kustomize-controller/controllers/kustomization_varsub.go

110 lines
3.1 KiB
Go

package controllers
import (
"context"
"fmt"
"regexp"
"strings"
"github.com/drone/envsubst"
corev1 "k8s.io/api/core/v1"
apierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/types"
"sigs.k8s.io/controller-runtime/pkg/client"
"sigs.k8s.io/kustomize/api/resource"
"sigs.k8s.io/yaml"
kustomizev1 "github.com/fluxcd/kustomize-controller/api/v1beta2"
)
// varsubRegex is the regular expression used to validate
// the var names before substitution
const varsubRegex = "^[_[:alpha:]][_[:alpha:][:digit:]]*$"
// substituteVariables replaces the vars with their values in the specified resource.
// If a resource is labeled or annotated with
// 'kustomize.toolkit.fluxcd.io/substitute: disabled' the substitution is skipped.
func substituteVariables(
ctx context.Context,
kubeClient client.Client,
kustomization kustomizev1.Kustomization,
res *resource.Resource) (*resource.Resource, error) {
resData, err := res.AsYAML()
if err != nil {
return nil, err
}
key := fmt.Sprintf("%s/substitute", kustomizev1.GroupVersion.Group)
if res.GetLabels()[key] == kustomizev1.DisabledValue || res.GetAnnotations()[key] == kustomizev1.DisabledValue {
return nil, nil
}
vars := make(map[string]string)
// load vars from ConfigMaps and Secrets data keys
for _, reference := range kustomization.Spec.PostBuild.SubstituteFrom {
namespacedName := types.NamespacedName{Namespace: kustomization.Namespace, Name: reference.Name}
switch reference.Kind {
case "ConfigMap":
resource := &corev1.ConfigMap{}
if err := kubeClient.Get(ctx, namespacedName, resource); err != nil {
if reference.Optional && apierrors.IsNotFound(err) {
continue
}
return nil, fmt.Errorf("substitute from 'ConfigMap/%s' error: %w", reference.Name, err)
}
for k, v := range resource.Data {
vars[k] = strings.ReplaceAll(v, "\n", "")
}
case "Secret":
resource := &corev1.Secret{}
if err := kubeClient.Get(ctx, namespacedName, resource); err != nil {
if reference.Optional && apierrors.IsNotFound(err) {
continue
}
return nil, fmt.Errorf("substitute from 'Secret/%s' error: %w", reference.Name, err)
}
for k, v := range resource.Data {
vars[k] = strings.ReplaceAll(string(v), "\n", "")
}
}
}
// load in-line vars (overrides the ones from resources)
if kustomization.Spec.PostBuild.Substitute != nil {
for k, v := range kustomization.Spec.PostBuild.Substitute {
vars[k] = strings.ReplaceAll(v, "\n", "")
}
}
// run bash variable substitutions
if len(vars) > 0 {
r, _ := regexp.Compile(varsubRegex)
for v := range vars {
if !r.MatchString(v) {
return nil, fmt.Errorf("'%s' var name is invalid, must match '%s'", v, varsubRegex)
}
}
output, err := envsubst.Eval(string(resData), func(s string) string {
return vars[s]
})
if err != nil {
return nil, fmt.Errorf("variable substitution failed: %w", err)
}
jsonData, err := yaml.YAMLToJSON([]byte(output))
if err != nil {
return nil, fmt.Errorf("YAMLToJSON: %w", err)
}
err = res.UnmarshalJSON(jsonData)
if err != nil {
return nil, fmt.Errorf("UnmarshalJSON: %w", err)
}
}
return res, nil
}