terraform/builtin/providers/template/resource_template_dir.go

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package template
import (
"archive/tar"
"bytes"
"crypto/sha1"
"encoding/hex"
"fmt"
"io"
"io/ioutil"
"os"
"path"
"path/filepath"
"github.com/hashicorp/terraform/helper/pathorcontents"
"github.com/hashicorp/terraform/helper/schema"
)
func resourceDir() *schema.Resource {
return &schema.Resource{
Create: resourceTemplateDirCreate,
Read: resourceTemplateDirRead,
Delete: resourceTemplateDirDelete,
Schema: map[string]*schema.Schema{
"source_dir": {
Type: schema.TypeString,
Description: "Path to the directory where the files to template reside",
Required: true,
ForceNew: true,
},
"vars": {
Type: schema.TypeMap,
Optional: true,
Default: make(map[string]interface{}),
Description: "Variables to substitute",
ValidateFunc: validateVarsAttribute,
ForceNew: true,
},
"destination_dir": {
Type: schema.TypeString,
Description: "Path to the directory where the templated files will be written",
Required: true,
ForceNew: true,
},
},
}
}
func resourceTemplateDirRead(d *schema.ResourceData, meta interface{}) error {
sourceDir := d.Get("source_dir").(string)
destinationDir := d.Get("destination_dir").(string)
// If the output doesn't exist, mark the resource for creation.
if _, err := os.Stat(destinationDir); os.IsNotExist(err) {
d.SetId("")
return nil
}
// If the combined hash of the input and output directories is different from
// the stored one, mark the resource for re-creation.
//
// The output directory is technically enough for the general case, but by
// hashing the input directory as well, we make development much easier: when
// a developer modifies one of the input files, the generation is
// re-triggered.
hash, err := generateID(sourceDir, destinationDir)
if err != nil {
return err
}
if hash != d.Id() {
d.SetId("")
return nil
}
return nil
}
func resourceTemplateDirCreate(d *schema.ResourceData, meta interface{}) error {
sourceDir := d.Get("source_dir").(string)
destinationDir := d.Get("destination_dir").(string)
vars := d.Get("vars").(map[string]interface{})
// Always delete the output first, otherwise files that got deleted from the
// input directory might still be present in the output afterwards.
if err := resourceTemplateDirDelete(d, meta); err != nil {
return err
}
// Create the destination directory and any other intermediate directories
// leading to it.
if _, err := os.Stat(destinationDir); err != nil {
if err := os.MkdirAll(destinationDir, 0777); err != nil {
return err
}
}
// Recursively crawl the input files/directories and generate the output ones.
err := filepath.Walk(sourceDir, func(p string, f os.FileInfo, err error) error {
if err != nil {
return err
}
if f.IsDir() {
return nil
}
relPath, _ := filepath.Rel(sourceDir, p)
return generateDirFile(p, path.Join(destinationDir, relPath), f, vars)
})
if err != nil {
return err
}
// Compute ID.
hash, err := generateID(sourceDir, destinationDir)
if err != nil {
return err
}
d.SetId(hash)
return nil
}
func resourceTemplateDirDelete(d *schema.ResourceData, _ interface{}) error {
d.SetId("")
destinationDir := d.Get("destination_dir").(string)
if _, err := os.Stat(destinationDir); os.IsNotExist(err) {
return nil
}
if err := os.RemoveAll(destinationDir); err != nil {
return fmt.Errorf("could not delete directory %q: %s", destinationDir, err)
}
return nil
}
func generateDirFile(sourceDir, destinationDir string, f os.FileInfo, vars map[string]interface{}) error {
inputContent, _, err := pathorcontents.Read(sourceDir)
if err != nil {
return err
}
outputContent, err := execute(inputContent, vars)
if err != nil {
return templateRenderError(fmt.Errorf("failed to render %v: %v", sourceDir, err))
}
outputDir := path.Dir(destinationDir)
if _, err := os.Stat(outputDir); err != nil {
if err := os.MkdirAll(outputDir, 0777); err != nil {
return err
}
}
err = ioutil.WriteFile(destinationDir, []byte(outputContent), f.Mode())
if err != nil {
return err
}
return nil
}
func generateID(sourceDir, destinationDir string) (string, error) {
inputHash, err := generateDirHash(sourceDir)
if err != nil {
return "", err
}
outputHash, err := generateDirHash(destinationDir)
if err != nil {
return "", err
}
checksum := sha1.Sum([]byte(inputHash + outputHash))
return hex.EncodeToString(checksum[:]), nil
}
func generateDirHash(directoryPath string) (string, error) {
tarData, err := tarDir(directoryPath)
if err != nil {
return "", fmt.Errorf("could not generate output checksum: %s", err)
}
checksum := sha1.Sum(tarData)
return hex.EncodeToString(checksum[:]), nil
}
func tarDir(directoryPath string) ([]byte, error) {
buf := new(bytes.Buffer)
tw := tar.NewWriter(buf)
writeFile := func(p string, f os.FileInfo, err error) error {
if err != nil {
return err
}
var header *tar.Header
var file *os.File
header, err = tar.FileInfoHeader(f, f.Name())
if err != nil {
return err
}
relPath, _ := filepath.Rel(directoryPath, p)
header.Name = relPath
if err := tw.WriteHeader(header); err != nil {
return err
}
if f.IsDir() {
return nil
}
file, err = os.Open(p)
if err != nil {
return err
}
defer file.Close()
_, err = io.Copy(tw, file)
return err
}
if err := filepath.Walk(directoryPath, writeFile); err != nil {
return []byte{}, err
}
if err := tw.Flush(); err != nil {
return []byte{}, err
}
return buf.Bytes(), nil
}