feat: template delimiter config

VERSION

@@ -1 +1 @@
-v0.6.1-dev
+v0.7.0

internal/template/delimiter.go

@@ -0,0 +1,81 @@
+package template
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+)
+
+const (
+	prefixBootstrap = "#?bootstrap"
+	defaultStart    = "{{"
+	defaultEnd      = "}}"
+)
+
+type Delimiter struct {
+	Start string
+	End   string
+}
+
+type DelimiterJson struct {
+	Template struct {
+		Delims struct {
+			Start string `json:"start"`
+			End   string `json:"end"`
+		} `json:"delims"`
+	} `json:"template"`
+}
+
+type DelimiterConfig struct {
+	Template string
+}
+
+func NewDelimiterConfig(template string) *DelimiterConfig {
+	return &DelimiterConfig{
+		Template: template,
+	}
+}
+
+// ParseAndCleanup parses the delimiter configuration from the template string
+// and returns the cleaned-up template string along with the Delimiter, or an error if parsing fails.
+// It always returns a Delimiter, defaulting to "{{" and "}}" if no configuration is found.
+// Delimiter configuration string needs to be in the first line of the template, e.g.:
+// #?bootstrap {"template": {"delims": {"start": "<<", "end": ">>"}}}
+func (d *DelimiterConfig) ParseAndCleanup() (string, *Delimiter, error) {
+	if !strings.HasPrefix(d.Template, prefixBootstrap) {
+		return d.Template, &Delimiter{Start: defaultStart, End: defaultEnd}, nil
+	}
+
+	template := strings.TrimSpace(d.Template)
+	firstLineEnd := strings.Index(template, "\n")
+	if firstLineEnd == -1 {
+		firstLineEnd = len(template)
+	}
+
+	jsonPart := strings.TrimSpace(strings.TrimPrefix(template[:firstLineEnd], prefixBootstrap))
+	if jsonPart == "" {
+		return "", nil, errors.New("invalid template delimiter configuration")
+	}
+	var config DelimiterJson
+	if err := json.Unmarshal([]byte(jsonPart), &config); err != nil {
+		return "", nil, errors.New("cannot parse detected template delimiter configuration")
+	}
+
+	template = removeBootstrapConfig(template)
+
+	return template, &Delimiter{Start: config.Template.Delims.Start, End: config.Template.Delims.End}, nil
+}
+
+// removeBootstrapConfig removes the bootstrap configuration line from the template string.
+func removeBootstrapConfig(template string) string {
+	lines := strings.Split(template, "\n")
+	var cleanLines []string
+
+	for _, line := range lines {
+		trimmed := strings.TrimSpace(line)
+		if !strings.HasPrefix(trimmed, prefixBootstrap) {
+			cleanLines = append(cleanLines, line)
+		}
+	}
+	return strings.Join(cleanLines, "\n")
+}

internal/template/delimiter_test.go

@@ -0,0 +1,60 @@
+package template
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDelimiterConfig_parse(t *testing.T) {
+	tests := []struct {
+		name          string
+		template      string
+		wantTemplate  string
+		wantDelimiter *Delimiter
+		wantErr       assert.ErrorAssertionFunc
+	}{
+		{
+			"Valid Delimiter Configuration",
+			`#?bootstrap {"template": {"delims": {"start": "<<", "end": ">>"}}}
+apiVersion: v1`,
+			"apiVersion: v1",
+			&Delimiter{Start: "<<", End: ">>"},
+			assert.NoError,
+		},
+		{
+			"Invalid JSON Configuration",
+			`#?bootstrap {"template": {"delims": {"start": "<<", "end": ">>"}`,
+			"",
+			nil,
+			assert.Error,
+		},
+		{
+			"Missing JSON Configuration",
+			`#?bootstrap`,
+			"",
+			nil,
+			assert.Error,
+		},
+		{
+			"No Delimiter Configuration",
+			`apiVersion: v1
+kind: Pod`,
+			`apiVersion: v1
+kind: Pod`,
+			&Delimiter{"{{", "}}"},
+			assert.NoError,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			template, delim, err := NewDelimiterConfig(tt.template).ParseAndCleanup()
+			if !tt.wantErr(t, err) {
+				return
+			}
+			assert.Equalf(t, tt.wantTemplate, template, "template")
+			assert.Equalf(t, tt.wantDelimiter, delim, "delimiter")
+
+		})
+	}
+}

internal/template/template.go

@@ -307,12 +307,18 @@ func (t *TemplateExecution) WithOCMComponentGetter(ctx context.Context, compGett
 func (t *TemplateExecution) Execute(name, template string, input map[string]interface{}) ([]byte, error) {
 	tmpl := gotmpl.New(name)
 
+	template, delims, err := NewDelimiterConfig(template).ParseAndCleanup()
+	if err != nil {
+		return nil, err
+	}
+	tmpl = tmpl.Delims(delims.Start, delims.End)
+
 	for _, fm := range t.funcMaps {
 		tmpl.Funcs(fm)
 	}
 
 	tmpl.Option("missingkey=" + t.missingKeyOption)
-	_, err := tmpl.Parse(template)
+	_, err = tmpl.Parse(template)
 	if err != nil {
 		return nil, TemplateErrorBuilder(err).WithSource(&template).WithInput(input, t.templateInputFormatter).Build()
 	}