Rename backups => snapshot

cmd/backup.go

@@ -1,106 +0,0 @@
-package cmd
-
-import (
-	"fmt"
-	"os"
-	"path/filepath"
-
-	wisski_distillery "github.com/FAU-CDI/wisski-distillery"
-	"github.com/FAU-CDI/wisski-distillery/env"
-	"github.com/FAU-CDI/wisski-distillery/internal/logging"
-	"github.com/FAU-CDI/wisski-distillery/internal/targz"
-	"github.com/tkw1536/goprogram/exit"
-)
-
-// BackupInstance is the 'backup_instance' command
-var BackupInstance wisski_distillery.Command = backupInstance{}
-
-type backupInstance struct {
-	Keepalive   bool `short:"k" long:"keepalive" description:"Keep instance running while taking a backup. Might lead to inconsistent state"`
-	Positionals struct {
-		Slug    string `positional-arg-name:"SLUG" required:"1-1" description:"slug of instance to show info about"`
-		Outfile string `positional-arg-name:"OUTFILE" description:"Destination file to write backup to"`
-	} `positional-args:"true"`
-}
-
-func (backupInstance) Description() wisski_distillery.Description {
-	return wisski_distillery.Description{
-		Requirements: env.Requirements{
-			NeedsConfig: true,
-		},
-		Command:     "backup_instance",
-		Description: "Makes a backup of a specific instance",
-	}
-}
-
-var errBackupFailed = exit.Error{
-	Message:  "Failed to make a backup",
-	ExitCode: exit.ExitGeneric,
-}
-
-func (bi backupInstance) Run(context wisski_distillery.Context) error {
-	dis := context.Environment
-	instance, err := dis.Instance(bi.Positionals.Slug)
-	if err != nil {
-		return err
-	}
-
-	// TODO: Allow skipping backups of individual parts and make them concurrent!
-
-	// start the backup and shutdown the instance (if requested)
-	logging.LogMessage(context.IOStream, "Creating backup of instance %s", bi.Positionals.Slug)
-
-	// create a new temporary directory
-	logging.LogMessage(context.IOStream, "Creating temporary backup directory")
-	path, err := dis.NewInprogressBackupPath(instance.Slug)
-	if err != nil {
-		return errBackupFailed.Wrap(err)
-	}
-	defer func() {
-		logging.LogMessage(context.IOStream, "Removing temporary backup directory")
-		os.RemoveAll(path) // TODO: Turn this on again
-	}()
-
-	// make a snapshot and write out the report also!
-	logging.LogOperation(func() error {
-		sreport := instance.Snapshot(context.IOStream, bi.Keepalive, path)
-
-		logging.LogOperation(func() error {
-			reportPath := filepath.Join(path, "report.txt")
-			context.Println(reportPath)
-
-			// create the report file!
-			report, err := os.Create(reportPath)
-			if err != nil {
-				return err
-			}
-			defer report.Close()
-
-			// print the report into it!
-			_, err = fmt.Fprintf(report, "%#v\n", sreport)
-			return err
-		}, context.IOStream, "Writing snapshot report")
-
-		return nil
-	}, context.IOStream, "Creating snapshot")
-
-	// copy everything into the final file!
-	finalPath := bi.Positionals.Outfile
-	if finalPath == "" {
-		finalPath = dis.FinalBackupArchive(instance.Slug)
-	}
-
-	if err := logging.LogOperation(func() error {
-		context.IOStream.Println(finalPath)
-
-		targz.Package(finalPath, path, func(src string) {
-			context.Println(src)
-		})
-		return err
-	}, context.IOStream, "Writing final backup"); err != nil {
-		return errBackupFailed.Wrap(err)
-	}
-	context.Printf("Wrote %s\n", finalPath)
-
-	return nil
-}

cmd/snapshot.go

@@ -0,0 +1,110 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	wisski_distillery "github.com/FAU-CDI/wisski-distillery"
+	"github.com/FAU-CDI/wisski-distillery/env"
+	"github.com/FAU-CDI/wisski-distillery/internal/logging"
+	"github.com/FAU-CDI/wisski-distillery/internal/targz"
+	"github.com/tkw1536/goprogram/exit"
+)
+
+// Snapshot creates a snapshot of an instance
+var Snapshot wisski_distillery.Command = snapshot{}
+
+type snapshot struct {
+	Keepalive bool `short:"k" long:"keepalive" description:"Keep instance running while taking a backup. Might lead to inconsistent state"`
+
+	Positionals struct {
+		Slug string `positional-arg-name:"SLUG" required:"1-1" description:"slug of instance to take a snapshot of"`
+		Dest string `positional-arg-name:"DEST" description:"Destination path to write snapshot archive to. Defaults to the snapshots/archives/ directory"`
+	} `positional-args:"true"`
+}
+
+func (snapshot) Description() wisski_distillery.Description {
+	return wisski_distillery.Description{
+		Requirements: env.Requirements{
+			NeedsConfig: true,
+		},
+		Command:     "snapshot",
+		Description: "Generates a snapshot archive for the provided archive",
+	}
+}
+
+var errSnapshotFailed = exit.Error{
+	Message:  "Failed to make a snapshot",
+	ExitCode: exit.ExitGeneric,
+}
+
+func (bi snapshot) Run(context wisski_distillery.Context) error {
+	dis := context.Environment
+	instance, err := dis.Instance(bi.Positionals.Slug)
+	if err != nil {
+		return err
+	}
+
+	// TODO: Allow skipping backups of individual parts and make them concurrent!
+
+	// start the snapshot and shutdown the instance (if requested)
+	logging.LogMessage(context.IOStream, "Creating snapshot of instance %s", bi.Positionals.Slug)
+
+	// create a new temporary directory
+	logging.LogMessage(context.IOStream, "Creating new snapshot staging directory")
+	sPath, err := dis.NewSnapshotStagingDir(instance.Slug)
+	if err != nil {
+		return errSnapshotFailed.Wrap(err)
+	}
+	defer func() {
+		logging.LogMessage(context.IOStream, "Removing snapshot staging directory")
+		os.RemoveAll(sPath)
+	}()
+
+	// take a snapshot into the staging area!
+	sreport := instance.Snapshot(context.IOStream, bi.Keepalive, sPath)
+
+	// write out the report!
+	logging.LogOperation(func() error {
+
+		logging.LogOperation(func() error {
+			reportPath := filepath.Join(sPath, "report.txt")
+			context.Println(reportPath)
+
+			// create the report file!
+			report, err := os.Create(reportPath)
+			if err != nil {
+				return err
+			}
+			defer report.Close()
+
+			// print the report into it!
+			_, err = fmt.Fprintf(report, "%#v\n", sreport)
+			return err
+		}, context.IOStream, "Writing snapshot report")
+
+		return nil
+	}, context.IOStream, "Creating snapshot")
+
+	// copy everything into the final archive
+
+	finalPath := bi.Positionals.Dest
+	if finalPath == "" {
+		finalPath = dis.NewSnapshotArchivePath(instance.Slug)
+	}
+
+	if err := logging.LogOperation(func() error {
+		context.IOStream.Println(finalPath)
+
+		targz.Package(finalPath, sPath, func(src string) {
+			context.Println(src)
+		})
+		return err
+	}, context.IOStream, "Writing final backup"); err != nil {
+		return errSnapshotFailed.Wrap(err)
+	}
+	context.Printf("Wrote %s\n", finalPath)
+
+	return nil
+}

cmd/system_update.go

@@ -81,8 +81,8 @@ func (si systemupdate) Run(context wisski_distillery.Context) error {
 	for _, d := range []string{
 		dis.Config.DeployRoot,
 		dis.InstancesDir(),
-		dis.InprogressBackupPath(),
+		dis.SnapshotsStagingPath(),
-		dis.FinalBackupPath(),
+		dis.SnapshotsArchivePath(),
 	} {
 		context.Println(d)
 		if err := os.MkdirAll(d, os.ModeDir); err != nil {

cmd/wdcli/main.go

@@ -44,7 +44,7 @@ func init() {
 	wdcli.Register(cmd.UpdatePrefixConfig) // TODO: Move into post-instance configuration
 
 	// backup & cron
-	wdcli.Register(cmd.BackupInstance)
+	wdcli.Register(cmd.Snapshot)
 	// wdcli.Register(cmd.BackupAll)
 	wdcli.Register(cmd.Cron)
 }

env/backup.go

@@ -1,52 +0,0 @@
-package env
-
-import (
-	"fmt"
-	"os"
-	"path/filepath"
-	"sync/atomic"
-	"time"
-)
-
-func (dis Distillery) BackupDir() string {
-	return filepath.Join(dis.Config.DeployRoot, "backups")
-}
-
-func (dis Distillery) InprogressBackupPath() string {
-	return filepath.Join(dis.BackupDir(), "inprogress")
-}
-
-func (dis Distillery) FinalBackupPath() string {
-	return filepath.Join(dis.BackupDir(), "final")
-}
-
-// NewFinalBackupFile returns the path to a new final backup file.
-func (dis Distillery) FinalBackupArchive(prefix string) string {
-	counter := atomic.AddUint64(&globalBackupCounter, 1)
-
-	// generate a new name with the current time, a global counter, and the prefix
-	name := fmt.Sprintf("%s-%d-%d.tar.gz", prefix, time.Now().Unix(), counter)
-	path := filepath.Join(dis.FinalBackupPath(), name)
-
-	return path
-}
-
-var globalBackupCounter uint64
-
-// NewInprogressBackupPath returns the path to a new inprogress backup directory.
-// The directory is guaranteed to have been freshly created.
-func (dis Distillery) NewInprogressBackupPath(prefix string) (string, error) {
-	counter := atomic.AddUint64(&globalBackupCounter, 1)
-
-	// generate a new name with the current time, a global counter, and the prefix
-	name := fmt.Sprintf("%s-%d-%d", prefix, time.Now().Unix(), counter)
-	path := filepath.Join(dis.InprogressBackupPath(), name)
-
-	// create the directory
-	if err := os.Mkdir(path, os.ModeDir); err != nil {
-		return "", err
-	}
-
-	// and it is here!
-	return path, nil
-}

env/snapshot.go

@@ -6,12 +6,62 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"time"
 
 	"github.com/FAU-CDI/wisski-distillery/internal/fsx"
 	"github.com/FAU-CDI/wisski-distillery/internal/logging"
+	"github.com/FAU-CDI/wisski-distillery/internal/password"
 	"github.com/tkw1536/goprogram/stream"
 )
 
+// SnapshotsDir returns the path that contains all snapshot related data.
+func (dis Distillery) SnapshotsDir() string {
+	return filepath.Join(dis.Config.DeployRoot, "snapshots")
+}
+
+// SnapshotsStagingPath returns the path to the directory containing a temporary staging area for snapshots.
+// Use NewSnapshotStagingDir to generate a new staging area.
+func (dis Distillery) SnapshotsStagingPath() string {
+	return filepath.Join(dis.SnapshotsDir(), "staging")
+}
+
+// SnapshotsArchivePath returns the path to the directory containing all exported archives.
+// Use NewSnapshotArchivePath to generate a path to a new archive in this directory.
+func (dis Distillery) SnapshotsArchivePath() string {
+	return filepath.Join(dis.SnapshotsDir(), "archives")
+}
+
+// NewSnapshotArchivePath returns the path to a new archive with the provided prefix.
+// The path is guaranteed to not exist.
+func (dis Distillery) NewSnapshotArchivePath(prefix string) (path string) {
+	// TODO: Consider moving these into a subdirectory with the provided prefix.
+	for path == "" || fsx.Exists(path) {
+		name := dis.newSnapshotName(prefix) + ".tar.gz"
+		path = filepath.Join(dis.SnapshotsArchivePath(), name)
+	}
+	return
+}
+
+// newSnapshot name returns a new basename for a snapshot with the provided prefix.
+// The name is guaranteed to be unique within this process.
+func (Distillery) newSnapshotName(prefix string) string {
+	suffix, _ := password.Password(64) // silently ignore any errors!
+	return fmt.Sprintf("%s-%d-%s", prefix, time.Now().Unix(), suffix)
+}
+
+// NewSnapshotStagingDir returns the path to a new snapshot directory.
+// The directory is guaranteed to have been freshly created.
+func (dis Distillery) NewSnapshotStagingDir(prefix string) (path string, err error) {
+	for path == "" || os.IsExist(err) {
+		path = filepath.Join(dis.SnapshotsStagingPath(), dis.newSnapshotName(prefix))
+		err = os.Mkdir(path, os.ModeDir)
+	}
+	if err != nil {
+		path = ""
+	}
+	return
+}
+
 type SnapshotReport struct {
 	Keepalive bool        // was the instance alive while running the snapshot?
 	Panic     interface{} // was there a panic?

internal/fsx/type.go

@@ -2,6 +2,11 @@ package fsx
 
 import "os"
 
+func Exists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
 func IsDirectory(path string) bool {
 	info, err := os.Stat(path)
 	return err == nil && info.Mode().IsDir()

internal/password/password.go

@@ -10,28 +10,33 @@ import (
 // NOTE(twiesing): A bunch of scripts cannot properly handle the extra characters in the password.
 // For now it is disabled, but it should be re-enabled later.
 const PasswordCharSet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" // + "!@#$%&*"
-const PasswordCharCount = len(PasswordCharSet)
+var passwordCharCount = big.NewInt(int64(len(PasswordCharSet)))
 
-// Password returns a randomly generated password with the provided length.
+// Password returns a randomly generated string with the provided length.
+// It consists of alphanumeric characters only.
+//
+// When an error occurs, it is guaranteed to return "", err.
 // [rand.Reader] is used as the source of randomness.
 func Password(length int) (string, error) {
 	if length < 0 {
 		panic("length < 0")
 	}
 
+	// create a buffer to write the string to!
 	var password strings.Builder
 	password.Grow(length)
 
 	for i := 0; i < length; i++ {
 
-		// grab a random index!
+		// grab a random bIndex!
-		index, err := rand.Int(rand.Reader, big.NewInt(int64(PasswordCharCount)))
+		bIndex, err := rand.Int(rand.Reader, passwordCharCount)
 		if err != nil {
 			return "", err
 		}
 
 		// and use that index!
-		if err := password.WriteByte(PasswordCharSet[int(index.Int64())]); err != nil {
+		index := int(bIndex.Int64())
+		if err := password.WriteByte(PasswordCharSet[index]); err != nil {
 			return "", err
 		}
 	}