// Copyright 2024 Stefan Prodan.
// SPDX-License-Identifier: AGPL-3.0
package builder
import (
"bytes"
"fmt"
"strings"
"text/template"
ssautil "github.com/fluxcd/pkg/ssa/utils"
sprig "github.com/go-task/slim-sprig/v3"
"github.com/gosimple/slug"
apix "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"sigs.k8s.io/yaml"
fluxcdv1 "github.com/controlplaneio-fluxcd/flux-operator/api/v1"
"github.com/controlplaneio-fluxcd/flux-operator/internal/inputs"
)
// BuildResourceSet builds a list of Kubernetes resources
// from a YAML template, a list of JSON templates and the
// given combined inputs.
func BuildResourceSet(yamlTemplate string, templates []*apix.JSON, combinedInputs inputs.Combined) ([]*unstructured.Unstructured, error) {
var objects []*unstructured.Unstructured
// build resources from JSON templates
for i, tmpl := range templates {
if len(combinedInputs) == 0 {
object, err := BuildResource(tmpl, nil)
if err != nil {
return nil, fmt.Errorf("failed to build resource: %w", err)
}
objects = append(objects, object)
continue
}
for _, input := range combinedInputs {
object, err := BuildResource(tmpl, input)
if err != nil {
return nil, fmt.Errorf("failed to build resources[%d]: %w", i, err)
}
// exclude object based on annotations
if val := object.GetAnnotations()[fluxcdv1.ReconcileAnnotation]; val == fluxcdv1.DisabledValue {
continue
}
// deduplicate objects
if !containsObject(objects, object) {
objects = append(objects, object)
}
}
}
// build resources from multi-doc YAML template
if yamlTemplate != "" {
var objectsFromTemplate []*unstructured.Unstructured
if len(combinedInputs) == 0 {
objs, err := BuildResourcesFromYAML(yamlTemplate, nil)
if err != nil {
return nil, fmt.Errorf("failed to build resource: %w", err)
}
objectsFromTemplate = append(objectsFromTemplate, objs...)
}
for _, input := range combinedInputs {
objs, err := BuildResourcesFromYAML(yamlTemplate, input)
if err != nil {
return nil, fmt.Errorf("failed to build resources: %w", err)
}
objectsFromTemplate = append(objectsFromTemplate, objs...)
}
for _, object := range objectsFromTemplate {
// exclude object based on annotations
if val := object.GetAnnotations()[fluxcdv1.ReconcileAnnotation]; val == fluxcdv1.DisabledValue {
continue
}
// deduplicate objects
if !containsObject(objects, object) {
objects = append(objects, object)
}
}
}
return objects, nil
}
// BuildResource builds a Kubernetes resource from a JSON template using the provided inputs.
// Template functions are provided by the slim-sprig library https://go-task.github.io/slim-sprig/.
// In addition, the slugify function is available to generate slugs from strings using https://github.com/gosimple/slug/.
// And for readability, a toYaml function is available to encode an input value into a YAML string.
func BuildResource(tmpl *apix.JSON, inputSet map[string]any) (*unstructured.Unstructured, error) {
yamlTemplate, err := yaml.JSONToYAML(tmpl.Raw)
if err != nil {
return nil, fmt.Errorf("failed to convert template to YAML: %w", err)
}
tp, err := newTemplate(string(yamlTemplate), inputSet)
if err != nil {
return nil, fmt.Errorf("failed to parse template: %w", err)
}
b := &strings.Builder{}
err = tp.Execute(b, nil)
if err != nil {
return nil, fmt.Errorf("failed to execute template: %w", err)
}
object, err := ssautil.ReadObject(bytes.NewReader([]byte(b.String())))
if err != nil {
return nil, fmt.Errorf("failed to read object: %w", err)
}
return object, nil
}
// BuildResourcesFromYAML builds a list of Kubernetes resources from a multi-doc YAML template
// using the same templating functions as BuildResource.
func BuildResourcesFromYAML(yamlTemplate string, inputSet map[string]any) ([]*unstructured.Unstructured, error) {
tp, err := newTemplate(yamlTemplate, inputSet)
if err != nil {
return nil, fmt.Errorf("failed to parse multi-doc YAML template: %w", err)
}
b := &strings.Builder{}
err = tp.Execute(b, nil)
if err != nil {
return nil, fmt.Errorf("failed to execute multi-doc YAML template: %w", err)
}
objects, err := ssautil.ReadObjects(bytes.NewReader([]byte(b.String())))
if err != nil {
return nil, fmt.Errorf("failed to read objects from multi-doc YAML: %w", err)
}
return objects, nil
}
func newTemplate(yamlTemplate string, inputSet map[string]any) (*template.Template, error) {
tp, err := template.New("resourceset").
Delims("<<", ">>").
Funcs(sprig.HermeticTxtFuncMap()).
Funcs(template.FuncMap{"slugify": slug.Make}).
Funcs(template.FuncMap{"inputs": func() any { return inputSet }}).
Funcs(template.FuncMap{"toYaml": toYaml, "mustToYaml": mustToYaml}).
Option("missingkey=error").
Parse(yamlTemplate)
if err != nil {
return nil, err
}
return tp, nil
}
func containsObject(objects []*unstructured.Unstructured, object *unstructured.Unstructured) bool {
found := false
for _, obj := range objects {
if obj.GetAPIVersion() == object.GetAPIVersion() &&
obj.GetKind() == object.GetKind() &&
obj.GetNamespace() == object.GetNamespace() &&
obj.GetName() == object.GetName() {
found = true
break
}
}
return found
}
// init initializes the slugify Go template function with the default settings.
func init() {
// set max length to 63 characters which is
// the maximum length for a Kubernetes label value
slug.MaxLength = 63
// enable smart truncate to avoid cutting words in half
slug.EnableSmartTruncate = true
}
// toYaml encodes an item into a YAML string.
// On error, it returns an empty string.
func toYaml(v any) string {
if b, err := mustToYaml(v); err == nil {
return b
}
return ""
}
// mustToYaml encodes an item into a YAML string.
// On error, it returns an empty string and the error.
func mustToYaml(v any) (string, error) {
b, err := yaml.Marshal(v)
if err != nil {
return "", err
}
return string(b), nil
}
