Improve and export errors in packages

lib/go/csvframer/CHANGELOG.md

@@ -1,5 +1,9 @@
 # @grafana/infinity-csvframer
 
+## 1.0.1
+
+- improved error messages
+
 ## 1.0.0
 
 - chore release

lib/go/csvframer/errors.go

@@ -0,0 +1,8 @@
+package csvframer
+
+import "errors"
+
+var (
+	ErrEmptyCsv = errors.New("empty/invalid csv")
+	ErrReadingCsvResponse = errors.New("error reading csv response")
+)

lib/go/csvframer/framer.go

@@ -23,7 +23,7 @@ type FramerOptions struct {
 
 func ToFrame(csvString string, options FramerOptions) (frame *data.Frame, err error) {
 	if strings.TrimSpace(csvString) == "" {
-		return frame, errors.New("empty/invalid csv")
+		return frame, ErrEmptyCsv
 	}
 	r := csv.NewReader(strings.NewReader(csvString))
 	r.LazyQuotes = true
@@ -47,7 +47,7 @@ func ToFrame(csvString string, options FramerOptions) (frame *data.Frame, err er
 			continue
 		}
 		if !options.SkipLinesWithError {
-			return frame, fmt.Errorf("error reading csv response. %w, %v", err, record)
+			return frame, errors.Join(ErrReadingCsvResponse, fmt.Errorf("%w, %v", err, record))
 		}
 	}
 	out := []interface{}{}

lib/go/csvframer/framer_test.go

@@ -1,7 +1,6 @@
 package csvframer_test
 
 import (
-	"errors"
 	"strings"
 	"testing"
 
@@ -21,7 +20,7 @@ func TestCsvStringToFrame(t *testing.T) {
 	}{
 		{
 			name:      "empty csv should return error",
-			wantError: errors.New("empty/invalid csv"),
+			wantError: csvframer.ErrEmptyCsv,
 		},
 		{
 			name:      "valid csv should not return error",

lib/go/framesql/CHANGELOG.md

@@ -1,5 +1,9 @@
 # @grafana/infinity-framesql
 
+## 1.0.1
+
+- improved error messages
+
 ## 1.0.0
 
 - chore release

lib/go/framesql/errors.go

@@ -0,0 +1,7 @@
+package framesql
+
+import "errors"
+
+var (
+	ErrEmptySummarizeExpression = errors.New("empty/invalid summarize expression")
+)

lib/go/framesql/frame.go

@@ -2,7 +2,6 @@ package framesql
 
 import (
 	"errors"
-	"fmt"
 	"regexp"
 	"strings"
 
@@ -12,7 +11,7 @@ import (
 
 func EvaluateInFrame(expression string, input *data.Frame) (any, error) {
 	if strings.TrimSpace(expression) == "" {
-		return nil, errors.New(strings.TrimSpace(fmt.Sprintf("empty/invalid expression. %s", expression)))
+		return nil, ErrEmptySummarizeExpression
 	}
 	parsedExpression, err := govaluate.NewEvaluableExpressionWithFunctions(expression, expressionFunctions)
 	if err != nil {

lib/go/framesql/frame_test.go

@@ -1,7 +1,6 @@
 package framesql_test
 
 import (
-	"errors"
 	"testing"
 
 	"github.com/grafana/grafana-plugin-sdk-go/data"
@@ -19,7 +18,7 @@ func TestEvaluateInFrame(t *testing.T) {
 		wantErr    error
 	}{
 		{
-			wantErr: errors.New("empty/invalid expression."),
+			wantErr: framesql.ErrEmptySummarizeExpression,
 		},
 		{
 			input:      data.NewFrame("test", data.NewField("sample", nil, []*float64{toFP(1), toFP(2), toFP(0.5), toFP(1.5)})),

lib/go/transformations/CHANGELOG.md

@@ -1,5 +1,9 @@
 # @grafana/infinity-transformations
 
+## 1.0.1
+
+- improved error messages
+
 ## 1.0.0
 
 - chore release

lib/go/transformations/errors.go

@@ -0,0 +1,14 @@
+package transformations
+
+import "errors"
+
+var (
+	ErrSummarizeByFieldNotFound = errors.New("summarize by field not found. Not applying summarize")
+	ErrNotUniqueFieldNames = errors.New("field names are not unique. Not applying filter")
+	ErrEvaluatingFilterExpression = errors.New("error evaluating filter expression")
+
+	ErrMergeTransformationNoFrameSupplied = errors.New("no frames supplied for merge frame transformation")
+	ErrMergeTransformationDifferentFields = errors.New("unable to merge fields due to different fields")
+	ErrMergeTransformationDifferentFieldNames = errors.New("unable to merge field due to different field names")
+	ErrMergeTransformationDifferentFieldTypes = errors.New("unable to merge fields due to different field types")
+)

lib/go/transformations/filterExpression.go

@@ -42,7 +42,7 @@ func ApplyFilter(frame *data.Frame, filterExpression string) (*data.Frame, error
 	fieldKeys := map[string]bool{}
 	for _, field := range frame.Fields {
 		if fieldKeys[field.Name] {
-			return frame, errors.New("field names are not unique. Not applying filter")
+			return frame, ErrNotUniqueFieldNames
 		}
 		fieldKeys[field.Name] = true
 	}
@@ -57,7 +57,7 @@ func ApplyFilter(frame *data.Frame, filterExpression string) (*data.Frame, error
 		}
 		result, err := parsedExpression.Evaluate(parameters)
 		if err != nil {
-			return frame, fmt.Errorf("error evaluating filter expression for row %d. error: %w. Not applying filter", inRowIdx, err)
+			return frame, errors.Join(ErrEvaluatingFilterExpression,  fmt.Errorf("error: %w. row %d. Not applying filter", err, inRowIdx))
 		}
 		if currentMatch, ok := result.(bool); ok {
 			match = &currentMatch

lib/go/transformations/merge.go

@@ -1,8 +1,6 @@
 package transformations
 
 import (
-	"errors"
-
 	"github.com/grafana/grafana-plugin-sdk-go/data"
 )
 
@@ -17,22 +15,22 @@ type MergeFramesOptions struct {
 // Ref: https://github.com/grafana/grafana/blob/v9.5.2/packages/grafana-data/src/transformations/transformers/merge.ts
 func Merge(inputFrames []*data.Frame, option MergeFramesOptions) (*data.Frame, error) {
 	if len(inputFrames) < 1 {
-		return nil, errors.New("no frames supplied for merge frame transformation")
+		return nil, ErrMergeTransformationNoFrameSupplied
 	}
 	outFrame := inputFrames[0]
 	for frameId, frame := range inputFrames {
 		if frameId == 0 {
 			continue
 		}
 		if len(outFrame.Fields) != len(frame.Fields) {
-			return nil, errors.New("unable to merge fields due to different fields")
+			return nil, ErrMergeTransformationDifferentFields
 		}
 		for fi, f := range frame.Fields {
 			if f.Name != outFrame.Fields[fi].Name {
-				return nil, errors.New("unable to merge field due to different field names")
+				return nil, ErrMergeTransformationDifferentFieldNames
 			}
 			if f.Type() != outFrame.Fields[fi].Type() {
-				return nil, errors.New("unable to merge fields due to different field types")
+				return nil, ErrMergeTransformationDifferentFieldTypes
 			}
 		}
 		for rowId := 0; rowId < frame.Rows(); rowId++ {

lib/go/transformations/summarize.go

@@ -79,7 +79,7 @@ func GetSummarizeByFrame(frame *data.Frame, expression, by string, alias string)
 		}
 	}
 	if byField == nil {
-		return frame, errors.New("summarize by field not found. Not applying summarize")
+		return frame, ErrSummarizeByFieldNotFound
 	}
 	uniqueValuesArray := []any{}
 	uniqueValues := map[any]bool{}