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Hoist control for exiting script a level up (#348)

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* Hoist control for exiting script a level up

* Do not accidentally nil out errors

* Log when running schedule

* Remove duplicate log line

* Warn on cron schedule that will never run
This commit is contained in:
Frederik Ring 2024-02-09 10:24:28 +01:00
parent 69eceb3982
commit 65626dd3d4
6 changed files with 221 additions and 136 deletions
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44
cmd/backup/config_provider.go
View File

@ -38,7 +38,7 @@ func loadConfig(lookup envProxy) (*Config, error) {
var c = &Config{}
if err := envconfig.Process("", c); err != nil {
return nil, fmt.Errorf("failed to process configuration values, error: %w", err)
return nil, fmt.Errorf("loadConfig: failed to process configuration values: %w", err)
}
return c, nil
@ -48,33 +48,39 @@ func loadEnvVars() (*Config, error) {
return loadConfig(os.LookupEnv)
}
func loadEnvFiles(directory string) ([]*Config, error) {
type configFile struct {
name string
config *Config
}
func loadEnvFiles(directory string) ([]configFile, error) {
items, err := os.ReadDir(directory)
if err != nil {
if os.IsNotExist(err) {
return nil, err
}
return nil, fmt.Errorf("failed to read files from env directory, error: %w", err)
return nil, fmt.Errorf("loadEnvFiles: failed to read files from env directory: %w", err)
}
var cs = make([]*Config, 0)
cs := []configFile{}
for _, item := range items {
if !item.IsDir() {
p := filepath.Join(directory, item.Name())
envFile, err := godotenv.Read(p)
if err != nil {
return nil, fmt.Errorf("error reading config file %s, error: %w", p, err)
}
lookup := func(key string) (string, bool) {
val, ok := envFile[key]
return val, ok
}
c, err := loadConfig(lookup)
if err != nil {
return nil, fmt.Errorf("error loading config from file %s, error: %w", p, err)
}
cs = append(cs, c)
if item.IsDir() {
continue
}
p := filepath.Join(directory, item.Name())
envFile, err := godotenv.Read(p)
if err != nil {
return nil, fmt.Errorf("loadEnvFiles: error reading config file %s: %w", p, err)
}
lookup := func(key string) (string, bool) {
val, ok := envFile[key]
return val, ok
}
c, err := loadConfig(lookup)
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()})
}
return cs, nil

29
cmd/backup/cron.go Normal file
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@ -0,0 +1,29 @@
// 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
}

15
cmd/backup/exec.go
View File

@ -188,13 +188,18 @@ func (s *script) withLabeledCommands(step lifecyclePhase, cb func() error) func(
if s.cli == nil {
return cb
}
return func() error {
if err := s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-pre", step)); err != nil {
return fmt.Errorf("withLabeledCommands: %s: error running pre commands: %w", step, err)
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)
return
}
defer func() {
s.must(s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-post", step)))
derr := s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-post", step))
if err == nil && derr != nil {
err = derr
}
}()
return cb()
err = cb()
return
}
}

256
cmd/backup/main.go
View File

@ -14,79 +14,115 @@ import (
"github.com/robfig/cron/v3"
)
func runScript(c *Config) (ret error) {
s, err := newScript(c)
if err != nil {
return err
}
unlock, err := s.lock("/var/lock/dockervolumebackup.lock")
if err != nil {
return err
}
defer func() {
err = unlock()
if err != nil {
ret = err
}
}()
defer func() {
if pArg := recover(); pArg != nil {
if err, ok := pArg.(error); ok {
s.logger.Error(
fmt.Sprintf("Executing the script encountered a panic: %v", err),
)
if hookErr := s.runHooks(err); hookErr != nil {
s.logger.Error(
fmt.Sprintf("An error occurred calling the registered hooks: %s", hookErr),
)
}
ret = err
} else {
s.logger.Error(
fmt.Sprintf("Executing the script encountered an unrecoverable panic: %v", err),
)
panic(pArg)
}
}
if err := s.runHooks(nil); err != nil {
s.logger.Error(
fmt.Sprintf(
"Backup procedure ran successfully, but an error ocurred calling the registered hooks: %v",
err,
),
)
ret = err
}
s.logger.Info("Finished running backup tasks.")
}()
s.must(s.withLabeledCommands(lifecyclePhaseArchive, func() 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() {
s.must(restartContainersAndServices())
}()
if err != nil {
return err
}
return s.createArchive()
})())
s.must(s.withLabeledCommands(lifecyclePhaseProcess, s.encryptArchive)())
s.must(s.withLabeledCommands(lifecyclePhaseCopy, s.copyArchive)())
s.must(s.withLabeledCommands(lifecyclePhasePrune, s.pruneBackups)())
return nil
type command struct {
logger *slog.Logger
}
func runInForeground() error {
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) (err error) {
defer func() {
if derr := recover(); derr != nil {
err = fmt.Errorf("runScript: unexpected panic running script: %v", err)
}
}()
s, err := newScript(c)
if err != nil {
err = fmt.Errorf("runScript: error instantiating script: %w", err)
return
}
runErr := func() (err error) {
unlock, err := s.lock("/var/lock/dockervolumebackup.lock")
if err != nil {
err = fmt.Errorf("runScript: error acquiring file lock: %w", err)
return
}
defer func() {
derr := unlock()
if err == nil && derr != nil {
err = fmt.Errorf("runScript: error releasing file lock: %w", derr)
}
}()
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() error {
cr := cron.New(
cron.WithParser(
cron.NewParser(
@ -95,36 +131,60 @@ func runInForeground() error {
),
)
addJob := func(c *Config) error {
_, err := cr.AddFunc(c.BackupCronExpression, func() {
err := runScript(c)
if err != nil {
slog.Error("unexpected error during backup", "error", err)
addJob := func(config *Config, name 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); err != nil {
c.logger.Error(
fmt.Sprintf(
"Unexpected error running schedule %s: %v",
config.BackupCronExpression,
err,
),
"error",
err,
)
}
})
return 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("could not load config from environment files, error: %w", err)
return fmt.Errorf("runInForeground: could not load config from environment files: %w", err)
}
c, err := loadEnvVars()
if err != nil {
return fmt.Errorf("could not load config from environment variables")
return fmt.Errorf("runInForeground: could not load config from environment variables: %w", err)
} else {
err = addJob(c)
err = addJob(c, "from environment")
if err != nil {
return fmt.Errorf("could not add cron job, error: %w", err)
return fmt.Errorf("runInForeground: error adding job from env: %w", err)
}
}
} else {
for _, c := range cs {
err = addJob(c)
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)
if err != nil {
return fmt.Errorf("could not add cron job, error: %w", err)
return fmt.Errorf("runInForeground: error adding jobs from conf files: %w", err)
}
}
}
@ -139,33 +199,27 @@ func runInForeground() error {
return nil
}
func runAsCommand() error {
c, err := loadEnvVars()
func (c *command) runAsCommand() error {
config, err := loadEnvVars()
if err != nil {
return fmt.Errorf("could not load config from environment variables, error: %w", err)
return fmt.Errorf("runAsCommand: error loading env vars: %w", err)
}
err = runScript(c)
err = runScript(config)
if err != nil {
return fmt.Errorf("unexpected error during backup, error: %w", err)
return fmt.Errorf("runAsCommand: error running script: %w", err)
}
return nil
}
func main() {
serve := flag.Bool("foreground", false, "run the tool in the foreground")
foreground := flag.Bool("foreground", false, "run the tool in the foreground")
flag.Parse()
var err error
if *serve {
err = runInForeground()
c := newCommand()
if *foreground {
c.must(c.runInForeground())
} else {
err = runAsCommand()
}
if err != nil {
slog.Error("ran into an issue during execution", "error", err)
os.Exit(1)
c.must(c.runAsCommand())
}
}

11
cmd/backup/script.go
View File

@ -480,17 +480,6 @@ func (s *script) pruneBackups() error {
return nil
}
// must exits the script run prematurely in case the given error
// is non-nil.
func (s *script) must(err error) {
if err != nil {
s.logger.Error(
fmt.Sprintf("Fatal error running backup: %s", err),
)
panic(err)
}
}
// skipPrune returns true if the given backend name is contained in the
// list of skipped backends.
func skipPrune(name string, skippedBackends []string) bool {

2
test/confd/run.sh
View File

@ -13,6 +13,8 @@ docker compose up -d --quiet-pull
# sleep until a backup is guaranteed to have happened on the 1 minute schedule
sleep 100
docker compose logs backup
if [ ! -f "$LOCAL_DIR/conf.tar.gz" ]; then
fail "Config from file was not used."
fi