#62 Add new processor to skip arguments in declaration

example/actions/arguments/action.yaml

@@ -19,5 +19,5 @@ runtime:
   command:
     - sh
     - /action/main.sh
-    - "{{ .firstoption }}"
-    - "{{ .secondoption }}"
+    - "{{ .firstoption | removeLineIfNil }}"
+    - "{{ if not (isNil .secondoption) }}--secondoption={{ .secondoption }}{{ else }}{{ removeLine }}{{ end }}"

pkg/action/loader.go

@@ -10,6 +10,10 @@ import (
 	"text/template"
 )
 
+const tokenRmLine = "<TOKEN_REMOVE_THIS_LINE>"
+
+var rgxTokenRmLine = regexp.MustCompile(`.*` + tokenRmLine + `.*\n?`)
+
 // Loader is an interface for loading an action file.
 type Loader interface {
 	// Content returns the raw file content.
@@ -88,6 +92,27 @@ func (err errMissingVar) Error() string {
 	return fmt.Sprintf("the following variables were used but never defined: %v", f)
 }
 
+// actionTplFuncs defined template functions available during parsing of an action yaml.
+func actionTplFuncs() template.FuncMap {
+	return template.FuncMap{
+		// Checks if a value is nil. Used in conditions.
+		"isNil": func(v any) bool {
+			return v == nil
+		},
+		// Removes a line if a given value is nil or pass through.
+		"removeLineIfNil": func(v any) any {
+			if v == nil {
+				return tokenRmLine
+			}
+			return v
+		},
+		// Removes current line.
+		"removeLine": func() string {
+			return tokenRmLine
+		},
+	}
+}
+
 func (p inputProcessor) Process(ctx LoadContext, b []byte) ([]byte, error) {
 	if ctx.Action == nil {
 		return b, nil
@@ -99,7 +124,8 @@ func (p inputProcessor) Process(ctx LoadContext, b []byte) ([]byte, error) {
 	addPredefinedVariables(data, a)
 
 	// Parse action without variables to validate
-	tpl := template.New(a.ID)
+	tpl := template.New(a.ID).Funcs(actionTplFuncs())
+
 	_, err := tpl.Parse(string(b))
 	if err != nil {
 		// Check if variables have dashes to show the error properly.
@@ -141,6 +167,9 @@ Action definition is correct, but dashes are not allowed in templates, replace "
 		}
 	}
 
+	// Remove all lines containing [tokenRmLine].
+	res = rgxTokenRmLine.ReplaceAll(res, []byte(""))
+
 	return res, nil
 }
 

pkg/action/loader_test.go

@@ -67,6 +67,15 @@ func Test_InputProcessor(t *testing.T) {
 	res, err = proc.Process(ctx, []byte(s))
 	assert.Equal(t, err, errMissingVar{vars: map[string]struct{}{"optUnd": {}, "arg2": {}}})
 	assert.Equal(t, "", string(res))
+
+	// Remove line if a variable not exists or is nil.
+	s = `- "{{ .arg1 | removeLineIfNil }}"
+- "{{ .optUnd | removeLineIfNil }}" # Piping with new line
+- "{{ if not (isNil .arg1) }}arg1 is not nil{{end}}"
+- "{{ if isNil .optUnd }}{{ removeLine }}{{ end }}" # Function call without new line`
+	res, err = proc.Process(ctx, []byte(s))
+	assert.NoError(t, err)
+	assert.Equal(t, "- \"arg1\"\n- \"arg1 is not nil\"\n", string(res))
 }
 
 func Test_YamlTplCommentsProcessor(t *testing.T) {