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Lock needs to be acquired when instantiating script
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@m90
m90 committed Feb 13, 2024
1 parent 36f4b98 commit 44f7ab9
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Showing 2 changed files with 51 additions and 55 deletions.
46 changes: 6 additions & 40 deletions cmd/backup/main.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,53 +43,19 @@ func runScript(c *Config, envVars map[string]string) (err error) {
}
}()

s, err := newScript(c)
s, unlock, err := newScript(c, envVars)
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")
defer func() {
derr := unlock()
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)
}
}()

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)
}
s.logger.Info(fmt.Sprintf("unset %v: %v", currentKey, currentVal))
}(key, currentVal, currentOk)

if err := os.Setenv(key, value); err != nil {
return fmt.Errorf(
"Unexpected error overloading environment %s: %w",
s.c.BackupCronExpression,
err,
)
}
s.logger.Info(fmt.Sprintf("set %v: %v", key, value))
}

if s.c.BackupFilenameExpand {
s.file = os.ExpandEnv(s.file)
s.c.BackupLatestSymlink = os.ExpandEnv(s.c.BackupLatestSymlink)
s.c.BackupPruningPrefix = os.ExpandEnv(s.c.BackupPruningPrefix)
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()
Expand Down
60 changes: 45 additions & 15 deletions cmd/backup/script.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ 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) (*script, error) {
func newScript(c *Config, envVars map[string]string) (*script, func() error, error) {
stdOut, logBuffer := buffer(os.Stdout)
s := &script{
c: c,
Expand All @@ -76,6 +76,31 @@ func newScript(c *Config) (*script, error) {
},
}

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)
}
s.logger.Info(fmt.Sprintf("unset %v: %v", 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,
)
}
s.logger.Info(fmt.Sprintf("set %v: %v", key, value))
}
s.registerHook(hookLevelPlumbing, func(error) error {
s.stats.EndTime = time.Now()
s.stats.TookTime = s.stats.EndTime.Sub(s.stats.StartTime)
Expand All @@ -86,25 +111,30 @@ func newScript(c *Config) (*script, error) {

tmplFileName, tErr := template.New("extension").Parse(s.file)
if tErr != nil {
return nil, fmt.Errorf("newScript: unable to parse backup file extension template: %w", tErr)
return nil, unlock, 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, fmt.Errorf("newScript: error executing backup file extension template: %w", tErr)
return nil, unlock, fmt.Errorf("newScript: error executing backup file extension template: %w", tErr)
}
s.file = bf.String()

if s.c.BackupFilenameExpand {
s.file = os.ExpandEnv(s.file)
s.c.BackupLatestSymlink = os.ExpandEnv(s.c.BackupLatestSymlink)
s.c.BackupPruningPrefix = os.ExpandEnv(s.c.BackupPruningPrefix)
}
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, fmt.Errorf("newScript: failed to create docker client")
return nil, unlock, fmt.Errorf("newScript: failed to create docker client")
}
s.cli = cli
s.registerHook(hookLevelPlumbing, func(err error) error {
Expand Down Expand Up @@ -142,7 +172,7 @@ func newScript(c *Config) (*script, error) {
}
s3Backend, err := s3.NewStorageBackend(s3Config, logFunc)
if err != nil {
return nil, fmt.Errorf("newScript: error creating s3 storage backend: %w", err)
return nil, unlock, fmt.Errorf("newScript: error creating s3 storage backend: %w", err)
}
s.storages = append(s.storages, s3Backend)
}
Expand All @@ -157,7 +187,7 @@ func newScript(c *Config) (*script, error) {
}
webdavBackend, err := webdav.NewStorageBackend(webDavConfig, logFunc)
if err != nil {
return nil, fmt.Errorf("newScript: error creating webdav storage backend: %w", err)
return nil, unlock, fmt.Errorf("newScript: error creating webdav storage backend: %w", err)
}
s.storages = append(s.storages, webdavBackend)
}
Expand All @@ -174,7 +204,7 @@ func newScript(c *Config) (*script, error) {
}
sshBackend, err := ssh.NewStorageBackend(sshConfig, logFunc)
if err != nil {
return nil, fmt.Errorf("newScript: error creating ssh storage backend: %w", err)
return nil, unlock, fmt.Errorf("newScript: error creating ssh storage backend: %w", err)
}
s.storages = append(s.storages, sshBackend)
}
Expand All @@ -198,7 +228,7 @@ func newScript(c *Config) (*script, error) {
}
azureBackend, err := azure.NewStorageBackend(azureConfig, logFunc)
if err != nil {
return nil, fmt.Errorf("newScript: error creating azure storage backend: %w", err)
return nil, unlock, fmt.Errorf("newScript: error creating azure storage backend: %w", err)
}
s.storages = append(s.storages, azureBackend)
}
Expand All @@ -215,7 +245,7 @@ func newScript(c *Config) (*script, error) {
}
dropboxBackend, err := dropbox.NewStorageBackend(dropboxConfig, logFunc)
if err != nil {
return nil, fmt.Errorf("newScript: error creating dropbox storage backend: %w", err)
return nil, unlock, fmt.Errorf("newScript: error creating dropbox storage backend: %w", err)
}
s.storages = append(s.storages, dropboxBackend)
}
Expand All @@ -241,28 +271,28 @@ func newScript(c *Config) (*script, error) {

hookLevel, ok := hookLevels[s.c.NotificationLevel]
if !ok {
return nil, fmt.Errorf("newScript: unknown NOTIFICATION_LEVEL %s", s.c.NotificationLevel)
return nil, unlock, 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, fmt.Errorf("newScript: error creating sender: %w", senderErr)
return nil, unlock, fmt.Errorf("newScript: error creating sender: %w", senderErr)
}
s.sender = sender

tmpl := template.New("")
tmpl.Funcs(templateHelpers)
tmpl, err = tmpl.Parse(defaultNotifications)
if err != nil {
return nil, fmt.Errorf("newScript: unable to parse default notifications templates: %w", err)
return nil, unlock, 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, fmt.Errorf("newScript: unable to parse user defined notifications templates: %w", err)
return nil, unlock, fmt.Errorf("newScript: unable to parse user defined notifications templates: %w", err)
}
}
s.template = tmpl
Expand All @@ -283,7 +313,7 @@ func newScript(c *Config) (*script, error) {
})
}

return s, nil
return s, unlock, nil
}

// createArchive creates a tar archive of the configured backup location and
Expand Down

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