Pipeline: add template functions to serialize DOM to various formats

Signed-off-by: Richard Kosegi <richard.kosegi@gmail.com>

pipeline/executor.go

@@ -47,7 +47,7 @@ func (ac actContext) Executor() Executor             { return ac.e }
 func (ac actContext) TemplateEngine() TemplateEngine { return ac.t }
 func (ac actContext) Logger() Logger                 { return ac.l }
 func (ac actContext) Snapshot() map[string]interface{} {
-	return dom.DefaultNodeMappingFn(ac.Data()).(map[string]interface{})
+	return dom.DefaultNodeEncoderFn(ac.Data()).(map[string]interface{})
 }
 
 func (p *exec) newCtx(a Action) *actContext {

pipeline/export_op.go

@@ -95,7 +95,7 @@ func (e *ExportOp) Do(ctx ActionContext) (err error) {
 		}
 		return enc(f, d.(dom.Leaf).Value())
 	}
-	return enc(f, dom.DefaultNodeMappingFn(d.(dom.Container)))
+	return enc(f, dom.DefaultNodeEncoderFn(d.(dom.Container)))
 }
 
 func (e *ExportOp) CloneWith(ctx ActionContext) Action {

pipeline/template_engine.go

@@ -30,14 +30,17 @@ type templateEngine struct {
 func renderTemplate(tmplStr string, data interface{}, fm template.FuncMap) (string, error) {
 	tmpl := template.New("tmpl").Funcs(fm)
 	tmpl.Funcs(template.FuncMap{
-		"tpl":        tplFunc(tmpl),
-		"toYaml":     toYamlFunc,
-		"isEmpty":    isEmptyFunc,
-		"unflatten":  unflattenFunc,
-		"fileExists": fileExistsFunc,
-		"mergeFiles": mergeFilesFunc,
-		"isDir":      isDirFunc,
-		"glob":       globFunc,
+		"tpl":            tplFunc(tmpl),
+		"toYaml":         toYamlFunc,
+		"isEmpty":        isEmptyFunc,
+		"unflatten":      unflattenFunc,
+		"fileExists":     fileExistsFunc,
+		"mergeFiles":     mergeFilesFunc,
+		"isDir":          isDirFunc,
+		"glob":           globFunc,
+		"dom2yaml":       dom2yamlFunc,
+		"dom2json":       dom2jsonFunc,
+		"dom2properties": dom2propertiesFunc,
 	})
 	_, err := tmpl.Parse(tmplStr)
 	if err != nil {

pipeline/template_engine_funcs.go

@@ -17,9 +17,9 @@ limitations under the License.
 package pipeline
 
 import (
-	"fmt"
 	"github.com/rkosegi/yaml-toolkit/analytics"
 	"github.com/rkosegi/yaml-toolkit/dom"
+	"github.com/rkosegi/yaml-toolkit/props"
 	"github.com/rkosegi/yaml-toolkit/utils"
 	"os"
 	"path/filepath"
@@ -89,18 +89,32 @@ func globFunc(pattern string) ([]string, error) {
 	return filepath.Glob(pattern)
 }
 
-// mergeFilesFunc merges 0 or more files into single map[string]interface{}
-func mergeFilesFunc(files []string) (map[string]interface{}, error) {
+// mergeFilesFunc merges 0 or more files into dom.Container
+func mergeFilesFunc(files []string) (dom.Container, error) {
 	ds := analytics.NewDocumentSet()
-	result := make(map[string]interface{})
 	for _, f := range files {
 		err := ds.AddDocumentFromFile(f, analytics.DefaultFileDecoderProvider(f))
 		if err != nil {
 			return nil, err
 		}
 	}
-	for k, v := range ds.AsOne().Merged(dom.ListsMergeAppend()).Flatten() {
-		result[k] = fmt.Sprintf("%v", v.Value())
-	}
-	return result, nil
+	return ds.AsOne().Merged(dom.ListsMergeAppend()), nil
+}
+
+func dom2str(c dom.Container, encFn dom.EncoderFunc) (string, error) {
+	var buf strings.Builder
+	err := c.Serialize(&buf, dom.DefaultNodeEncoderFn, encFn)
+	return buf.String(), err
+}
+
+func dom2yamlFunc(c dom.Container) (string, error) {
+	return dom2str(c, dom.DefaultYamlEncoder)
+}
+
+func dom2jsonFunc(c dom.Container) (string, error) {
+	return dom2str(c, dom.DefaultJsonEncoder)
+}
+
+func dom2propertiesFunc(c dom.Container) (string, error) {
+	return dom2str(c, props.EncoderFn)
 }

pipeline/template_engine_test.go

@@ -189,3 +189,45 @@ func TestTemplateFuncGlob(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, 1, len(files))
 }
+
+func TestTemplateFuncDom2Yaml(t *testing.T) {
+	type testCase struct {
+		format string
+		exp    string
+	}
+	d, err := os.MkdirTemp("", "yt*")
+	assert.NoError(t, err)
+	removeDirsLater(t, d)
+	f1, err := os.CreateTemp(d, "yt*.yaml")
+	assert.NoError(t, err)
+	f2, err := os.CreateTemp(d, "yt*.yaml")
+	assert.NoError(t, err)
+	_, err = f1.Write([]byte("a: 1"))
+	assert.NoError(t, err)
+	_, err = f2.Write([]byte("b: 2\n"))
+	assert.NoError(t, err)
+	for _, tc := range []testCase{
+		{
+			format: "properties",
+			exp:    "a=1",
+		},
+		{
+			format: "yaml",
+			exp:    "a: 1",
+		},
+		{
+			format: "json",
+			exp:    `"a": 1`,
+		},
+	} {
+		var res string
+		res, err = renderTemplate(`{{ mergeFiles ( glob ( printf "%s/*.yaml" .Temp ) ) | dom2`+tc.format+` | trim }}`,
+			map[string]interface{}{
+				"Temp": d,
+			}, sprig.HermeticTxtFuncMap())
+		t.Logf("Merged content using format '%s':\n%s", tc.format, res)
+		assert.NoError(t, err)
+		assert.Contains(t, res, tc.exp)
+	}
+	removeFilesLater(t, f1, f2)
+}