/
kubernetes.go
133 lines (119 loc) · 3.53 KB
/
kubernetes.go
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// Licensed to Apache Software Foundation (ASF) under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Apache Software Foundation (ASF) licenses this file to you under
// the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
package kubernetes
import (
"bufio"
"bytes"
"errors"
"fmt"
"strings"
"text/template"
"unicode"
"github.com/Masterminds/sprig/v3"
jsonpatch "github.com/evanphx/json-patch"
"github.com/ghodss/yaml"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/runtime"
)
var ErrNothingLoaded = errors.New("LoadTemplate: failed load anything from manifests")
// ApplyOverlay applies an overlay using JSON patch strategy over the current Object in place.
func ApplyOverlay(current, overlay runtime.Object) error {
cj, err := runtime.Encode(unstructured.UnstructuredJSONScheme, current)
if err != nil {
return err
}
uj, err := runtime.Encode(unstructured.UnstructuredJSONScheme, overlay)
if err != nil {
return err
}
merged, err := jsonpatch.MergePatch(cj, uj)
if err != nil {
return err
}
return runtime.DecodeInto(unstructured.UnstructuredJSONScheme, merged, current)
}
// LoadTemplate loads a YAML file to a component
func LoadTemplate(manifest string, values interface{}, funcMap template.FuncMap, spec interface{}) ([]byte, error) {
bb, err := GenerateManifests(manifest, values, funcMap)
if err != nil {
return nil, err
}
return bb, yaml.Unmarshal(bb, spec)
}
// GenerateManifests generate manifests from templates, CR and values
func GenerateManifests(manifest string, values interface{}, funcMap template.FuncMap) ([]byte, error) {
tmplBuilder := template.New("manifest").
Funcs(template.FuncMap{
"toYAML": toYAML,
}).
Funcs(sprig.TxtFuncMap())
if funcMap != nil {
tmplBuilder = tmplBuilder.Funcs(funcMap)
}
tmpl, err := tmplBuilder.Parse(manifest)
if err != nil {
return nil, err
}
buf := bytes.Buffer{}
err = tmpl.Execute(&buf, values)
if err != nil {
return nil, err
}
bb := stripCharacters(buf.Bytes())
if len(bb) < 1 {
return nil, ErrNothingLoaded
}
return bb, nil
}
func toYAML(v interface{}) string {
b, _ := yaml.Marshal(v)
return string(b)
}
func stripCharacters(bb []byte) []byte {
s := string(bb)
s = strings.TrimSpace(s)
s = stripComment(s)
s = strings.TrimSpace(s)
return []byte(s)
}
const commentChars = "#"
func stripComment(source string) string {
sc := bufio.NewScanner(strings.NewReader(source))
ll := make([]string, 0)
for sc.Scan() {
l := sc.Text()
if cut := strings.IndexAny(l, commentChars); cut >= 0 {
l = strings.TrimRightFunc(l[:cut], unicode.IsSpace)
}
if strings.TrimSpace(l) != "" {
ll = append(ll, l)
}
}
return strings.Join(ll, "\n")
}
type ErrorCollector []error
func (c *ErrorCollector) Collect(e error) { *c = append(*c, e) }
func (c *ErrorCollector) Error() error {
if len(*c) < 1 {
return nil
}
err := "Collected errors:\n"
for i, e := range *c {
err += fmt.Sprintf("\tError %d: %s\n", i, e.Error())
}
return fmt.Errorf(err)
}