Add initial triplestore rebuild functionality

internal/wisski/ingredient/php/extras/prefixes.go

@@ -48,7 +48,7 @@ var listURIPrefixesPHP string
 // server is an optional server to fetch prefixes from.
 // server may be nil.
 func (prefixes *Prefixes) All(ctx context.Context, server *phpx.Server) ([]string, error) {
-	uris, err := prefixes.database(ctx, server)
+	uris, err := prefixes.triplestore(ctx, server)
 	if err != nil {
 		return nil, err
 	}
@@ -61,7 +61,7 @@ func (prefixes *Prefixes) All(ctx context.Context, server *phpx.Server) ([]strin
 	return append(uris, uris2...), nil
 }
 
-func (wisski *Prefixes) database(ctx context.Context, server *phpx.Server) (prefixes []string, err error) {
+func (wisski *Prefixes) triplestore(ctx context.Context, server *phpx.Server) (prefixes []string, err error) {
 	// get all the ugly prefixes
 	err = wisski.dependencies.PHP.ExecScript(ctx, server, &prefixes, listURIPrefixesPHP, "list_prefixes")
 	if err != nil {

internal/wisski/ingredient/trb/trb.go

@@ -0,0 +1,91 @@
+package trb
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/barrel"
+	"github.com/FAU-CDI/wisski-distillery/pkg/logging"
+)
+
+type TRB struct {
+	ingredient.Base
+
+	dependencies struct {
+		Barrel *barrel.Barrel
+	}
+}
+
+func (trb *TRB) DoSomething(ctx context.Context, out io.Writer, allowEmptyRepository bool) (err error) {
+
+	// stop instance, restart when done
+	logging.LogMessage(out, "Shutting down instance")
+	if err := trb.dependencies.Barrel.Stack().Down(ctx, out); err != nil {
+		return err
+	}
+
+	defer func() {
+		logging.LogMessage(out, "Restarting instance")
+		e := trb.dependencies.Barrel.Stack().Up(ctx, out)
+		if err == nil {
+			err = e
+		}
+	}()
+
+	// make the backup
+	logging.LogMessage(out, "Dumping triplestore")
+	path, err := trb.makeBackup(ctx, allowEmptyRepository)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Wrote %q\n", path)
+
+	logging.LogMessage(out, "Purging triplestore")
+	if err := trb.Malt.TS.Purge(ctx, trb.Instance, trb.Domain()); err != nil {
+		return err
+	}
+
+	logging.LogMessage(out, "Provising triplestore")
+	if err := trb.Malt.TS.Provision(ctx, trb.Instance, trb.Domain()); err != nil {
+		return err
+	}
+
+	logging.LogMessage(out, "Loading dump file")
+	content, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer content.Close()
+
+	logging.LogMessage(out, "Restoring triplestore")
+	if err := trb.Malt.TS.RestoreDB(ctx, trb.GraphDBRepository, content); err != nil {
+		return err
+	}
+
+	return
+}
+
+var errBackupEmpty = errors.New("no data contained in backup file (is the repository empty?)")
+
+func (trb *TRB) makeBackup(ctx context.Context, allowEmptyRepository bool) (path string, err error) {
+	f, err := os.CreateTemp("", "")
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	count, err := trb.Malt.TS.SnapshotDB(ctx, f, trb.GraphDBRepository)
+	if err != nil {
+		return "", err
+	}
+
+	if count == 0 && !allowEmptyRepository {
+		return "", errBackupEmpty
+	}
+
+	return f.Name(), nil
+}

internal/wisski/wisski.go

@@ -19,6 +19,7 @@ import (
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/php/extras"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/php/users"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/reserve"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/trb"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/liquid"
 	"github.com/tkw1536/pkglib/lifetime"
 )
@@ -70,6 +71,10 @@ func (wisski *WissKI) Barrel() *barrel.Barrel {
 	return export[*barrel.Barrel](wisski)
 }
 
+func (wisski *WissKI) TRB() *trb.TRB {
+	return export[*trb.TRB](wisski)
+}
+
 func (wisski *WissKI) Manager() *manager.Manager {
 	return export[*manager.Manager](wisski)
 }
@@ -183,4 +188,5 @@ func (wisski *WissKI) allIngredients(context *lifetime.Registry[ingredient.Ingre
 	lifetime.Place[*reserve.Reserve](context)
 
 	lifetime.Place[*ssh.SSH](context)
+	lifetime.Place[*trb.TRB](context)
 }