(tz.String())
-	if startErr != nil {
-		return haystack.EmptyGrid(), startErr
+	start, err := haystack.NewDateTimeFromGo(timeRange.From).ToTz(tz.String())
+	if err != nil {
+		return haystack.EmptyGrid(), fmt.Errorf("start time: %w", err)
 	}
-	end, endErr := haystack.NewDateTimeFromGo(timeRange.To).ToTz(tz.String())
-	if endErr != nil {
-		return haystack.EmptyGrid(), endErr
+	end, err := haystack.NewDateTimeFromGo(timeRange.To).ToTz(tz.String())
+	if err != nil {
+		return haystack.EmptyGrid(), fmt.Errorf("end time: %w", err)
 	}
 
 	return datasource.withRetry(
@@ -419,7 +415,7 @@ func (datasource *Datasource) withRetry(
 }
 
 // dataFrameFromGrid converts a haystack grid to a Grafana data frame
-func dataFrameFromGrid(grid haystack.Grid) (*data.Frame, error) {
+func dataFrameFromGrid(grid haystack.Grid) *data.Frame {
 	fields := []*data.Field{}
 
 	for _, col := range grid.Cols() {
@@ -531,7 +527,7 @@ func dataFrameFromGrid(grid haystack.Grid) (*data.Frame, error) {
 	frame := data.NewFrame("response", fields...)
 	frameName := disFromMeta(grid.Meta(), "")
 	frame.Name = frameName
-	return frame, nil
+	return frame
 }
 
 // disFromMeta returns the display name using metadata. It falls back to the provided string if no other name can be found