portainer/pkg/libstack/compose/bind_mount_hash.go

150 lines
3.4 KiB
Go

package compose
import (
"crypto/sha256"
"encoding/hex"
"io"
"os"
"path/filepath"
"sort"
"github.com/compose-spec/compose-go/v2/types"
"github.com/rs/zerolog/log"
)
const BindMountHashLabelKey = "io.portainer.bind-mount-hash"
func addBindMountHashLabel(name string, s types.ServiceConfig) (types.ServiceConfig, error) {
hashes := []string{}
for _, volume := range s.Volumes {
// Calculate hash for bind mounts only for now
if volume.Type != "bind" {
continue
}
// Calculate hash for volume.Source, volume.Source can be a file or dir
// and volume.Source is already an absolute path so we can hash it directly
hash, err := pathHash(volume.Source)
if err != nil {
// If we fail to calculate the hash for this bind mount, skip it and continue
log.Debug().Err(err).
Str("bind_mount_source", volume.Source).
Str("service", name).
Msg("failed to calculate hash for bind mount, skipping this bind mount from hash label calculation")
continue
}
if hash != "" {
hashes = append(hashes, hash)
}
}
if len(hashes) == 0 {
return s, nil
}
// Sort hashes to ensure deterministic output
sort.Strings(hashes)
// Final hash of the combined hashes
finalH := sha256.New()
for _, h := range hashes {
finalH.Write([]byte(h))
}
value := hex.EncodeToString(finalH.Sum(nil))
if s.Labels == nil {
s.Labels = make(map[string]string)
}
s.Labels[BindMountHashLabelKey] = value
log.Debug().Str("service", name).
Str("label_key", BindMountHashLabelKey).
Str("bind_mount_hash", value).
Msg("Calculated bind mount hash for service")
return s, nil
}
// pathHash calculates a SHA-256 hash for a file or a directory.
func pathHash(path string) (string, error) {
hash := sha256.New()
info, err := os.Stat(path)
if err != nil {
return "", err
}
if !info.IsDir() {
// It's a single file
return hashFile(path)
}
// It's a directory: we must collect and sort all files for determinism
var files []string
if err := filepath.Walk(path, func(p string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if !info.IsDir() {
files = append(files, p)
}
return nil
}); err != nil {
return "", err
}
sort.Strings(files)
for _, f := range files {
// Include the relative path in the hash so that renames and moves within
// the directory change the hash even when file contents stay the same.
relPath, err := filepath.Rel(path, f)
if err != nil {
return "", err
}
if _, err := hash.Write([]byte(relPath)); err != nil {
return "", err
}
// Stream the file content into the same hasher
if err := copyFileToHash(hash, f); err != nil {
return "", err
}
}
return hex.EncodeToString(hash.Sum(nil)), nil
}
func hashFile(path string) (string, error) {
h := sha256.New()
if err := copyFileToHash(h, path); err != nil {
return "", err
}
return hex.EncodeToString(h.Sum(nil)), nil
}
// copyFileToHash opens the file at path, streams its content into w, and closes it.
// If the copy fails, the close error is logged but the copy error is returned.
// If the copy succeeds but close fails, the close error is returned.
func copyFileToHash(w io.Writer, path string) (err error) {
f, err := os.Open(path)
if err != nil {
return err
}
defer func() {
if cerr := f.Close(); cerr != nil {
log.Debug().Err(cerr).
Str("filename", path).
Msg("error closing file after hash")
if err == nil {
err = cerr
}
}
}()
_, err = io.Copy(w, f)
return err
}