refactor(api): extract common interface{} to int64 conversion utility (#539)

Add ParseInt64 utility function in pkg/api/params.go to eliminate
duplicated type conversion logic across toolsets. This also fixes a bug
in nodes.go where `case int:` was missing the assignment statement.

Signed-off-by: Marc Nuri <[email protected]>

Author: manusa

pkg/api/params.go

@@ -0,0 +1,28 @@
+package api
+
+import "fmt"
+
+// ErrInvalidInt64Type is returned when a value cannot be converted to int64.
+type ErrInvalidInt64Type struct {
+	Value interface{}
+}
+
+func (e *ErrInvalidInt64Type) Error() string {
+	return fmt.Sprintf("expected integer, got %T", e.Value)
+}
+
+// ParseInt64 converts an interface{} value (typically from JSON-decoded tool arguments)
+// to int64. Handles float64 (JSON numbers), int, and int64 types.
+// Returns the converted value and nil error on success, or 0 and an ErrInvalidInt64Type if the type is unsupported.
+func ParseInt64(value interface{}) (int64, error) {
+	switch v := value.(type) {
+	case float64:
+		return int64(v), nil
+	case int:
+		return int64(v), nil
+	case int64:
+		return v, nil
+	default:
+		return 0, &ErrInvalidInt64Type{Value: value}
+	}
+}

pkg/api/params_test.go

@@ -0,0 +1,105 @@
+package api
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type ParamsSuite struct {
+	suite.Suite
+}
+
+func TestParamsSuite(t *testing.T) {
+	suite.Run(t, new(ParamsSuite))
+}
+
+func (s *ParamsSuite) TestParseInt64() {
+	s.Run("float64 value is converted to int64", func() {
+		result, err := ParseInt64(float64(42.0))
+		s.NoError(err)
+		s.Equal(int64(42), result)
+	})
+
+	s.Run("float64 with decimal truncates to int64", func() {
+		result, err := ParseInt64(float64(42.9))
+		s.NoError(err)
+		s.Equal(int64(42), result)
+	})
+
+	s.Run("int value is converted to int64", func() {
+		result, err := ParseInt64(int(100))
+		s.NoError(err)
+		s.Equal(int64(100), result)
+	})
+
+	s.Run("int64 value is returned as-is", func() {
+		result, err := ParseInt64(int64(999))
+		s.NoError(err)
+		s.Equal(int64(999), result)
+	})
+
+	s.Run("negative float64 value is converted correctly", func() {
+		result, err := ParseInt64(float64(-10.0))
+		s.NoError(err)
+		s.Equal(int64(-10), result)
+	})
+
+	s.Run("negative int value is converted correctly", func() {
+		result, err := ParseInt64(int(-5))
+		s.NoError(err)
+		s.Equal(int64(-5), result)
+	})
+
+	s.Run("zero value is handled correctly", func() {
+		result, err := ParseInt64(float64(0))
+		s.NoError(err)
+		s.Equal(int64(0), result)
+	})
+
+	s.Run("string value returns error", func() {
+		result, err := ParseInt64("not a number")
+		s.Error(err)
+		s.Equal(int64(0), result)
+		s.Contains(err.Error(), "string")
+	})
+
+	s.Run("nil value returns error", func() {
+		result, err := ParseInt64(nil)
+		s.Error(err)
+		s.Equal(int64(0), result)
+	})
+
+	s.Run("bool value returns error", func() {
+		result, err := ParseInt64(true)
+		s.Error(err)
+		s.Equal(int64(0), result)
+		s.Contains(err.Error(), "bool")
+	})
+
+	s.Run("slice value returns error", func() {
+		result, err := ParseInt64([]int{1, 2, 3})
+		s.Error(err)
+		s.Equal(int64(0), result)
+	})
+
+	s.Run("map value returns error", func() {
+		result, err := ParseInt64(map[string]int{"a": 1})
+		s.Error(err)
+		s.Equal(int64(0), result)
+	})
+}
+
+func (s *ParamsSuite) TestErrInvalidInt64Type() {
+	s.Run("error includes type information", func() {
+		err := &ErrInvalidInt64Type{Value: "test"}
+		s.Contains(err.Error(), "string")
+	})
+
+	s.Run("error can be type asserted", func() {
+		_, err := ParseInt64("invalid")
+		var typeErr *ErrInvalidInt64Type
+		s.ErrorAs(err, &typeErr)
+		s.Equal("invalid", typeErr.Value)
+	})
+}

pkg/toolsets/core/nodes.go

@@ -108,15 +108,10 @@ func nodesLog(params api.ToolHandlerParams) (*api.ToolCallResult, error) {
 	tailLines := params.GetArguments()["tailLines"]
 	var tailInt int64
 	if tailLines != nil {
-		// Convert to int64 - safely handle both float64 (JSON number) and int types
-		switch v := tailLines.(type) {
-		case float64:
-			tailInt = int64(v)
-		case int:
-		case int64:
-			tailInt = v
-		default:
-			return api.NewToolCallResult("", fmt.Errorf("failed to parse tail parameter: expected integer, got %T", tailLines)), nil
+		var err error
+		tailInt, err = api.ParseInt64(tailLines)
+		if err != nil {
+			return api.NewToolCallResult("", fmt.Errorf("failed to parse tailLines parameter: %w", err)), nil
 		}
 	}
 	ret, err := params.NodesLog(params, name, query, tailInt)

pkg/toolsets/core/pods.go

@@ -397,16 +397,10 @@ func podsLog(params api.ToolHandlerParams) (*api.ToolCallResult, error) {
 	tail := params.GetArguments()["tail"]
 	var tailInt int64
 	if tail != nil {
-		// Convert to int64 - safely handle both float64 (JSON number) and int types
-		switch v := tail.(type) {
-		case float64:
-			tailInt = int64(v)
-		case int:
-			tailInt = int64(v)
-		case int64:
-			tailInt = v
-		default:
-			return api.NewToolCallResult("", fmt.Errorf("failed to parse tail parameter: expected integer, got %T", tail)), nil
+		var err error
+		tailInt, err = api.ParseInt64(tail)
+		if err != nil {
+			return api.NewToolCallResult("", fmt.Errorf("failed to parse tail parameter: %w", err)), nil
 		}
 	}
 

pkg/toolsets/core/resources.go

@@ -346,16 +346,11 @@ func resourcesScale(params api.ToolHandlerParams) (*api.ToolCallResult, error) {
 }
 
 func parseScaleValue(desiredScale interface{}) (int64, error) {
-	switch s := desiredScale.(type) {
-	case float64:
-		return int64(s), nil
-	case int:
-		return int64(s), nil
-	case int64:
-		return s, nil
-	default:
-		return 0, fmt.Errorf("failed to parse scale parameter: expected integer, got %T", desiredScale)
+	v, err := api.ParseInt64(desiredScale)
+	if err != nil {
+		return 0, fmt.Errorf("failed to parse scale parameter: %w", err)
 	}
+	return v, nil
 }
 
 func parseGroupVersionKind(arguments map[string]interface{}) (*schema.GroupVersionKind, error) {

pkg/toolsets/kiali/logs.go

@@ -86,14 +86,11 @@ func workloadLogsHandler(params api.ToolHandlerParams) (*api.ToolCallResult, err
 
 	// Convert tail to maxLines
 	if tail != nil {
-		switch v := tail.(type) {
-		case float64:
-			maxLines = fmt.Sprintf("%.0f", v)
-		case int:
-			maxLines = fmt.Sprintf("%d", v)
-		case int64:
-			maxLines = fmt.Sprintf("%d", v)
+		tailInt, err := api.ParseInt64(tail)
+		if err != nil {
+			return api.NewToolCallResult("", fmt.Errorf("failed to parse tail parameter: %w", err)), nil
 		}
+		maxLines = fmt.Sprintf("%d", tailInt)
 	}
 
 	// If no container specified, we need to get workload details first to find the main app container