component: Add 'Snapshottable' component

internal/component/backup.go

@@ -3,6 +3,7 @@ package component
 import (
 	"io"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/models"
 	"github.com/tkw1536/goprogram/stream"
 )
 
@@ -14,11 +15,11 @@ type Backupable interface {
 	BackupName() string
 
 	// Backup backs up this component into the destination path path
-	Backup(context BackupContext) error
+	Backup(context StagingContext) error
 }
 
-// BackupContext is the context for backups
+// StagingContext represents a context for [Backupable] and [Snapshotable]
-type BackupContext interface {
+type StagingContext interface {
 	// IO returns the input output stream belonging to this backup file
 	IO() stream.IOStream
 
@@ -41,3 +42,17 @@ type BackupContext interface {
 	// AddFile will not return before op has returned.
 	AddFile(path string, op func(file io.Writer) error) error
 }
+
+// Snapshotable represents a component with a Snapshot method.
+type Snapshotable interface {
+	Component
+
+	// SnapshotNeedsRunning returns if this Snapshotable requires a running instance.
+	SnapshotNeedsRunning() bool
+
+	// SnapshotName returns a new name to be used as an argument for path.
+	SnapshotName() string
+
+	// Snapshot snapshots a part of the instance
+	Snapshot(wisski models.Instance, context StagingContext) error
+}

internal/component/control/backup.go

@@ -11,7 +11,7 @@ func (*Control) BackupName() string {
 }
 
 // Backup backups all control plane configuration files into dest
-func (control *Control) Backup(context component.BackupContext) error {
+func (control *Control) Backup(context component.StagingContext) error {
 	files := control.backupFiles()
 
 	return context.AddDirectory("", func() error {

internal/component/snapshots/snapshot_make.go

@@ -212,7 +212,7 @@ func (snapshot *Snapshot) makeBlackbox(io stream.IOStream, snapshots *Manager, i
 		defer nquads.Close()
 
 		// directly store the result
-		_, err = snapshots.TS.Snapshot(nquads, instance.GraphDBRepository)
+		_, err = snapshots.TS.SnapshotDB(nquads, instance.GraphDBRepository)
 		return err
 	}, &snapshot.ErrTriplestore)
 
@@ -233,7 +233,7 @@ func (snapshot *Snapshot) makeBlackbox(io stream.IOStream, snapshots *Manager, i
 		defer sql.Close()
 
 		// directly store the result
-		return snapshots.SQL.Snapshot(io, sql, instance.SqlDatabase)
+		return snapshots.SQL.SnapshotDB(io, sql, instance.SqlDatabase)
 	}, &snapshot.ErrSQL)
 
 	// wait for the group!

internal/component/sql/backup.go

@@ -14,7 +14,7 @@ func (*SQL) BackupName() string {
 }
 
 // Backup makes a backup of all SQL databases into the path dest.
-func (sql *SQL) Backup(context component.BackupContext) error {
+func (sql *SQL) Backup(context component.StagingContext) error {
 	return context.AddFile("", func(file io.Writer) error {
 		io := context.IO().Streams(file, nil, nil, 0).NonInteractive()
 		code, err := sql.Stack(sql.Environment).Exec(io, "sql", "mysqldump", "--all-databases")

internal/component/sql/snapshot.go

@@ -6,8 +6,8 @@ import (
 	"github.com/tkw1536/goprogram/stream"
 )
 
-// Snapshot makes a backup of the sql database into dest.
+// SnapshotDB makes a backup of the sql database into dest.
-func (sql SQL) Snapshot(io stream.IOStream, dest io.Writer, database string) error {
+func (sql SQL) SnapshotDB(io stream.IOStream, dest io.Writer, database string) error {
 	io = io.Streams(dest, nil, nil, 0).NonInteractive()
 
 	code, err := sql.Stack(sql.Environment).Exec(io, "sql", "mysqldump", "--databases", database)

internal/component/triplestore/backup.go

@@ -10,7 +10,7 @@ import (
 func (ts *Triplestore) BackupName() string { return "triplestore" }
 
 // Backup makes a backup of all Triplestore repositories databases into the path dest.
-func (ts *Triplestore) Backup(context component.BackupContext) error {
+func (ts *Triplestore) Backup(context component.StagingContext) error {
 
 	// list all the directories
 	repos, err := ts.listRepositories()
@@ -22,7 +22,7 @@ func (ts *Triplestore) Backup(context component.BackupContext) error {
 	return context.AddDirectory("", func() error {
 		for _, repo := range repos {
 			if err := context.AddFile(repo.ID+".nq", func(file io.Writer) error {
-				_, err := ts.Snapshot(file, repo.ID)
+				_, err := ts.SnapshotDB(file, repo.ID)
 				return err
 			}); err != nil {
 				return err

internal/component/triplestore/database.go

@@ -124,8 +124,8 @@ func (ts Triplestore) PurgeRepo(repo string) error {
 
 var errTSBackupWrongStatusCode = errors.New("Distillery.Backup: Wrong status code")
 
-// Snapshot snapshots the provided repository into dst
+// SnapshotDB snapshots the provided repository into dst
-func (ts Triplestore) Snapshot(dst io.Writer, repo string) (int64, error) {
+func (ts Triplestore) SnapshotDB(dst io.Writer, repo string) (int64, error) {
 	res, err := ts.OpenRaw("GET", "/repositories/"+repo+"/statements?infer=false", nil, "", "application/n-quads")
 	if err != nil {
 		return 0, err