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Refactor handling of runtime configuration to prepare for reloading

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This commit is contained in:
Frederik Ring 2024-02-13 19:21:57 +01:00
parent c4e480dcfd
commit 83fa0aae48
14 changed files with 665 additions and 520 deletions
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155
cmd/backup/command.go Normal file
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@ -0,0 +1,155 @@
// Copyright 2024 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import (
"fmt"
"log/slog"
"os"
"os/signal"
"syscall"
"github.com/robfig/cron/v3"
)
type command struct {
logger *slog.Logger
schedules []cron.EntryID
cr *cron.Cron
reload chan struct{}
}
func newCommand() *command {
return &command{
logger: slog.New(slog.NewTextHandler(os.Stdout, nil)),
}
}
// runAsCommand executes a backup run for each configuration that is available
// and then returns
func (c *command) runAsCommand() error {
configurations, err := sourceConfiguration(configStrategyEnv)
if err != nil {
return fmt.Errorf("runAsCommand: error loading env vars: %w", err)
}
for _, config := range configurations {
if err := runScript(config); err != nil {
return fmt.Errorf("runAsCommand: error running script: %w", err)
}
}
return nil
}
type foregroundOpts struct {
profileCronExpression string
}
// runInForeground starts the program as a long running process, scheduling
// a job for each configuration that is available.
func (c *command) runInForeground(opts foregroundOpts) error {
c.cr = cron.New(
cron.WithParser(
cron.NewParser(
cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor,
),
),
)
if err := c.schedule(configStrategyConfd); err != nil {
return fmt.Errorf("runInForeground: error scheduling: %w", err)
}
if opts.profileCronExpression != "" {
if _, err := c.cr.AddFunc(opts.profileCronExpression, c.profile); err != nil {
return fmt.Errorf("runInForeground: error adding profiling job: %w", err)
}
}
var quit = make(chan os.Signal, 1)
c.reload = make(chan struct{}, 1)
signal.Notify(quit, syscall.SIGTERM, syscall.SIGINT)
c.cr.Start()
for {
select {
case <-quit:
ctx := c.cr.Stop()
<-ctx.Done()
return nil
case <-c.reload:
if err := c.schedule(configStrategyConfd); err != nil {
return fmt.Errorf("runInForeground: error reloading configuration: %w", err)
}
}
}
}
// schedule wipes all existing schedules and enqueues all schedules available
// using the given configuration strategy
func (c *command) schedule(strategy configStrategy) error {
for _, id := range c.schedules {
c.cr.Remove(id)
}
configurations, err := sourceConfiguration(strategy)
if err != nil {
return fmt.Errorf("schedule: error sourcing configuration: %w", err)
}
for _, cfg := range configurations {
config := cfg
id, err := c.cr.AddFunc(config.BackupCronExpression, func() {
c.logger.Info(
fmt.Sprintf(
"Now running script on schedule %s",
config.BackupCronExpression,
),
)
if err := runScript(config); err != nil {
c.logger.Error(
fmt.Sprintf(
"Unexpected error running schedule %s: %v",
config.BackupCronExpression,
err,
),
"error",
err,
)
}
})
if err != nil {
return fmt.Errorf("addJob: error adding schedule %s: %w", config.BackupCronExpression, err)
}
c.logger.Info(fmt.Sprintf("Successfully scheduled backup %s with expression %s", config.source, config.BackupCronExpression))
if ok := checkCronSchedule(config.BackupCronExpression); !ok {
c.logger.Warn(
fmt.Sprintf("Scheduled cron expression %s will never run, is this intentional?", config.BackupCronExpression),
)
if err != nil {
return fmt.Errorf("schedule: error scheduling: %w", err)
}
c.schedules = append(c.schedules, id)
}
}
return nil
}
// must exits the program when passed an error. It should be the only
// place where the application exits forcefully.
func (c *command) must(err error) {
if err != nil {
c.logger.Error(
fmt.Sprintf("Fatal error running command: %v", err),
"error",
err,
)
os.Exit(1)
}
}

39
cmd/backup/config.go
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@ -80,6 +80,8 @@ type Config struct {
DropboxAppSecret string `split_words:"true"`
DropboxRemotePath string `split_words:"true"`
DropboxConcurrencyLevel NaturalNumber `split_words:"true" default:"6"`
source string
additionalEnvVars map[string]string
}
type CompressionType string
@ -172,3 +174,40 @@ func (n *WholeNumber) Decode(v string) error {
func (n *WholeNumber) Int() int {
return int(*n)
}
type envVarLookup struct {
ok bool
key string
value string
}
// applyEnv sets the values in `additionalEnvVars` as environment variables.
// It returns a function that reverts all values that have been set to its
// previous state.
func (c *Config) applyEnv() (func() error, error) {
lookups := []envVarLookup{}
unset := func() error {
for _, lookup := range lookups {
if !lookup.ok {
if err := os.Unsetenv(lookup.key); err != nil {
return fmt.Errorf("(*Config).applyEnv: error unsetting env var %s: %w", lookup.key, err)
}
continue
}
if err := os.Setenv(lookup.key, lookup.value); err != nil {
return fmt.Errorf("(*Config).applyEnv: error setting back env var %s: %w", lookup.key, err)
}
}
return nil
}
for key, value := range c.additionalEnvVars {
current, ok := os.LookupEnv(key)
lookups = append(lookups, envVarLookup{ok: ok, key: key, value: current})
if err := os.Setenv(key, value); err != nil {
return unset, fmt.Errorf("(*Config).applyEnv: error setting env var: %w", err)
}
}
return unset, nil
}

55
cmd/backup/config_provider.go
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@ -12,9 +12,39 @@ import (
"github.com/offen/envconfig"
)
type configStrategy string
const (
configStrategyEnv configStrategy = "env"
configStrategyConfd configStrategy = "confd"
)
// sourceConfiguration returns a list of config objects using the given
// strategy. It should be the single entrypoint for retrieving configuration
// for all consumers.
func sourceConfiguration(strategy configStrategy) ([]*Config, error) {
switch strategy {
case configStrategyEnv:
c, err := loadConfigFromEnvVars()
return []*Config{c}, err
case configStrategyConfd:
cs, err := loadConfigsFromEnvFiles("/etc/dockervolumebackup/conf.d")
if err != nil {
if os.IsNotExist(err) {
return sourceConfiguration(configStrategyEnv)
}
return nil, fmt.Errorf("sourceConfiguration: error loading config files: %w", err)
}
return cs, nil
default:
return nil, fmt.Errorf("sourceConfiguration: received unknown config strategy: %v", strategy)
}
}
// envProxy is a function that mimics os.LookupEnv but can read values from any other source
type envProxy func(string) (string, bool)
// loadConfig creates a config object using the given lookup function
func loadConfig(lookup envProxy) (*Config, error) {
envconfig.Lookup = func(key string) (string, bool) {
value, okValue := lookup(key)
@ -44,17 +74,16 @@ func loadConfig(lookup envProxy) (*Config, error) {
return c, nil
}
func loadEnvVars() (*Config, error) {
return loadConfig(os.LookupEnv)
func loadConfigFromEnvVars() (*Config, error) {
c, err := loadConfig(os.LookupEnv)
if err != nil {
return nil, fmt.Errorf("loadEnvVars: error loading config from environment: %w", err)
}
c.source = "from environment"
return c, nil
}
type configFile struct {
name string
config *Config
additionalEnvVars map[string]string
}
func loadEnvFiles(directory string) ([]configFile, error) {
func loadConfigsFromEnvFiles(directory string) ([]*Config, error) {
items, err := os.ReadDir(directory)
if err != nil {
if os.IsNotExist(err) {
@ -63,7 +92,7 @@ func loadEnvFiles(directory string) ([]configFile, error) {
return nil, fmt.Errorf("loadEnvFiles: failed to read files from env directory: %w", err)
}
cs := []configFile{}
configs := []*Config{}
for _, item := range items {
if item.IsDir() {
continue
@ -88,8 +117,10 @@ func loadEnvFiles(directory string) ([]configFile, error) {
if err != nil {
return nil, fmt.Errorf("loadEnvFiles: error loading config from file %s: %w", p, err)
}
cs = append(cs, configFile{config: c, name: item.Name(), additionalEnvVars: envFile})
c.source = item.Name()
c.additionalEnvVars = envFile
configs = append(configs, c)
}
return cs, nil
return configs, nil
}

41
cmd/backup/copy_archive.go Normal file
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@ -0,0 +1,41 @@
// Copyright 2024 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import (
"fmt"
"os"
"path"
"golang.org/x/sync/errgroup"
)
// copyArchive makes sure the backup file is copied to both local and remote locations
// as per the given configuration.
func (s *script) copyArchive() error {
_, name := path.Split(s.file)
if stat, err := os.Stat(s.file); err != nil {
return fmt.Errorf("copyArchive: unable to stat backup file: %w", err)
} else {
size := stat.Size()
s.stats.BackupFile = BackupFileStats{
Size: uint64(size),
Name: name,
FullPath: s.file,
}
}
eg := errgroup.Group{}
for _, backend := range s.storages {
b := backend
eg.Go(func() error {
return b.Copy(s.file)
})
}
if err := eg.Wait(); err != nil {
return fmt.Errorf("copyArchive: error copying archive: %w", err)
}
return nil
}

87
cmd/backup/create_archive.go Normal file
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@ -0,0 +1,87 @@
// Copyright 2024 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import (
"fmt"
"io/fs"
"path/filepath"
"github.com/otiai10/copy"
)
// createArchive creates a tar archive of the configured backup location and
// saves it to disk.
func (s *script) createArchive() error {
backupSources := s.c.BackupSources
if s.c.BackupFromSnapshot {
s.logger.Warn(
"Using BACKUP_FROM_SNAPSHOT has been deprecated and will be removed in the next major version.",
)
s.logger.Warn(
"Please use `archive-pre` and `archive-post` commands to prepare your backup sources. Refer to the documentation for an upgrade guide.",
)
backupSources = filepath.Join("/tmp", s.c.BackupSources)
// copy before compressing guard against a situation where backup folder's content are still growing.
s.registerHook(hookLevelPlumbing, func(error) error {
if err := remove(backupSources); err != nil {
return fmt.Errorf("createArchive: error removing snapshot: %w", err)
}
s.logger.Info(
fmt.Sprintf("Removed snapshot `%s`.", backupSources),
)
return nil
})
if err := copy.Copy(s.c.BackupSources, backupSources, copy.Options{
PreserveTimes: true,
PreserveOwner: true,
}); err != nil {
return fmt.Errorf("createArchive: error creating snapshot: %w", err)
}
s.logger.Info(
fmt.Sprintf("Created snapshot of `%s` at `%s`.", s.c.BackupSources, backupSources),
)
}
tarFile := s.file
s.registerHook(hookLevelPlumbing, func(error) error {
if err := remove(tarFile); err != nil {
return fmt.Errorf("createArchive: error removing tar file: %w", err)
}
s.logger.Info(
fmt.Sprintf("Removed tar file `%s`.", tarFile),
)
return nil
})
backupPath, err := filepath.Abs(stripTrailingSlashes(backupSources))
if err != nil {
return fmt.Errorf("createArchive: error getting absolute path: %w", err)
}
var filesEligibleForBackup []string
if err := filepath.WalkDir(backupPath, func(path string, di fs.DirEntry, err error) error {
if err != nil {
return err
}
if s.c.BackupExcludeRegexp.Re != nil && s.c.BackupExcludeRegexp.Re.MatchString(path) {
return nil
}
filesEligibleForBackup = append(filesEligibleForBackup, path)
return nil
}); err != nil {
return fmt.Errorf("createArchive: error walking filesystem tree: %w", err)
}
if err := createArchive(filesEligibleForBackup, backupSources, tarFile, s.c.BackupCompression.String(), s.c.GzipParallelism.Int()); err != nil {
return fmt.Errorf("createArchive: error compressing backup folder: %w", err)
}
s.logger.Info(
fmt.Sprintf("Created backup of `%s` at `%s`.", backupSources, tarFile),
)
return nil
}

29
cmd/backup/cron.go
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@ -1,29 +0,0 @@
// Copyright 2024 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import (
"time"
"github.com/robfig/cron/v3"
)
// checkCronSchedule detects whether the given cron expression will actually
// ever be executed or not.
func checkCronSchedule(expression string) (ok bool) {
defer func() {
if err := recover(); err != nil {
ok = false
}
}()
sched, err := cron.ParseStandard(expression)
if err != nil {
ok = false
return
}
now := time.Now()
sched.Next(now) // panics when the cron would never run
ok = true
return
}

63
cmd/backup/encrypt_archive.go Normal file
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@ -0,0 +1,63 @@
// Copyright 2024 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import (
"fmt"
"io"
"os"
"path"
openpgp "github.com/ProtonMail/go-crypto/openpgp/v2"
)
// encryptArchive encrypts the backup file using PGP and the configured passphrase.
// In case no passphrase is given it returns early, leaving the backup file
// untouched.
func (s *script) encryptArchive() error {
if s.c.GpgPassphrase == "" {
return nil
}
gpgFile := fmt.Sprintf("%s.gpg", s.file)
s.registerHook(hookLevelPlumbing, func(error) error {
if err := remove(gpgFile); err != nil {
return fmt.Errorf("encryptArchive: error removing gpg file: %w", err)
}
s.logger.Info(
fmt.Sprintf("Removed GPG file `%s`.", gpgFile),
)
return nil
})
outFile, err := os.Create(gpgFile)
if err != nil {
return fmt.Errorf("encryptArchive: error opening out file: %w", err)
}
defer outFile.Close()
_, name := path.Split(s.file)
dst, err := openpgp.SymmetricallyEncrypt(outFile, []byte(s.c.GpgPassphrase), &openpgp.FileHints{
FileName: name,
}, nil)
if err != nil {
return fmt.Errorf("encryptArchive: error encrypting backup file: %w", err)
}
defer dst.Close()
src, err := os.Open(s.file)
if err != nil {
return fmt.Errorf("encryptArchive: error opening backup file `%s`: %w", s.file, err)
}
if _, err := io.Copy(dst, src); err != nil {
return fmt.Errorf("encryptArchive: error writing ciphertext to file: %w", err)
}
s.file = gpgFile
s.logger.Info(
fmt.Sprintf("Encrypted backup using given passphrase, saving as `%s`.", s.file),
)
return nil
}

8
cmd/backup/exec.go
View File

@ -9,6 +9,7 @@ package main
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"os"
@ -190,13 +191,12 @@ func (s *script) withLabeledCommands(step lifecyclePhase, cb func() error) func(
}
return func() (err error) {
if err = s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-pre", step)); err != nil {
err = fmt.Errorf("withLabeledCommands: %s: error running pre commands: %w", step, err)
err = fmt.Errorf("(*script).withLabeledCommands: %s: error running pre commands: %w", step, err)
return
}
defer func() {
derr := s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-post", step))
if err == nil && derr != nil {
err = derr
if derr := s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-post", step)); derr != nil {
err = errors.Join(err, fmt.Errorf("(*script).withLabeledCommands: error running %s-post commands: %w", step, derr))
}
}()
err = cb()

227
cmd/backup/main.go
View File

@ -5,230 +5,8 @@ package main
import (
"flag"
"fmt"
"log/slog"
"os"
"os/signal"
"runtime"
"syscall"
"github.com/robfig/cron/v3"
)
type command struct {
logger *slog.Logger
}
func newCommand() *command {
return &command{
logger: slog.New(slog.NewTextHandler(os.Stdout, nil)),
}
}
func (c *command) must(err error) {
if err != nil {
c.logger.Error(
fmt.Sprintf("Fatal error running command: %v", err),
"error",
err,
)
os.Exit(1)
}
}
func runScript(c *Config, envVars map[string]string) (err error) {
defer func() {
if derr := recover(); derr != nil {
err = fmt.Errorf("runScript: unexpected panic running script: %v", err)
}
}()
s, unlock, err := newScript(c, envVars)
if err != nil {
err = fmt.Errorf("runScript: error instantiating script: %w", err)
return
}
defer func() {
derr := unlock()
if err != nil {
err = fmt.Errorf("runScript: error releasing file lock: %w", derr)
}
}()
runErr := func() (err error) {
scriptErr := func() error {
if err := s.withLabeledCommands(lifecyclePhaseArchive, func() (err error) {
restartContainersAndServices, err := s.stopContainersAndServices()
// The mechanism for restarting containers is not using hooks as it
// should happen as soon as possible (i.e. before uploading backups or
// similar).
defer func() {
derr := restartContainersAndServices()
if err == nil {
err = derr
}
}()
if err != nil {
return
}
err = s.createArchive()
return
})(); err != nil {
return err
}
if err := s.withLabeledCommands(lifecyclePhaseProcess, s.encryptArchive)(); err != nil {
return err
}
if err := s.withLabeledCommands(lifecyclePhaseCopy, s.copyArchive)(); err != nil {
return err
}
if err := s.withLabeledCommands(lifecyclePhasePrune, s.pruneBackups)(); err != nil {
return err
}
return nil
}()
if hookErr := s.runHooks(scriptErr); hookErr != nil {
if scriptErr != nil {
return fmt.Errorf(
"runScript: error %w executing the script followed by %w calling the registered hooks",
scriptErr,
hookErr,
)
}
return fmt.Errorf(
"runScript: the script ran successfully, but an error occurred calling the registered hooks: %w",
hookErr,
)
}
if scriptErr != nil {
return fmt.Errorf("runScript: error running script: %w", scriptErr)
}
return nil
}()
if runErr != nil {
s.logger.Error(
fmt.Sprintf("Script run failed: %v", runErr), "error", runErr,
)
}
return runErr
}
func (c *command) runInForeground(profileCronExpression string) error {
cr := cron.New(
cron.WithParser(
cron.NewParser(
cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor,
),
),
)
addJob := func(config *Config, name string, envVars map[string]string) error {
if _, err := cr.AddFunc(config.BackupCronExpression, func() {
c.logger.Info(
fmt.Sprintf(
"Now running script on schedule %s",
config.BackupCronExpression,
),
)
if err := runScript(config, envVars); err != nil {
c.logger.Error(
fmt.Sprintf(
"Unexpected error running schedule %s: %v",
config.BackupCronExpression,
err,
),
"error",
err,
)
}
}); err != nil {
return fmt.Errorf("addJob: error adding schedule %s: %w", config.BackupCronExpression, err)
}
c.logger.Info(fmt.Sprintf("Successfully scheduled backup %s with expression %s", name, config.BackupCronExpression))
if ok := checkCronSchedule(config.BackupCronExpression); !ok {
c.logger.Warn(
fmt.Sprintf("Scheduled cron expression %s will never run, is this intentional?", config.BackupCronExpression),
)
}
return nil
}
cs, err := loadEnvFiles("/etc/dockervolumebackup/conf.d")
if err != nil {
if !os.IsNotExist(err) {
return fmt.Errorf("runInForeground: could not load config from environment files: %w", err)
}
c, err := loadEnvVars()
if err != nil {
return fmt.Errorf("runInForeground: could not load config from environment variables: %w", err)
} else {
err = addJob(c, "from environment", nil)
if err != nil {
return fmt.Errorf("runInForeground: error adding job from env: %w", err)
}
}
} else {
c.logger.Info("/etc/dockervolumebackup/conf.d was found, using configuration files from this directory.")
for _, config := range cs {
err = addJob(config.config, config.name, config.additionalEnvVars)
if err != nil {
return fmt.Errorf("runInForeground: error adding jobs from conf files: %w", err)
}
}
}
if profileCronExpression != "" {
if _, err := cr.AddFunc(profileCronExpression, func() {
memStats := runtime.MemStats{}
runtime.ReadMemStats(&memStats)
c.logger.Info(
"Collecting runtime information",
"num_goroutines",
runtime.NumGoroutine(),
"memory_heap_alloc",
formatBytes(memStats.HeapAlloc, false),
"memory_heap_inuse",
formatBytes(memStats.HeapInuse, false),
"memory_heap_sys",
formatBytes(memStats.HeapSys, false),
"memory_heap_objects",
memStats.HeapObjects,
)
}); err != nil {
return fmt.Errorf("runInForeground: error adding profiling job: %w", err)
}
}
var quit = make(chan os.Signal, 1)
signal.Notify(quit, syscall.SIGTERM, syscall.SIGINT)
cr.Start()
<-quit
ctx := cr.Stop()
<-ctx.Done()
return nil
}
func (c *command) runAsCommand() error {
config, err := loadEnvVars()
if err != nil {
return fmt.Errorf("runAsCommand: error loading env vars: %w", err)
}
err = runScript(config, nil)
if err != nil {
return fmt.Errorf("runAsCommand: error running script: %w", err)
}
return nil
}
func main() {
foreground := flag.Bool("foreground", false, "run the tool in the foreground")
profile := flag.String("profile", "", "collect runtime metrics and log them periodically on the given cron expression")
@ -236,7 +14,10 @@ func main() {
c := newCommand()
if *foreground {
c.must(c.runInForeground(*profile))
opts := foregroundOpts{
profileCronExpression: *profile,
}
c.must(c.runInForeground(opts))
} else {
c.must(c.runAsCommand())
}

24
cmd/backup/profile.go Normal file
View File

@ -0,0 +1,24 @@
// Copyright 2024 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import "runtime"
func (c *command) profile() {
memStats := runtime.MemStats{}
runtime.ReadMemStats(&memStats)
c.logger.Info(
"Collecting runtime information",
"num_goroutines",
runtime.NumGoroutine(),
"memory_heap_alloc",
formatBytes(memStats.HeapAlloc, false),
"memory_heap_inuse",
formatBytes(memStats.HeapInuse, false),
"memory_heap_sys",
formatBytes(memStats.HeapSys, false),
"memory_heap_objects",
memStats.HeapObjects,
)
}

65
cmd/backup/prune_backups.go Normal file
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@ -0,0 +1,65 @@
// Copyright 2024 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import (
"fmt"
"slices"
"strings"
"time"
"golang.org/x/sync/errgroup"
)
// pruneBackups rotates away backups from local and remote storages using
// the given configuration. In case the given configuration would delete all
// backups, it does nothing instead and logs a warning.
func (s *script) pruneBackups() error {
if s.c.BackupRetentionDays < 0 {
return nil
}
deadline := time.Now().AddDate(0, 0, -int(s.c.BackupRetentionDays)).Add(s.c.BackupPruningLeeway)
eg := errgroup.Group{}
for _, backend := range s.storages {
b := backend
eg.Go(func() error {
if skipPrune(b.Name(), s.c.BackupSkipBackendsFromPrune) {
s.logger.Info(
fmt.Sprintf("Skipping pruning for backend `%s`.", b.Name()),
)
return nil
}
stats, err := b.Prune(deadline, s.c.BackupPruningPrefix)
if err != nil {
return err
}
s.stats.Lock()
s.stats.Storages[b.Name()] = StorageStats{
Total: stats.Total,
Pruned: stats.Pruned,
}
s.stats.Unlock()
return nil
})
}
if err := eg.Wait(); err != nil {
return fmt.Errorf("pruneBackups: error pruning backups: %w", err)
}
return nil
}
// skipPrune returns true if the given backend name is contained in the
// list of skipped backends.
func skipPrune(name string, skippedBackends []string) bool {
return slices.ContainsFunc(
skippedBackends,
func(b string) bool {
return strings.EqualFold(b, name) // ignore case on both sides
},
)
}

101
cmd/backup/run_script.go Normal file
View File

@ -0,0 +1,101 @@
// Copyright 2024 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import (
"errors"
"fmt"
)
// runScript instantiates a new script object and orchestrates a backup run.
// To ensure it runs mutually exclusive a global file lock is acquired before
// it starts running. Any panic within the script will be recovered and returned
// as an error.
func runScript(c *Config) (err error) {
defer func() {
if derr := recover(); derr != nil {
err = fmt.Errorf("runScript: unexpected panic running script: %v", derr)
}
}()
s := newScript(c)
unlock, lockErr := s.lock("/var/lock/dockervolumebackup.lock")
if lockErr != nil {
err = fmt.Errorf("runScript: error acquiring file lock: %w", lockErr)
return
}
defer func() {
if derr := unlock(); derr != nil {
err = errors.Join(err, fmt.Errorf("runScript: error releasing file lock: %w", derr))
}
}()
unset, err := s.c.applyEnv()
if err != nil {
return fmt.Errorf("runScript: error applying env: %w", err)
}
defer func() {
if derr := unset(); derr != nil {
err = errors.Join(err, fmt.Errorf("runScript: error unsetting environment variables: %w", derr))
}
}()
if initErr := s.init(); initErr != nil {
err = fmt.Errorf("runScript: error instantiating script: %w", initErr)
return
}
return func() (err error) {
scriptErr := func() error {
if err := s.withLabeledCommands(lifecyclePhaseArchive, func() (err error) {
restartContainersAndServices, err := s.stopContainersAndServices()
// The mechanism for restarting containers is not using hooks as it
// should happen as soon as possible (i.e. before uploading backups or
// similar).
defer func() {
if derr := restartContainersAndServices(); derr != nil {
err = errors.Join(err, fmt.Errorf("runScript: error restarting containers and services: %w", derr))
}
}()
if err != nil {
return
}
err = s.createArchive()
return
})(); err != nil {
return err
}
if err := s.withLabeledCommands(lifecyclePhaseProcess, s.encryptArchive)(); err != nil {
return err
}
if err := s.withLabeledCommands(lifecyclePhaseCopy, s.copyArchive)(); err != nil {
return err
}
if err := s.withLabeledCommands(lifecyclePhasePrune, s.pruneBackups)(); err != nil {
return err
}
return nil
}()
if hookErr := s.runHooks(scriptErr); hookErr != nil {
if scriptErr != nil {
return fmt.Errorf(
"runScript: error %w executing the script followed by %w calling the registered hooks",
scriptErr,
hookErr,
)
}
return fmt.Errorf(
"runScript: the script ran successfully, but an error occurred calling the registered hooks: %w",
hookErr,
)
}
if scriptErr != nil {
return fmt.Errorf("runScript: error running script: %w", scriptErr)
}
return nil
}()
}

269
cmd/backup/script.go
View File

@ -6,14 +6,9 @@ package main
import (
"bytes"
"fmt"
"io"
"io/fs"
"log/slog"
"os"
"path"
"path/filepath"
"slices"
"strings"
"text/template"
"time"
@ -25,13 +20,10 @@ import (
"github.com/offen/docker-volume-backup/internal/storage/ssh"
"github.com/offen/docker-volume-backup/internal/storage/webdav"
openpgp "github.com/ProtonMail/go-crypto/openpgp/v2"
"github.com/containrrr/shoutrrr"
"github.com/containrrr/shoutrrr/pkg/router"
"github.com/docker/docker/client"
"github.com/leekchan/timeutil"
"github.com/otiai10/copy"
"golang.org/x/sync/errgroup"
)
// script holds all the stateful information required to orchestrate a
@ -57,9 +49,9 @@ type script struct {
// remote resources like the Docker engine or remote storage locations. All
// reading from env vars or other configuration sources is expected to happen
// in this method.
func newScript(c *Config, envVars map[string]string) (*script, func() error, error) {
func newScript(c *Config) *script {
stdOut, logBuffer := buffer(os.Stdout)
s := &script{
return &script{
c: c,
logger: slog.New(slog.NewTextHandler(stdOut, nil)),
stats: &Stats{
@ -75,30 +67,9 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
},
},
}
}
unlock, err := s.lock("/var/lock/dockervolumebackup.lock")
if err != nil {
return nil, noop, fmt.Errorf("runScript: error acquiring file lock: %w", err)
}
for key, value := range envVars {
currentVal, currentOk := os.LookupEnv(key)
defer func(currentKey, currentVal string, currentOk bool) {
if !currentOk {
_ = os.Unsetenv(currentKey)
} else {
_ = os.Setenv(currentKey, currentVal)
}
}(key, currentVal, currentOk)
if err := os.Setenv(key, value); err != nil {
return nil, unlock, fmt.Errorf(
"Unexpected error overloading environment %s: %w",
s.c.BackupCronExpression,
err,
)
}
}
func (s *script) init() error {
s.registerHook(hookLevelPlumbing, func(error) error {
s.stats.EndTime = time.Now()
s.stats.TookTime = s.stats.EndTime.Sub(s.stats.StartTime)
@ -109,14 +80,14 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
tmplFileName, tErr := template.New("extension").Parse(s.file)
if tErr != nil {
return nil, unlock, fmt.Errorf("newScript: unable to parse backup file extension template: %w", tErr)
return fmt.Errorf("newScript: unable to parse backup file extension template: %w", tErr)
}
var bf bytes.Buffer
if tErr := tmplFileName.Execute(&bf, map[string]string{
"Extension": fmt.Sprintf("tar.%s", s.c.BackupCompression),
}); tErr != nil {
return nil, unlock, fmt.Errorf("newScript: error executing backup file extension template: %w", tErr)
return fmt.Errorf("newScript: error executing backup file extension template: %w", tErr)
}
s.file = bf.String()
@ -127,12 +98,12 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
}
s.file = timeutil.Strftime(&s.stats.StartTime, s.file)
_, err = os.Stat("/var/run/docker.sock")
_, err := os.Stat("/var/run/docker.sock")
_, dockerHostSet := os.LookupEnv("DOCKER_HOST")
if !os.IsNotExist(err) || dockerHostSet {
cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
if err != nil {
return nil, unlock, fmt.Errorf("newScript: failed to create docker client")
return fmt.Errorf("newScript: failed to create docker client")
}
s.cli = cli
s.registerHook(hookLevelPlumbing, func(err error) error {
@ -170,7 +141,7 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
}
s3Backend, err := s3.NewStorageBackend(s3Config, logFunc)
if err != nil {
return nil, unlock, fmt.Errorf("newScript: error creating s3 storage backend: %w", err)
return fmt.Errorf("newScript: error creating s3 storage backend: %w", err)
}
s.storages = append(s.storages, s3Backend)
}
@ -185,7 +156,7 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
}
webdavBackend, err := webdav.NewStorageBackend(webDavConfig, logFunc)
if err != nil {
return nil, unlock, fmt.Errorf("newScript: error creating webdav storage backend: %w", err)
return fmt.Errorf("newScript: error creating webdav storage backend: %w", err)
}
s.storages = append(s.storages, webdavBackend)
}
@ -202,7 +173,7 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
}
sshBackend, err := ssh.NewStorageBackend(sshConfig, logFunc)
if err != nil {
return nil, unlock, fmt.Errorf("newScript: error creating ssh storage backend: %w", err)
return fmt.Errorf("newScript: error creating ssh storage backend: %w", err)
}
s.storages = append(s.storages, sshBackend)
}
@ -226,7 +197,7 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
}
azureBackend, err := azure.NewStorageBackend(azureConfig, logFunc)
if err != nil {
return nil, unlock, fmt.Errorf("newScript: error creating azure storage backend: %w", err)
return fmt.Errorf("newScript: error creating azure storage backend: %w", err)
}
s.storages = append(s.storages, azureBackend)
}
@ -243,7 +214,7 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
}
dropboxBackend, err := dropbox.NewStorageBackend(dropboxConfig, logFunc)
if err != nil {
return nil, unlock, fmt.Errorf("newScript: error creating dropbox storage backend: %w", err)
return fmt.Errorf("newScript: error creating dropbox storage backend: %w", err)
}
s.storages = append(s.storages, dropboxBackend)
}
@ -269,14 +240,14 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
hookLevel, ok := hookLevels[s.c.NotificationLevel]
if !ok {
return nil, unlock, fmt.Errorf("newScript: unknown NOTIFICATION_LEVEL %s", s.c.NotificationLevel)
return fmt.Errorf("newScript: unknown NOTIFICATION_LEVEL %s", s.c.NotificationLevel)
}
s.hookLevel = hookLevel
if len(s.c.NotificationURLs) > 0 {
sender, senderErr := shoutrrr.CreateSender(s.c.NotificationURLs...)
if senderErr != nil {
return nil, unlock, fmt.Errorf("newScript: error creating sender: %w", senderErr)
return fmt.Errorf("newScript: error creating sender: %w", senderErr)
}
s.sender = sender
@ -284,13 +255,13 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
tmpl.Funcs(templateHelpers)
tmpl, err = tmpl.Parse(defaultNotifications)
if err != nil {
return nil, unlock, fmt.Errorf("newScript: unable to parse default notifications templates: %w", err)
return fmt.Errorf("newScript: unable to parse default notifications templates: %w", err)
}
if fi, err := os.Stat("/etc/dockervolumebackup/notifications.d"); err == nil && fi.IsDir() {
tmpl, err = tmpl.ParseGlob("/etc/dockervolumebackup/notifications.d/*.*")
if err != nil {
return nil, unlock, fmt.Errorf("newScript: unable to parse user defined notifications templates: %w", err)
return fmt.Errorf("newScript: unable to parse user defined notifications templates: %w", err)
}
}
s.template = tmpl
@ -311,211 +282,5 @@ func newScript(c *Config, envVars map[string]string) (*script, func() error, err
})
}
return s, unlock, nil
}
// createArchive creates a tar archive of the configured backup location and
// saves it to disk.
func (s *script) createArchive() error {
backupSources := s.c.BackupSources
if s.c.BackupFromSnapshot {
s.logger.Warn(
"Using BACKUP_FROM_SNAPSHOT has been deprecated and will be removed in the next major version.",
)
s.logger.Warn(
"Please use `archive-pre` and `archive-post` commands to prepare your backup sources. Refer to the documentation for an upgrade guide.",
)
backupSources = filepath.Join("/tmp", s.c.BackupSources)
// copy before compressing guard against a situation where backup folder's content are still growing.
s.registerHook(hookLevelPlumbing, func(error) error {
if err := remove(backupSources); err != nil {
return fmt.Errorf("createArchive: error removing snapshot: %w", err)
}
s.logger.Info(
fmt.Sprintf("Removed snapshot `%s`.", backupSources),
)
return nil
})
if err := copy.Copy(s.c.BackupSources, backupSources, copy.Options{
PreserveTimes: true,
PreserveOwner: true,
}); err != nil {
return fmt.Errorf("createArchive: error creating snapshot: %w", err)
}
s.logger.Info(
fmt.Sprintf("Created snapshot of `%s` at `%s`.", s.c.BackupSources, backupSources),
)
}
tarFile := s.file
s.registerHook(hookLevelPlumbing, func(error) error {
if err := remove(tarFile); err != nil {
return fmt.Errorf("createArchive: error removing tar file: %w", err)
}
s.logger.Info(
fmt.Sprintf("Removed tar file `%s`.", tarFile),
)
return nil
})
backupPath, err := filepath.Abs(stripTrailingSlashes(backupSources))
if err != nil {
return fmt.Errorf("createArchive: error getting absolute path: %w", err)
}
var filesEligibleForBackup []string
if err := filepath.WalkDir(backupPath, func(path string, di fs.DirEntry, err error) error {
if err != nil {
return err
}
if s.c.BackupExcludeRegexp.Re != nil && s.c.BackupExcludeRegexp.Re.MatchString(path) {
return nil
}
filesEligibleForBackup = append(filesEligibleForBackup, path)
return nil
}); err != nil {
return fmt.Errorf("createArchive: error walking filesystem tree: %w", err)
}
if err := createArchive(filesEligibleForBackup, backupSources, tarFile, s.c.BackupCompression.String(), s.c.GzipParallelism.Int()); err != nil {
return fmt.Errorf("createArchive: error compressing backup folder: %w", err)
}
s.logger.Info(
fmt.Sprintf("Created backup of `%s` at `%s`.", backupSources, tarFile),
)
return nil
}
// encryptArchive encrypts the backup file using PGP and the configured passphrase.
// In case no passphrase is given it returns early, leaving the backup file
// untouched.
func (s *script) encryptArchive() error {
if s.c.GpgPassphrase == "" {
return nil
}
gpgFile := fmt.Sprintf("%s.gpg", s.file)
s.registerHook(hookLevelPlumbing, func(error) error {
if err := remove(gpgFile); err != nil {
return fmt.Errorf("encryptArchive: error removing gpg file: %w", err)
}
s.logger.Info(
fmt.Sprintf("Removed GPG file `%s`.", gpgFile),
)
return nil
})
outFile, err := os.Create(gpgFile)
if err != nil {
return fmt.Errorf("encryptArchive: error opening out file: %w", err)
}
defer outFile.Close()
_, name := path.Split(s.file)
dst, err := openpgp.SymmetricallyEncrypt(outFile, []byte(s.c.GpgPassphrase), &openpgp.FileHints{
FileName: name,
}, nil)
if err != nil {
return fmt.Errorf("encryptArchive: error encrypting backup file: %w", err)
}
defer dst.Close()
src, err := os.Open(s.file)
if err != nil {
return fmt.Errorf("encryptArchive: error opening backup file `%s`: %w", s.file, err)
}
if _, err := io.Copy(dst, src); err != nil {
return fmt.Errorf("encryptArchive: error writing ciphertext to file: %w", err)
}
s.file = gpgFile
s.logger.Info(
fmt.Sprintf("Encrypted backup using given passphrase, saving as `%s`.", s.file),
)
return nil
}
// copyArchive makes sure the backup file is copied to both local and remote locations
// as per the given configuration.
func (s *script) copyArchive() error {
_, name := path.Split(s.file)
if stat, err := os.Stat(s.file); err != nil {
return fmt.Errorf("copyArchive: unable to stat backup file: %w", err)
} else {
size := stat.Size()
s.stats.BackupFile = BackupFileStats{
Size: uint64(size),
Name: name,
FullPath: s.file,
}
}
eg := errgroup.Group{}
for _, backend := range s.storages {
b := backend
eg.Go(func() error {
return b.Copy(s.file)
})
}
if err := eg.Wait(); err != nil {
return fmt.Errorf("copyArchive: error copying archive: %w", err)
}
return nil
}
// pruneBackups rotates away backups from local and remote storages using
// the given configuration. In case the given configuration would delete all
// backups, it does nothing instead and logs a warning.
func (s *script) pruneBackups() error {
if s.c.BackupRetentionDays < 0 {
return nil
}
deadline := time.Now().AddDate(0, 0, -int(s.c.BackupRetentionDays)).Add(s.c.BackupPruningLeeway)
eg := errgroup.Group{}
for _, backend := range s.storages {
b := backend
eg.Go(func() error {
if skipPrune(b.Name(), s.c.BackupSkipBackendsFromPrune) {
s.logger.Info(
fmt.Sprintf("Skipping pruning for backend `%s`.", b.Name()),
)
return nil
}
stats, err := b.Prune(deadline, s.c.BackupPruningPrefix)
if err != nil {
return err
}
s.stats.Lock()
s.stats.Storages[b.Name()] = StorageStats{
Total: stats.Total,
Pruned: stats.Pruned,
}
s.stats.Unlock()
return nil
})
}
if err := eg.Wait(); err != nil {
return fmt.Errorf("pruneBackups: error pruning backups: %w", err)
}
return nil
}
// skipPrune returns true if the given backend name is contained in the
// list of skipped backends.
func skipPrune(name string, skippedBackends []string) bool {
return slices.ContainsFunc(
skippedBackends,
func(b string) bool {
return strings.EqualFold(b, name) // ignore case on both sides
},
)
}

22
cmd/backup/util.go
View File

@ -9,6 +9,9 @@ import (
"io"
"os"
"sync"
"time"
"github.com/robfig/cron/v3"
)
var noop = func() error { return nil }
@ -79,3 +82,22 @@ func (c *concurrentSlice[T]) append(v T) {
func (c *concurrentSlice[T]) value() []T {
return c.val
}
// checkCronSchedule detects whether the given cron expression will actually
// ever be executed or not.
func checkCronSchedule(expression string) (ok bool) {
defer func() {
if err := recover(); err != nil {
ok = false
}
}()
sched, err := cron.ParseStandard(expression)
if err != nil {
ok = false
return
}
now := time.Now()
sched.Next(now) // panics when the cron would never run
ok = true
return
}