osbuild: Add validation error logging

osbuild can return a json object with details about manifest validation
errors. This adds support for saving those, and printing them when the
Write function is called. eg. when using composer-cli compose log UUID

Includes tests for new behavior.

internal/osbuild/result.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"sort"
+	"strings"
 )
 
 type Result struct {
@@ -13,6 +14,13 @@ type Result struct {
 	Error    json.RawMessage             `json:"error,omitempty"`
 	Log      map[string]PipelineResult   `json:"log"`
 	Metadata map[string]PipelineMetadata `json:"metadata"`
+	Errors   []ValidationError           `json:"errors,omitempty"`
+	Title    string                      `json:"title,omitempty"`
+}
+
+type ValidationError struct {
+	Message string   `json:"message"`
+	Path    []string `json:"path"`
 }
 
 type PipelineResult []StageResult
@@ -116,6 +124,14 @@ func (res *Result) UnmarshalJSON(data []byte) error {
 }
 
 func (res *Result) Write(writer io.Writer) error {
+	// Error may be included, print them first
+	if res != nil && len(res.Errors) > 0 {
+		fmt.Fprintf(writer, "Error %s\n", res.Title)
+		for _, e := range res.Errors {
+			fmt.Fprintf(writer, "%s: %s\n", strings.Join(e.Path, "."), e.Message)
+		}
+	}
+
 	if res == nil || res.Log == nil {
 		fmt.Fprintf(writer, "The compose result is empty.\n")
 		return nil
@@ -155,3 +171,34 @@ func (res *Result) Write(writer io.Writer) error {
 
 	return nil
 }
+
+// The ValidationError path from osbuild can contain strings or numbers
+// json represents all numbers as float64 but since we know they are really
+// ints any fractional part is truncated when converting to a string.
+func (ve *ValidationError) UnmarshalJSON(data []byte) error {
+	var raw struct {
+		Message string
+		Path    []interface{}
+	}
+	if err := json.Unmarshal(data, &raw); err != nil {
+		return err
+	}
+	ve.Message = raw.Message
+
+	// Convert the path elements to strings
+	var path []string
+	for _, p := range raw.Path {
+		switch v := p.(type) {
+		// json converts numbers, even 0, to float64 not int
+		case float64:
+			path = append(path, fmt.Sprintf("[%0.0f]", v))
+		case string:
+			path = append(path, v)
+		default:
+			return fmt.Errorf("Unexpected type in ValidationError Path: %#v", v)
+		}
+	}
+	ve.Path = path
+
+	return nil
+}

internal/osbuild/result_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/osbuild/osbuild-composer/internal/common"
 )
@@ -203,6 +204,20 @@ func TestUnmarshalV2Failure(t *testing.T) {
 	}
 }
 
+func TestUnmarshalValidationFailure(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+	var result Result
+	err := json.Unmarshal([]byte(validationResultFailure), &result)
+	assert.NoError(err)
+
+	assert.False(result.Success)
+	assert.Equal(result.Title, "JSON Schema validation failed")
+	require.Len(result.Errors, 2)
+	assert.Len(result.Errors[0].Path, 2)
+	assert.Len(result.Errors[1].Path, 5)
+}
+
 func TestWrite(t *testing.T) {
 	assert := assert.New(t)
 	result := Result{
@@ -335,3 +350,29 @@ func TestWriteEmpty(t *testing.T) {
 	assert.NoError(result.Write(&b))
 	assert.Equal("The compose result is empty.\n", b.String())
 }
+
+func TestValidationFailWrite(t *testing.T) {
+	assert := assert.New(t)
+	result := Result{
+		Type:    "https://osbuild.org/validation-error",
+		Success: false,
+		Title:   "JSON Schema validation failed",
+		Errors: []ValidationError{{
+			Message: "Additional properties are not allowed ('homer' was unexpected)",
+			Path:    []string{"sources", "org.osbuild.curl"},
+		}, {
+			Message: "Additional properties are not allowed ('file_contextso' was unexpected)",
+			Path:    []string{"pipelines", "[0]", "stages", "[1]", "options"},
+		}},
+	}
+
+	var b bytes.Buffer
+	assert.NoError(result.Write(&b))
+	expectedOutput := `Error JSON Schema validation failed
+sources.org.osbuild.curl: Additional properties are not allowed ('homer' was unexpected)
+pipelines.[0].stages.[1].options: Additional properties are not allowed ('file_contextso' was unexpected)
+The compose result is empty.
+`
+
+	assert.Equal(expectedOutput, b.String())
+}

internal/osbuild/result_test_data.go

@@ -7872,3 +7872,18 @@ const fullResultRaw = `
   }
 }
 `
+
+const validationResultFailure = `
+{
+	"type": "https://osbuild.org/validation-error",
+	"success": false,
+	"title": "JSON Schema validation failed",
+	"errors": [{
+		"message": "Additional properties are not allowed ('homer' was unexpected)",
+		"path": ["sources", "org.osbuild.curl"]
+	},{
+		"message": "Additional properties are not allowed ('file_contextso' was unexpected)",
+		"path": ["pipelines", 0, "stages", 1, "options"]
+	}]
+}
+`