internal: add new blueprintload package

This commit provides a `blueprintload` package that can be used
to load blueprints from json/toml from a path. This will be used
in `bootc-image-builder` and `image-builder-cli` and should
eventually be merged into `images`.

internal/blueprintload/blueprintload.go

@@ -0,0 +1,67 @@
+package blueprintload
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/BurntSushi/toml"
+
+	"github.com/osbuild/images/pkg/blueprint"
+)
+
+// XXX: move this helper into images, share with bib
+func decodeToml(r io.Reader, what string) (*blueprint.Blueprint, error) {
+	dec := toml.NewDecoder(r)
+
+	var conf blueprint.Blueprint
+	_, err := dec.Decode(&conf)
+	if err != nil {
+		return nil, fmt.Errorf("cannot decode %q: %w", what, err)
+	}
+
+	return &conf, nil
+}
+
+func decodeJson(r io.Reader, what string) (*blueprint.Blueprint, error) {
+	dec := json.NewDecoder(r)
+	dec.DisallowUnknownFields()
+
+	var conf blueprint.Blueprint
+	if err := dec.Decode(&conf); err != nil {
+		return nil, fmt.Errorf("cannot decode %q: %w", what, err)
+	}
+	if dec.More() {
+		return nil, fmt.Errorf("multiple configuration objects or extra data found in %q", what)
+	}
+	return &conf, nil
+}
+
+func Load(path string) (*blueprint.Blueprint, error) {
+	var fp io.ReadCloser
+	var err error
+
+	switch path {
+	case "":
+		return &blueprint.Blueprint{}, nil
+	case "-":
+		fp = os.Stdin
+	default:
+		fp, err = os.Open(path)
+		if err != nil {
+			return nil, err
+		}
+		defer fp.Close()
+	}
+
+	switch {
+	case path == "-", filepath.Ext(path) == ".json":
+		return decodeJson(fp, path)
+	case filepath.Ext(path) == ".toml":
+		return decodeToml(fp, path)
+	default:
+		return nil, fmt.Errorf("unsupported file extension for %q (please use .toml or .json)", path)
+	}
+}

internal/blueprintload/blueprintload_test.go

@@ -0,0 +1,72 @@
+package blueprintload_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/osbuild/images/pkg/blueprint"
+
+	"github.com/osbuild/image-builder-cli/internal/blueprintload"
+)
+
+var testBlueprintJSON = `{
+  "customizations": {
+    "user": [
+      {
+	"name": "alice"
+      }
+    ]
+  }
+}`
+
+var testBlueprintTOML = `
+[[customizations.user]]
+name = "alice"
+`
+
+var expectedBlueprint = &blueprint.Blueprint{
+	Customizations: &blueprint.Customizations{
+		User: []blueprint.UserCustomization{
+			{
+				Name: "alice",
+			},
+		},
+	},
+}
+
+func makeTestBlueprint(t *testing.T, name, content string) string {
+	tmpdir := t.TempDir()
+	blueprintPath := filepath.Join(tmpdir, name)
+	err := os.WriteFile(blueprintPath, []byte(content), 0644)
+	assert.NoError(t, err)
+	return blueprintPath
+}
+
+func TestBlueprintLoadJSON(t *testing.T) {
+	for _, tc := range []struct {
+		fname   string
+		content string
+
+		expectedBp    *blueprint.Blueprint
+		expectedError string
+	}{
+		{"bp.json", testBlueprintJSON, expectedBlueprint, ""},
+		{"bp.toml", testBlueprintTOML, expectedBlueprint, ""},
+		{"bp.toml", "wrong-content", nil, `cannot decode .*/bp.toml": toml: `},
+		{"bp.json", "wrong-content", nil, `cannot decode .*/bp.json": invalid `},
+		{"bp", "wrong-content", nil, `unsupported file extension for "/.*/bp"`},
+	} {
+		blueprintPath := makeTestBlueprint(t, tc.fname, tc.content)
+		bp, err := blueprintload.Load(blueprintPath)
+		if tc.expectedError == "" {
+			assert.NoError(t, err)
+			assert.Equal(t, tc.expectedBp, bp)
+		} else {
+			assert.NotNil(t, err)
+			assert.Regexp(t, tc.expectedError, err.Error())
+		}
+	}
+}