wisski-cloud-distillery/internal/backup/backup.go
2022-09-26 16:10:25 +02:00

141 lines
3.7 KiB
Go

// Package backup implements Distillery backups.
package backup
import (
"path/filepath"
"sync"
"time"
"github.com/FAU-CDI/wisski-distillery/internal/component"
"github.com/FAU-CDI/wisski-distillery/internal/wisski"
"github.com/FAU-CDI/wisski-distillery/pkg/environment"
"github.com/FAU-CDI/wisski-distillery/pkg/logging"
"github.com/tkw1536/goprogram/stream"
"golang.org/x/exp/slices"
)
// New create a new Backup
func New(io stream.IOStream, dis *wisski.Distillery, description Description) (backup Backup) {
backup.Description = description
// catch anything critical that happened during the snapshot
defer func() {
backup.ErrPanic = recover()
}()
// do the create keeping track of time!
logging.LogOperation(func() error {
backup.StartTime = time.Now().UTC()
backup.run(io, dis)
backup.EndTime = time.Now().UTC()
return nil
}, io, "Writing backup files")
return
}
type backupResult struct {
name string
err error
}
func (backup *Backup) run(io stream.IOStream, dis *wisski.Distillery) {
backups := dis.Backupable()
files := make(chan string, len(backups)) // channel for files being added into the backups
results := make(chan backupResult, len(backups)) // channel for results to be stored into
backup.ComponentErrors = make(map[string]error, len(backups))
wg := &sync.WaitGroup{} // to wait for the results
wg.Add(len(backups)) // tell the group about all the operations
for _, bc := range backups {
go func(bc component.Backupable, context component.BackupContext) {
defer wg.Done()
// make the backup and store the result
results <- backupResult{
name: bc.Name(),
err: bc.Backup(context),
}
}(bc, &context{
env: dis.Core.Environment,
io: io,
dst: filepath.Join(backup.Description.Dest, bc.BackupName()),
files: files,
})
}
// backup instances
wg.Add(1)
go func() {
defer wg.Done()
instancesBackupDir := filepath.Join(backup.Description.Dest, "instances")
if err := dis.Core.Environment.Mkdir(instancesBackupDir, environment.DefaultDirPerm); err != nil {
backup.InstanceListErr = err
return
}
// list all instances
instances, err := dis.Instances().All()
if err != nil {
backup.InstanceListErr = err
return
}
backup.InstanceSnapshots = make([]wisski.Snapshot, len(instances))
for i, instance := range instances {
backup.InstanceSnapshots[i] = func() wisski.Snapshot {
dir := filepath.Join(instancesBackupDir, instance.Slug)
if err := dis.Core.Environment.Mkdir(dir, environment.DefaultDirPerm); err != nil {
return wisski.Snapshot{
ErrPanic: err,
}
}
files <- dir
return dis.Snapshot(instance, io.NonInteractive(), wisski.SnapshotDescription{
Dest: dir,
})
}()
}
}()
// finish processing all the results as soon as the group is done.
go func() {
defer close(results)
wg.Wait()
}()
// finish the message processing once results are finished.
go func() {
defer close(files) // no more file processing!
for result := range results {
backup.ComponentErrors[result.name] = result.err
}
}()
for file := range files {
// get the relative path to the root of the manifest.
// nothing *should* go wrong, but in case it does, use the original path.
path, err := filepath.Rel(backup.Description.Dest, file)
if err != nil {
path = file
}
// write it to the command line
// and also add it to the manifest
io.Printf("\033[2K\r%s", path)
backup.Manifest = append(backup.Manifest, path)
}
slices.Sort(backup.Manifest) // backup the manifest
io.Println("")
// sort the instances manifest
slices.SortFunc(backup.InstanceSnapshots, func(a, b wisski.Snapshot) bool {
return a.Instance.Slug < b.Instance.Slug
})
}