mirror of https://github.com/kubernetes/kops.git
111 lines
2.9 KiB
Go
111 lines
2.9 KiB
Go
/*
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Copyright 2019 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package templater
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import (
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"bytes"
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"fmt"
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"strings"
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"text/template"
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"k8s.io/kops/pkg/apis/kops"
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)
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const (
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templateName = "mainTemplate"
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)
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// Templater is golang template renders
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type Templater struct {
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channel *kops.Channel
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}
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// NewTemplater returns a new renderer implementation
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func NewTemplater(channel *kops.Channel) *Templater {
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return &Templater{
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channel: channel,
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}
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}
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// Render is responsible for actually rendering the template
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func (r *Templater) Render(content string, context map[string]interface{}, snippets map[string]string, failOnMissing bool) (rendered string, err error) {
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// @step: create the template
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tm := template.New(templateName)
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if _, err = tm.Funcs(r.templateFuncsMap(tm)).Parse(content); err != nil {
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return
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}
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if failOnMissing {
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tm.Option("missingkey=error")
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}
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// @step: add the snippits into the mix
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for filename, snippet := range snippets {
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if filename == templateName {
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return "", fmt.Errorf("snippet cannot have the same name as the template: %s", filename)
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}
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if _, err = tm.New(filename).Parse(snippet); err != nil {
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return rendered, fmt.Errorf("unable to parse snippet: %s, error: %s", filename, err)
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}
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}
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// @step: render the actual template
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writer := new(bytes.Buffer)
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defer func() {
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if r := recover(); r != nil {
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err = fmt.Errorf("failed to parse template, error: %s", r)
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}
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}()
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if err = tm.ExecuteTemplate(writer, templateName, context); err != nil {
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return
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}
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return writer.String(), nil
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}
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// indentContent is responsible for indenting the string content
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func indentContent(indent int, content string) string {
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var b bytes.Buffer
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length := len(strings.Split(content, "\n")) - 1
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for i, x := range strings.Split(content, "\n") {
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// @check if the length of the line is zero and set spacer
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spacer := indent
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if i == 0 || len(x) <= 0 {
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spacer = 0
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}
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// @step: write the line to the buffer
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line := fmt.Sprintf("%"+fmt.Sprintf("%d", spacer)+"s%s", "", x)
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b.WriteString(line)
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// @check if we need a newline
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if i < length {
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b.WriteString("\n")
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}
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}
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return b.String()
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}
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// includeSnippet is responsible for including a snippet
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func includeSnippet(tm *template.Template, name string, context map[string]interface{}) (string, error) {
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b := bytes.NewBufferString("")
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if err := tm.ExecuteTemplate(b, name, context); err != nil {
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return "", fmt.Errorf("snippet: %s, issue: %s", name, err)
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}
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return b.String(), nil
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}
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