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// Copyright (C) 2016-2017 Vincent Ambo <mail@tazj.in>
//
// This file is part of Kontemplate.
//
// Kontemplate is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
package templater
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path"
"strings"
"text/template"
"github.com/Masterminds/sprig"
"github.com/polydawn/meep"
"github.com/tazjin/kontemplate/context"
"github.com/tazjin/kontemplate/util"
)
const failOnMissingKeys string = "missingkey=error"
// Error that is caused by non-existent template files being specified
type TemplateNotFoundError struct {
meep.AllTraits
Name string
Path string
}
// Error that is caused during templating, e.g. required value being absent or invalid template format
type TemplatingError struct {
meep.TraitAutodescribing
meep.TraitCausable
}
type RenderedResource struct {
Filename string
Rendered string
}
type RenderedResourceSet struct {
Name string
Resources []RenderedResource
}
func LoadAndApplyTemplates(include *[]string, exclude *[]string, c *context.Context) ([]RenderedResourceSet, error) {
limitedResourceSets := applyLimits(&c.ResourceSets, include, exclude)
renderedResourceSets := make([]RenderedResourceSet, 0)
if len(*limitedResourceSets) == 0 {
return renderedResourceSets, fmt.Errorf("No valid resource sets included!")
}
for _, rs := range *limitedResourceSets {
set, err := processResourceSet(c, &rs)
if err != nil {
return nil, err
}
renderedResourceSets = append(renderedResourceSets, *set)
}
return renderedResourceSets, nil
}
func processResourceSet(c *context.Context, rs *context.ResourceSet) (*RenderedResourceSet, error) {
fmt.Fprintf(os.Stderr, "Loading resources for %s\n", rs.Name)
rp := path.Join(c.BaseDir, rs.Path)
// Explicitly discard this error, which will give us an empty list of files instead.
// This will end up printing a warning to the user, but it won't stop the rest of the process.
files, _ := ioutil.ReadDir(rp)
resources, err := processFiles(c, rs, rp, files)
if err != nil {
return nil, meep.New(
&TemplateNotFoundError{Name: rs.Name, Path: rs.Path},
meep.Cause(err),
)
}
return &RenderedResourceSet{
Name: rs.Name,
Resources: resources,
}, nil
}
func processFiles(c *context.Context, rs *context.ResourceSet, rp string, files []os.FileInfo) ([]RenderedResource, error) {
resources := make([]RenderedResource, 0)
for _, file := range files {
if !file.IsDir() && isResourceFile(file) {
p := path.Join(rp, file.Name())
o, err := templateFile(c, rs, p)
if err != nil {
return resources, err
}
res := RenderedResource{
Filename: file.Name(),
Rendered: o,
}
resources = append(resources, res)
}
}
return resources, nil
}
func templateFile(c *context.Context, rs *context.ResourceSet, filename string) (string, error) {
tpl, err := template.New(path.Base(filename)).Funcs(templateFuncs(rs)).Option(failOnMissingKeys).ParseFiles(filename)
if err != nil {
return "", meep.New(
&TemplateNotFoundError{Name: filename},
meep.Cause(err),
)
}
var b bytes.Buffer
rs.Values = *util.Merge(&c.Global, &rs.Values)
err = tpl.Execute(&b, rs.Values)
if err != nil {
return "", meep.New(
&TemplatingError{},
meep.Cause(err),
)
}
return b.String(), nil
}
// Applies the limits of explicitly included or excluded resources and returns the updated resource set.
// Exclude takes priority over include
func applyLimits(rs *[]context.ResourceSet, include *[]string, exclude *[]string) *[]context.ResourceSet {
if len(*include) == 0 && len(*exclude) == 0 {
return rs
}
// Exclude excluded resource sets
excluded := make([]context.ResourceSet, 0)
for _, r := range *rs {
if !matchesResourceSet(exclude, &r) {
excluded = append(excluded, r)
}
}
// Include included resource sets
if len(*include) == 0 {
return &excluded
}
included := make([]context.ResourceSet, 0)
for _, r := range excluded {
if matchesResourceSet(include, &r) {
included = append(included, r)
}
}
return &included
}
// Check whether an include/exclude string slice matches a resource set
func matchesResourceSet(s *[]string, rs *context.ResourceSet) bool {
for _, r := range *s {
r = strings.TrimSuffix(r, "/")
if r == rs.Name || r == rs.Parent {
return true
}
}
return false
}
func templateFuncs(rs *context.ResourceSet) template.FuncMap {
m := sprig.TxtFuncMap()
m["json"] = func(data interface{}) string {
b, _ := json.Marshal(data)
return string(b)
}
m["passLookup"] = GetFromPass
m["lookupIPAddr"] = GetIPsFromDNS
m["insertFile"] = func(file string) (string, error) {
data, err := ioutil.ReadFile(path.Join(rs.Path, file))
if err != nil {
return "", err
}
return string(data), nil
}
return m
}
// Checks whether a file is a resource file (i.e. is YAML or JSON) and not a default values file.
func isResourceFile(f os.FileInfo) bool {
for _, defaultFile := range util.DefaultFilenames {
if f.Name() == defaultFile {
return false
}
}
return strings.HasSuffix(f.Name(), "yaml") ||
strings.HasSuffix(f.Name(), "yml") ||
strings.HasSuffix(f.Name(), "json")
}
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