Pipeline: Add template function 'isDir'

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

pipeline/template_engine.go

@@ -36,6 +36,7 @@ func renderTemplate(tmplStr string, data interface{}, fm template.FuncMap) (stri
 		"unflatten":  unflattenFunc,
 		"fileExists": fileExistsFunc,
 		"mergeFiles": mergeFilesFunc,
+		"isDir":      isDirFunc,
 	})
 	_, err := tmpl.Parse(tmplStr)
 	if err != nil {

pipeline/template_engine_funcs.go

@@ -73,6 +73,16 @@ func fileExistsFunc(f string) bool {
 	return true
 }
 
+// isDirFunc checks if provided path points to directory.
+// Any error is swallowed and will cause function to return false.
+func isDirFunc(path string) bool {
+	fi, err := os.Stat(path)
+	if err != nil {
+		return false
+	}
+	return fi.IsDir()
+}
+
 // mergeFilesFunc merges 0 or more files into single map[string]interface{}
 func mergeFilesFunc(files ...string) (map[string]interface{}, error) {
 	ds := analytics.NewDocumentSet()

pipeline/template_engine_test.go

@@ -182,3 +182,14 @@ func TestTemplateFuncMergeFilesInvalid(t *testing.T) {
 		_ = os.Remove(f2.Name())
 	})
 }
+
+func TestTemplateFuncIsDir(t *testing.T) {
+	d, err := os.MkdirTemp("", "yt*")
+	assert.NoError(t, err)
+	t.Cleanup(func() {
+		t.Logf("deleting temporary directory %s", d)
+		_ = os.RemoveAll(d)
+	})
+	assert.True(t, isDirFunc(d))
+	assert.False(t, isDirFunc("/i hope/this/path/does/not/exist"))
+}