Move wisski instance code to separate package

internal/component/home/public.go

@@ -7,8 +7,8 @@ import (
 
 	_ "embed"
 
-	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/static"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski"
 	"github.com/FAU-CDI/wisski-distillery/pkg/timex"
 	"github.com/tkw1536/goprogram/stream"
 	"golang.org/x/sync/errgroup"
@@ -65,7 +65,7 @@ func (home *Home) homeRender() ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	context.Instances = make([]instances.WissKIInfo, len(wissKIs))
+	context.Instances = make([]wisski.WissKIInfo, len(wissKIs))
 
 	// determine their infos
 	var eg errgroup.Group
@@ -86,7 +86,7 @@ func (home *Home) homeRender() ([]byte, error) {
 }
 
 type HomeContext struct {
-	Instances []instances.WissKIInfo
+	Instances []wisski.WissKIInfo
 
 	Time time.Time
 

internal/component/info/index.go

@@ -6,10 +6,10 @@ import (
 
 	_ "embed"
 
-	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/static"
 	"github.com/FAU-CDI/wisski-distillery/internal/config"
 	"github.com/FAU-CDI/wisski-distillery/internal/models"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski"
 	"golang.org/x/sync/errgroup"
 )
 
@@ -22,7 +22,7 @@ type indexPageContext struct {
 
 	Config *config.Config
 
-	Instances []instances.WissKIInfo
+	Instances []wisski.WissKIInfo
 
 	TotalCount   int
 	RunningCount int
@@ -42,7 +42,7 @@ func (info *Info) indexPageAPI(r *http.Request) (idx indexPageContext, err error
 		}
 
 		// get all of their info!
-		idx.Instances = make([]instances.WissKIInfo, len(all))
+		idx.Instances = make([]wisski.WissKIInfo, len(all))
 		for i, instance := range all {
 			{
 				i := i
@@ -61,7 +61,7 @@ func (info *Info) indexPageAPI(r *http.Request) (idx indexPageContext, err error
 
 	// get the log entries
 	group.Go(func() (err error) {
-		idx.Backups, err = info.Instances.ExportLogFor("")
+		idx.Backups, err = info.SnapshotsLog.For("")
 		return
 	})
 

internal/component/info/info.go

@@ -7,6 +7,7 @@ import (
 	"github.com/FAU-CDI/wisski-distillery/internal/component"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/snapshots"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/snapshotslog"
 	"github.com/FAU-CDI/wisski-distillery/pkg/httpx"
 	"github.com/tkw1536/goprogram/stream"
 )
@@ -16,6 +17,7 @@ type Info struct {
 
 	SnapshotManager *snapshots.Manager
 	Instances       *instances.Instances
+	SnapshotsLog    *snapshotslog.SnapshotsLog
 }
 
 func (Info) Name() string { return "control-info" }

internal/component/info/instance.go

@@ -9,6 +9,7 @@ import (
 	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/static"
 	"github.com/FAU-CDI/wisski-distillery/internal/models"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski"
 	"github.com/FAU-CDI/wisski-distillery/pkg/httpx"
 )
 
@@ -20,7 +21,7 @@ type instancePageContext struct {
 	Time time.Time
 
 	Instance models.Instance
-	Info     instances.WissKIInfo
+	Info     wisski.WissKIInfo
 }
 
 func (info *Info) instancePageAPI(r *http.Request) (is instancePageContext, err error) {

internal/component/info/socket.go

@@ -1,34 +1,34 @@
 package info
 
 import (
-	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/snapshots"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski"
 	"github.com/FAU-CDI/wisski-distillery/pkg/httpx"
 	"github.com/tkw1536/goprogram/status"
 	"github.com/tkw1536/goprogram/stream"
 )
 
-type instanceActionFunc = func(info *Info, instance instances.WissKI, str stream.IOStream) error
+type instanceActionFunc = func(info *Info, instance *wisski.WissKI, str stream.IOStream) error
 
 var socketInstanceActions = map[string]instanceActionFunc{
-	"snapshot": func(info *Info, instance instances.WissKI, str stream.IOStream) error {
+	"snapshot": func(info *Info, instance *wisski.WissKI, str stream.IOStream) error {
 		return info.SnapshotManager.MakeExport(
 			str,
 			snapshots.ExportTask{
 				Dest:     "",
-				Instance: &instance,
+				Instance: instance,
 
 				StagingOnly: false,
 			},
 		)
 	},
-	"rebuild": func(_ *Info, instance instances.WissKI, str stream.IOStream) error {
+	"rebuild": func(_ *Info, instance *wisski.WissKI, str stream.IOStream) error {
 		return instance.Build(str, true)
 	},
-	"update": func(_ *Info, instance instances.WissKI, str stream.IOStream) error {
+	"update": func(_ *Info, instance *wisski.WissKI, str stream.IOStream) error {
 		return instance.BlindUpdate(str)
 	},
-	"cron": func(_ *Info, instance instances.WissKI, str stream.IOStream) error {
+	"cron": func(_ *Info, instance *wisski.WissKI, str stream.IOStream) error {
 		return instance.Cron(str)
 	},
 }

internal/component/instances/create.go

@@ -0,0 +1,65 @@
+package instances
+
+import (
+	"errors"
+	"path/filepath"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski"
+	"github.com/FAU-CDI/wisski-distillery/pkg/stringparser"
+)
+
+var errInvalidSlug = errors.New("not a valid slug")
+
+// Create fills the struct for a new WissKI instance.
+// It validates that slug is a valid name for an instance.
+//
+// It does not perform any checks if the instance already exists, or does the creation in the database.
+func (instances *Instances) Create(slug string) (wissKI *wisski.WissKI, err error) {
+
+	// make sure that the slug is valid!
+	slug, err = stringparser.ParseSlug(instances.Environment, slug)
+	if err != nil {
+		return nil, errInvalidSlug
+	}
+
+	wissKI = new(wisski.WissKI)
+	instances.use(wissKI)
+
+	wissKI.Instance.Slug = slug
+	wissKI.Instance.FilesystemBase = filepath.Join(instances.Path(), wissKI.Domain())
+
+	wissKI.Instance.OwnerEmail = ""
+	wissKI.Instance.AutoBlindUpdateEnabled = true
+
+	// sql
+
+	wissKI.Instance.SqlDatabase = instances.Config.MysqlDatabasePrefix + slug
+	wissKI.Instance.SqlUsername = instances.Config.MysqlUserPrefix + slug
+
+	wissKI.Instance.SqlPassword, err = instances.Config.NewPassword()
+	if err != nil {
+		return nil, err
+	}
+
+	// triplestore
+
+	wissKI.Instance.GraphDBRepository = instances.Config.GraphDBRepoPrefix + slug
+	wissKI.Instance.GraphDBUsername = instances.Config.GraphDBUserPrefix + slug
+
+	wissKI.Instance.GraphDBPassword, err = instances.Config.NewPassword()
+	if err != nil {
+		return nil, err
+	}
+
+	// drupal
+
+	wissKI.DrupalUsername = "admin" // TODO: Change this!
+
+	wissKI.DrupalPassword, err = instances.Config.NewPassword()
+	if err != nil {
+		return nil, err
+	}
+
+	// store the instance in the object and return it!
+	return wissKI, nil
+}

internal/component/instances/instances.go

@@ -5,9 +5,12 @@ import (
 	"path/filepath"
 
 	"github.com/FAU-CDI/wisski-distillery/internal/component"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/meta"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/snapshotslog"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/sql"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/triplestore"
 	"github.com/FAU-CDI/wisski-distillery/internal/models"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski"
 	"github.com/tkw1536/goprogram/exit"
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
@@ -17,8 +20,10 @@ import (
 type Instances struct {
 	component.ComponentBase
 
-	TS  *triplestore.Triplestore
-	SQL *sql.SQL
+	TS           *triplestore.Triplestore
+	SQL          *sql.SQL
+	Meta         *meta.Meta
+	SnapshotsLog *snapshotslog.SnapshotsLog
 }
 
 func (Instances) Name() string {
@@ -37,40 +42,53 @@ var errSQL = exit.Error{
 	ExitCode: exit.ExitGeneric,
 }
 
-// Instance is a convenience function to return an instance based on a model slug.
-// When the instance does not exist, returns nil.
-func (instances *Instances) Instance(instance models.Instance) *WissKI {
-	i, err := instances.WissKI(instance.Slug)
-	if err != nil {
-		return nil
-	}
-	return &i
+// use uses the non-nil wisski instance with this instances
+func (instances *Instances) use(wisski *wisski.WissKI) {
+	wisski.Core = instances.Core
+	wisski.SQL = instances.SQL
+	wisski.TS = instances.TS
+	wisski.Meta = instances.Meta
+	wisski.SnapshotsLog = instances.SnapshotsLog
 }
 
 // WissKI returns the WissKI with the provided slug, if it exists.
 // It the WissKI does not exist, returns ErrWissKINotFound.
-func (instances *Instances) WissKI(slug string) (i WissKI, err error) {
+func (instances *Instances) WissKI(slug string) (wissKI *wisski.WissKI, err error) {
 	sql := instances.SQL
 	if err := sql.WaitQueryTable(); err != nil {
-		return i, err
+		return nil, err
 	}
 
 	table, err := sql.QueryTable(false, models.InstanceTable)
 	if err != nil {
-		return i, err
+		return nil, err
 	}
 
+	// create a struct
+	wissKI = new(wisski.WissKI)
+
 	// find the instance by slug
-	query := table.Where(&models.Instance{Slug: slug}).Find(&i.Instance)
+	query := table.Where(&models.Instance{Slug: slug}).Find(&wissKI.Instance)
 	switch {
 	case query.Error != nil:
-		return i, errSQL.WithMessageF(query.Error)
+		return nil, errSQL.WithMessageF(query.Error)
 	case query.RowsAffected == 0:
-		return i, ErrWissKINotFound
-	default:
-		i.instances = instances
-		return i, nil
+		return nil, ErrWissKINotFound
 	}
+
+	// use the wissKI instance
+	instances.use(wissKI)
+	return wissKI, nil
+}
+
+// Instance is a convenience function to return an instance based on a model slug.
+// When the instance does not exist, returns nil.
+func (instances *Instances) Instance(instance models.Instance) *wisski.WissKI {
+	wissKI, err := instances.WissKI(instance.Slug)
+	if err != nil {
+		return nil
+	}
+	return wissKI
 }
 
 // Has checks if a WissKI with the provided slug exists inside the database.
@@ -96,7 +114,7 @@ func (instances *Instances) Has(slug string) (ok bool, err error) {
 // All returns all instances of the WissKI Distillery in consistent order.
 //
 // There is no guarantee that this order remains identical between different api releases; however subsequent invocations are guaranteed to return the same order.
-func (instances *Instances) All() ([]WissKI, error) {
+func (instances *Instances) All() ([]*wisski.WissKI, error) {
 	return instances.find(true, func(table *gorm.DB) *gorm.DB {
 		return table
 	})
@@ -104,14 +122,14 @@ func (instances *Instances) All() ([]WissKI, error) {
 
 // WissKIs returns the WissKI instances with the provides slugs.
 // If a slug does not exist, it is omitted from the result.
-func (instances *Instances) WissKIs(slugs ...string) ([]WissKI, error) {
+func (instances *Instances) WissKIs(slugs ...string) ([]*wisski.WissKI, error) {
 	return instances.find(true, func(table *gorm.DB) *gorm.DB {
 		return table.Where("slug IN ?", slugs)
 	})
 }
 
 // Load is like All, except that when no slugs are provided, it calls All.
-func (instances *Instances) Load(slugs ...string) ([]WissKI, error) {
+func (instances *Instances) Load(slugs ...string) ([]*wisski.WissKI, error) {
 	if len(slugs) == 0 {
 		return instances.All()
 	}
@@ -119,7 +137,7 @@ func (instances *Instances) Load(slugs ...string) ([]WissKI, error) {
 }
 
 // find finds instances based on the provided query
-func (instances *Instances) find(order bool, query func(table *gorm.DB) *gorm.DB) (results []WissKI, err error) {
+func (instances *Instances) find(order bool, query func(table *gorm.DB) *gorm.DB) (results []*wisski.WissKI, err error) {
 	sql := instances.SQL
 	if err := sql.WaitQueryTable(); err != nil {
 		return nil, err
@@ -148,10 +166,11 @@ func (instances *Instances) find(order bool, query func(table *gorm.DB) *gorm.DB
 	}
 
 	// make proper instances
-	results = make([]WissKI, len(bks))
+	results = make([]*wisski.WissKI, len(bks))
 	for i, bk := range bks {
+		results[i] = new(wisski.WissKI)
 		results[i].Instance = bk
-		results[i].instances = instances
+		instances.use(results[i])
 	}
 
 	return results, nil

internal/component/instances/wisski_create.go

@@ -1,111 +0,0 @@
-package instances
-
-import (
-	"errors"
-	"path/filepath"
-	"strings"
-
-	"github.com/FAU-CDI/wisski-distillery/pkg/stringparser"
-	"github.com/alessio/shellescape"
-	"github.com/tkw1536/goprogram/stream"
-)
-
-var errInvalidSlug = errors.New("not a valid slug")
-
-// Create fills the struct for a new WissKI instance.
-// It validates that slug is a valid name for an instance.
-//
-// It does not perform any checks if the instance already exists, or does the creation in the database.
-func (instances *Instances) Create(slug string) (wisski WissKI, err error) {
-	wisski.instances = instances
-
-	// make sure that the slug is valid!
-	slug, err = stringparser.ParseSlug(instances.Environment, slug)
-	if err != nil {
-		return wisski, errInvalidSlug
-	}
-
-	wisski.Instance.Slug = slug
-	wisski.Instance.FilesystemBase = filepath.Join(instances.Path(), wisski.Domain())
-
-	wisski.Instance.OwnerEmail = ""
-	wisski.Instance.AutoBlindUpdateEnabled = true
-
-	// sql
-
-	wisski.Instance.SqlDatabase = instances.Config.MysqlDatabasePrefix + slug
-	wisski.Instance.SqlUsername = instances.Config.MysqlUserPrefix + slug
-
-	wisski.Instance.SqlPassword, err = instances.Config.NewPassword()
-	if err != nil {
-		return WissKI{}, err
-	}
-
-	// triplestore
-
-	wisski.Instance.GraphDBRepository = instances.Config.GraphDBRepoPrefix + slug
-	wisski.Instance.GraphDBUsername = instances.Config.GraphDBUserPrefix + slug
-
-	wisski.Instance.GraphDBPassword, err = instances.Config.NewPassword()
-	if err != nil {
-		return WissKI{}, err
-	}
-
-	// drupal
-
-	wisski.DrupalUsername = "admin" // TODO: Change this!
-
-	wisski.DrupalPassword, err = instances.Config.NewPassword()
-	if err != nil {
-		return wisski, err
-	}
-
-	// store the instance in the object and return it!
-	return wisski, nil
-}
-
-// Provision provisions an instance, assuming that the required databases already exist.
-func (wisski *WissKI) Provision(io stream.IOStream) error {
-
-	// build the container
-	if err := wisski.Build(io, false); err != nil {
-		return err
-	}
-
-	provisionParams := []string{
-		wisski.Domain(),
-
-		wisski.SqlDatabase,
-		wisski.SqlUsername,
-		wisski.SqlPassword,
-
-		wisski.GraphDBRepository,
-		wisski.GraphDBUsername,
-		wisski.GraphDBPassword,
-
-		wisski.DrupalUsername,
-		wisski.DrupalPassword,
-
-		"", // TODO: DrupalVersion
-		"", // TODO: WissKIVersion
-	}
-
-	// escape the parameter
-	for i, param := range provisionParams {
-		provisionParams[i] = shellescape.Quote(param)
-	}
-
-	// figure out the provision script
-	// TODO: Move the provision script into the control plane!
-	provisionScript := "sudo PATH=$PATH -u www-data /bin/bash /provision_container.sh " + strings.Join(provisionParams, " ")
-
-	code, err := wisski.Barrel().Run(io, true, "barrel", "/bin/bash", "-c", provisionScript)
-	if err != nil {
-		return err
-	}
-	if code != 0 {
-		return errors.New("unable to run provision script")
-	}
-
-	return nil
-}

internal/component/instances/wisski_db.go

@@ -1,48 +0,0 @@
-package instances
-
-import "github.com/FAU-CDI/wisski-distillery/internal/models"
-
-// WissKI represents a single WissKI Instance
-type WissKI struct {
-	// Whatever is stored inside the bookkeeping database
-	models.Instance
-
-	// Credentials to Drupal
-	DrupalUsername string
-	DrupalPassword string
-
-	// reference to the component!
-	instances *Instances
-}
-
-// Save saves this instance in the bookkeeping table
-func (wisski *WissKI) Save() error {
-	db, err := wisski.instances.SQL.QueryTable(false, models.InstanceTable)
-	if err != nil {
-		return err
-	}
-
-	// it has never been created => we need to create it in the database
-	if wisski.Instance.Created.IsZero() {
-		return db.Create(&wisski.Instance).Error
-	}
-
-	// Update based on the primary key!
-	return db.Where("pk = ?", wisski.Instance.Pk).Updates(&wisski.Instance).Error
-}
-
-// Delete deletes this instance from the bookkeeping table
-func (wisski *WissKI) Delete() error {
-	db, err := wisski.instances.SQL.QueryTable(false, models.InstanceTable)
-	if err != nil {
-		return err
-	}
-
-	// doesn't exist => nothing to delete
-	if wisski.Instance.Created.IsZero() {
-		return nil
-	}
-
-	// delete it directly
-	return db.Delete(&wisski.Instance).Error
-}

internal/component/instances/wisski_exec.go

@@ -1,10 +0,0 @@
-package instances
-
-import (
-	"github.com/tkw1536/goprogram/stream"
-)
-
-// Shell executes a shell command inside the instance.
-func (wisski *WissKI) Shell(io stream.IOStream, argv ...string) (int, error) {
-	return wisski.Barrel().Exec(io, "barrel", "/bin/sh", append([]string{"/user_shell.sh"}, argv...)...)
-}

internal/component/meta/meta.go

@@ -0,0 +1,44 @@
+package meta
+
+import (
+	"sync"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/component"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/sql"
+)
+
+// Component meta is responsible for managing metadata per WissKI Instance
+type Meta struct {
+	component.ComponentBase
+
+	SQL *sql.SQL
+
+	sl sync.Mutex
+	sc map[string]*Storage
+}
+
+func (*Meta) Name() string { return "metadata" }
+
+// Storage returns a Storage for the instance with the given slug.
+// When slug is nil, returns a global storage.
+func (meta *Meta) Storage(slug string) *Storage {
+	meta.sl.Lock()
+	defer meta.sl.Unlock()
+
+	// create the cache (unless it already exists)
+	if meta.sc == nil {
+		meta.sc = make(map[string]*Storage)
+	}
+
+	// cache hit
+	if storage, ok := meta.sc[slug]; ok {
+		return storage
+	}
+
+	// create a new storage
+	meta.sc[slug] = &Storage{
+		Slug: slug,
+		sql:  meta.SQL,
+	}
+	return meta.sc[slug]
+}

internal/component/meta/provision.go

@@ -0,0 +1,14 @@
+package meta
+
+import "github.com/FAU-CDI/wisski-distillery/internal/models"
+
+// Provision provisions new meta storage for this instance.
+// NOTE(twiesing): This is a no-op, because we implement Purge.
+func (meta *Meta) Provision(instance models.Instance, domain string) error {
+	return nil
+}
+
+// Purge purges the storage for the given instance.
+func (meta *Meta) Purge(instance models.Instance, domain string) error {
+	return meta.Storage(instance.Slug).Purge()
+}

internal/component/meta/storage.go

@@ -1,4 +1,4 @@
-package instances
+package meta
 
 import (
 	"encoding/json"
@@ -6,68 +6,26 @@ import (
 
 	"github.com/FAU-CDI/wisski-distillery/internal/component/sql"
 	"github.com/FAU-CDI/wisski-distillery/internal/models"
+	"github.com/tkw1536/goprogram/lib/collection"
 	"gorm.io/gorm"
 )
 
-// MetaKey represents a key for metadata.
-type MetaKey string
+// Key represents a key for metadata.
+type Key string
 
 // ErrMetadatumNotSet is returned by various [MetaStorage] functions when a metadatum is not set
 var ErrMetadatumNotSet = errors.New("metadatum not set")
 
-// MetaStorage manages some metadata.
-type MetaStorage interface {
-	// Get retrieves metadata with the provided key and deserializes the first one into target.
-	// If no metadatum exists, returns [ErrMetadatumNotSet].
-	Get(key MetaKey, target any) error
-
-	// GetAll receives all metadata with the provided keys.
-	// For each received value, the targets function is called with the current index, and total number of results.
-	// The function is intended to return a target for deserialization.
-	//
-	// When no metadatum exists, targets is not called, and nil error is returned.
-	GetAll(key MetaKey, targets func(index, total int) any) error
-
-	// Delete deletes all metadata with the provided key.
-	Delete(key MetaKey) error
-
-	// Set serializes value and stores it with the provided key.
-	// Any other metadata with the same key is deleted.
-	Set(key MetaKey, value any) error
-
-	// Set serializes values and stores them with the provided key.
-	// Any other metadata with the same key is deleted.
-	SetAll(key MetaKey, values ...any) error
-
-	// Purge removes all metadata, regardless of key.
-	Purge() error
-}
-
-// Metadata returns a system-wide [MetaStorage].
-func (instances *Instances) Metadata() MetaStorage {
-	return &storage{
-		SQL:  instances.SQL,
-		Slug: "", // not associated to any slug
-	}
-}
-
-// Metadata returns a [MetaStorage] that manages metadata related to this WissKI instance.
-// It will be automatically deleted once the instance is deleted.
-func (wisski *WissKI) Metadata() MetaStorage {
-	return &storage{
-		SQL:  wisski.instances.SQL,
-		Slug: wisski.Slug, // associated to this instance
-	}
-}
-
-// storage implements MetaStorage
-type storage struct {
-	SQL  *sql.SQL
+// Storage manages metadata for either the entire distillery, or a single slug
+type Storage struct {
 	Slug string
+	sql  *sql.SQL
 }
 
-func (s *storage) Get(key MetaKey, target any) error {
-	table, err := s.SQL.QueryTable(true, models.MetadataTable)
+// Get retrieves metadata with the provided key and deserializes the first one into target.
+// If no metadatum exists, returns [ErrMetadatumNotSet].
+func (s Storage) Get(key Key, target any) error {
+	table, err := s.sql.QueryTable(true, models.MetadataTable)
 	if err != nil {
 		return err
 	}
@@ -90,8 +48,13 @@ func (s *storage) Get(key MetaKey, target any) error {
 	return json.Unmarshal(datum.Value, target)
 }
 
-func (s *storage) GetAll(key MetaKey, target func(index, total int) any) error {
-	table, err := s.SQL.QueryTable(true, models.MetadataTable)
+// GetAll receives all metadata with the provided keys.
+// For each received value, the targets function is called with the current index, and total number of results.
+// The function is intended to return a target for deserialization.
+//
+// When no metadatum exists, targets is not called, and nil error is returned.
+func (s Storage) GetAll(key Key, target func(index, total int) any) error {
+	table, err := s.sql.QueryTable(true, models.MetadataTable)
 	if err != nil {
 		return err
 	}
@@ -116,8 +79,9 @@ func (s *storage) GetAll(key MetaKey, target func(index, total int) any) error {
 	return nil
 }
 
-func (s *storage) Delete(key MetaKey) error {
-	table, err := s.SQL.QueryTable(true, models.MetadataTable)
+// Delete deletes all metadata with the provided key.
+func (s Storage) Delete(key Key) error {
+	table, err := s.sql.QueryTable(true, models.MetadataTable)
 	if err != nil {
 		return err
 	}
@@ -130,8 +94,10 @@ func (s *storage) Delete(key MetaKey) error {
 	return nil
 }
 
-func (s *storage) Set(key MetaKey, value any) error {
-	table, err := s.SQL.QueryTable(true, models.MetadataTable)
+// Set serializes value and stores it with the provided key.
+// Any other metadata with the same key is deleted.
+func (s Storage) Set(key Key, value any) error {
+	table, err := s.sql.QueryTable(true, models.MetadataTable)
 	if err != nil {
 		return err
 	}
@@ -163,8 +129,10 @@ func (s *storage) Set(key MetaKey, value any) error {
 	})
 }
 
-func (s *storage) SetAll(key MetaKey, values ...any) error {
-	table, err := s.SQL.QueryTable(true, models.MetadataTable)
+// Set serializes values and stores them with the provided key.
+// Any other metadata with the same key is deleted.
+func (s Storage) SetAll(key Key, values ...any) error {
+	table, err := s.sql.QueryTable(true, models.MetadataTable)
 	if err != nil {
 		return err
 	}
@@ -196,8 +164,9 @@ func (s *storage) SetAll(key MetaKey, values ...any) error {
 	})
 }
 
-func (s *storage) Purge() error {
-	table, err := s.SQL.QueryTable(true, models.MetadataTable)
+// Purge removes all metadata, regardless of key.
+func (s Storage) Purge() error {
+	table, err := s.sql.QueryTable(true, models.MetadataTable)
 	if err != nil {
 		return err
 	}
@@ -208,3 +177,42 @@ func (s *storage) Purge() error {
 	}
 	return nil
 }
+
+// StorageFor returns a storage for the given key.
+func StorageFor[Value any](key Key) func(storage *Storage) SpecifcStorage[Value] {
+	return func(storage *Storage) SpecifcStorage[Value] {
+		return SpecifcStorage[Value]{storage: storage, key: key}
+	}
+}
+
+type SpecifcStorage[Value any] struct {
+	storage *Storage
+	key     Key
+}
+
+func (sf SpecifcStorage[Value]) Get() (value Value, err error) {
+	err = sf.storage.Get(sf.key, &value)
+	return
+}
+
+func (sf SpecifcStorage[Value]) GetAll() (values []Value, err error) {
+	err = sf.storage.GetAll(sf.key, func(index, total int) any {
+		if values == nil {
+			values = make([]Value, total)
+		}
+		return &values[index]
+	})
+	return values, err
+}
+
+func (sf SpecifcStorage[Value]) Set(value Value) error {
+	return sf.storage.Set(sf.key, value)
+}
+
+func (sf SpecifcStorage[Value]) SetAll(values ...Value) error {
+	return sf.storage.SetAll(sf.key, collection.AsAny(values)...)
+}
+
+func (sf SpecifcStorage[Value]) Delete() error {
+	return sf.storage.Delete(sf.key)
+}

internal/component/snapshots/backup.go

@@ -7,7 +7,7 @@ import (
 	"time"
 
 	"github.com/FAU-CDI/wisski-distillery/internal/component"
-	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski"
 
 	"github.com/FAU-CDI/wisski-distillery/pkg/environment"
 	"github.com/FAU-CDI/wisski-distillery/pkg/logging"
@@ -131,13 +131,13 @@ func (backup *Backup) run(ios stream.IOStream, manager *Manager) {
 		}
 
 		// make a backup of the snapshots
-		backup.InstanceSnapshots = status.Group[instances.WissKI, Snapshot]{
-			PrefixString: func(item instances.WissKI, index int) string {
+		backup.InstanceSnapshots = status.Group[*wisski.WissKI, Snapshot]{
+			PrefixString: func(item *wisski.WissKI, index int) string {
 				return fmt.Sprintf("[snapshot %q]: ", item.Slug)
 			},
 			PrefixAlign: true,
 
-			Handler: func(instance instances.WissKI, index int, writer io.Writer) Snapshot {
+			Handler: func(instance *wisski.WissKI, index int, writer io.Writer) Snapshot {
 				dir := filepath.Join(instancesBackupDir, instance.Slug)
 				if err := manager.Environment.Mkdir(dir, environment.DefaultDirPerm); err != nil {
 					return Snapshot{
@@ -151,10 +151,10 @@ func (backup *Backup) run(ios stream.IOStream, manager *Manager) {
 					Dest: dir,
 				})
 			},
-			ResultString: func(res Snapshot, item instances.WissKI, index int) string {
+			ResultString: func(res Snapshot, item *wisski.WissKI, index int) string {
 				return "done"
 			},
-			WaitString:   status.DefaultWaitString[instances.WissKI],
+			WaitString:   status.DefaultWaitString[*wisski.WissKI],
 			HandlerLimit: backup.Description.ConcurrentSnapshots,
 		}.Use(st, wissKIs)
 

internal/component/snapshots/iface.go

@@ -4,8 +4,8 @@ import (
 	"io"
 	"path/filepath"
 
-	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
 	"github.com/FAU-CDI/wisski-distillery/internal/models"
+	"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/FAU-CDI/wisski-distillery/pkg/targz"
@@ -26,7 +26,7 @@ type ExportTask struct {
 
 	// Instance is the instance to generate a snapshot of.
 	// To generate a backup, leave this to be nil.
-	Instance *instances.WissKI
+	Instance *wisski.WissKI
 
 	// BackupDescriptions and SnapshotDescriptions further specitfy options for the export.
 	// The Dest parameter is ignored, and updated automatically.
@@ -99,7 +99,7 @@ func (manager *Manager) MakeExport(io stream.IOStream, task ExportTask) (err err
 			sl = &backup
 		} else {
 			task.SnapshotDescription.Dest = stagingDir
-			snapshot := manager.NewSnapshot(*task.Instance, io, task.SnapshotDescription)
+			snapshot := manager.NewSnapshot(task.Instance, io, task.SnapshotDescription)
 			sl = &snapshot
 		}
 
@@ -131,7 +131,7 @@ func (manager *Manager) MakeExport(io stream.IOStream, task ExportTask) (err err
 		// write out the log entry
 		entry.Path = stagingDir
 		entry.Packed = false
-		manager.Instances.AddToExportLog(entry)
+		manager.SnapshotsLog.Add(entry)
 
 		io.Printf("Wrote %s\n", stagingDir)
 		return nil
@@ -159,7 +159,7 @@ func (manager *Manager) MakeExport(io stream.IOStream, task ExportTask) (err err
 	logging.LogMessage(io, "Writing Log Entry")
 	entry.Path = archivePath
 	entry.Packed = true
-	manager.Instances.AddToExportLog(entry)
+	manager.SnapshotsLog.Add(entry)
 
 	// and we're done!
 	return nil

internal/component/snapshots/manager.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/FAU-CDI/wisski-distillery/internal/component"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/snapshotslog"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/sql"
 	"github.com/FAU-CDI/wisski-distillery/pkg/environment"
 	"github.com/FAU-CDI/wisski-distillery/pkg/fsx"
@@ -17,8 +18,9 @@ import (
 type Manager struct {
 	component.ComponentBase
 
-	SQL       *sql.SQL
-	Instances *instances.Instances
+	SQL          *sql.SQL
+	Instances    *instances.Instances
+	SnapshotsLog *snapshotslog.SnapshotsLog
 
 	Snapshotable []component.Snapshotable
 	Backupable   []component.Backupable

internal/component/snapshots/prune.go

@@ -50,6 +50,6 @@ func (manager *Manager) PruneExports(io stream.IOStream) error {
 	}
 
 	// prune the snapshot log!
-	_, err = manager.Instances.ExportLog()
+	_, err = manager.SnapshotsLog.Log()
 	return err
 }

internal/component/snapshots/snapshot.go

@@ -7,8 +7,8 @@ import (
 	"time"
 
 	"github.com/FAU-CDI/wisski-distillery/internal/component"
-	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
 	"github.com/FAU-CDI/wisski-distillery/internal/models"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski"
 	"github.com/FAU-CDI/wisski-distillery/pkg/logging"
 	"github.com/tkw1536/goprogram/lib/collection"
 	"github.com/tkw1536/goprogram/status"
@@ -43,7 +43,7 @@ type Snapshot struct {
 }
 
 // Snapshot creates a new snapshot of this instance into dest
-func (snapshots *Manager) NewSnapshot(instance instances.WissKI, io stream.IOStream, desc SnapshotDescription) (snapshot Snapshot) {
+func (snapshots *Manager) NewSnapshot(instance *wisski.WissKI, io stream.IOStream, desc SnapshotDescription) (snapshot Snapshot) {
 
 	logging.LogMessage(io, "Locking instance")
 	if err := instance.TryLock(); err != nil {
@@ -83,7 +83,7 @@ func (snapshots *Manager) NewSnapshot(instance instances.WissKI, io stream.IOStr
 	return
 }
 
-func (snapshot *Snapshot) makeParts(ios stream.IOStream, snapshots *Manager, instance instances.WissKI, needsRunning bool) map[string]error {
+func (snapshot *Snapshot) makeParts(ios stream.IOStream, snapshots *Manager, instance *wisski.WissKI, needsRunning bool) map[string]error {
 	if !needsRunning && !snapshot.Description.Keepalive {
 		stack := instance.Barrel()
 

internal/component/snapshotslog/snapshotslog.go

@@ -1,16 +1,27 @@
-package instances
+package snapshotslog
 
 import (
+	"github.com/FAU-CDI/wisski-distillery/internal/component"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/sql"
 	"github.com/FAU-CDI/wisski-distillery/internal/models"
 	"github.com/FAU-CDI/wisski-distillery/pkg/environment"
 	"github.com/tkw1536/goprogram/lib/collection"
 )
 
-// ExportLogFor retrieves (and prunes) the ExportLog.
+// SnapshotsLog is responsible for logging snapshots
+type SnapshotsLog struct {
+	component.ComponentBase
+
+	SQL *sql.SQL
+}
+
+func (*SnapshotsLog) Name() string { return "snapshots-log" }
+
+// For retrieves (and prunes) the ExportLog.
 // Slug determines if entries for Backups (empty slug)
 // or a specific Instance (non-empty slug) are returned.
-func (instances *Instances) ExportLogFor(slug string) (exports []models.Export, err error) {
-	exports, err = instances.ExportLog()
+func (log *SnapshotsLog) For(slug string) (exports []models.Export, err error) {
+	exports, err = log.Log()
 	if err != nil {
 		return nil, err
 	}
@@ -20,10 +31,10 @@ func (instances *Instances) ExportLogFor(slug string) (exports []models.Export,
 	}), nil
 }
 
-// ExportLog retrieves (and prunes) all entries in the snapshot log.
-func (instances *Instances) ExportLog() ([]models.Export, error) {
+// Log retrieves (and prunes) all entries in the snapshot log.
+func (log *SnapshotsLog) Log() ([]models.Export, error) {
 	// query the table!
-	table, err := instances.SQL.QueryTable(false, models.ExportTable)
+	table, err := log.SQL.QueryTable(false, models.ExportTable)
 	if err != nil {
 		return nil, err
 	}
@@ -37,7 +48,7 @@ func (instances *Instances) ExportLog() ([]models.Export, error) {
 
 	// partition out the exports that have been deleted!
 	parts := collection.Partition(exports, func(s models.Export) bool {
-		_, err := instances.Core.Environment.Stat(s.Path)
+		_, err := log.Core.Environment.Stat(s.Path)
 		return !environment.IsNotExist(err)
 	})
 
@@ -52,15 +63,10 @@ func (instances *Instances) ExportLog() ([]models.Export, error) {
 	return parts[true], nil
 }
 
-// Snapshots returns the list of snapshots of this WissKI
-func (wisski *WissKI) Snapshots() (snapshots []models.Export, err error) {
-	return wisski.instances.ExportLogFor(wisski.Slug)
-}
-
 // AddToExportLog adds the provided export to the log.
-func (instances *Instances) AddToExportLog(export models.Export) error {
+func (log *SnapshotsLog) Add(export models.Export) error {
 	// find the table
-	table, err := instances.SQL.QueryTable(false, models.ExportTable)
+	table, err := log.SQL.QueryTable(false, models.ExportTable)
 	if err != nil {
 		return err
 	}

internal/dis/component.go

@@ -8,61 +8,72 @@ import (
 	"github.com/FAU-CDI/wisski-distillery/internal/component/home"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/info"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/meta"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/resolver"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/snapshots"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/snapshotslog"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/sql"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/ssh"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/static"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/triplestore"
 	"github.com/FAU-CDI/wisski-distillery/internal/component/web"
+	"github.com/tkw1536/goprogram/lib/collection"
 )
 
 // register returns all components of the distillery
 func (dis *Distillery) register(context component.ComponentPoolContext) []component.Component {
-	return []component.Component{
-		ra[*web.Web](dis, context),
+	return collection.MapSlice([]initFunc{
+		auto[*web.Web],
 
-		ra[*ssh.SSH](dis, context),
+		auto[*ssh.SSH],
 
-		r(dis, context, func(ts *triplestore.Triplestore) {
+		manual(func(ts *triplestore.Triplestore) {
 			ts.BaseURL = "http://" + dis.Upstream.Triplestore
 			ts.PollContext = dis.Context()
 			ts.PollInterval = time.Second
 		}),
-		r(dis, context, func(sql *sql.SQL) {
+		manual(func(sql *sql.SQL) {
 			sql.ServerURL = dis.Upstream.SQL
 			sql.PollContext = dis.Context()
 			sql.PollInterval = time.Second
 		}),
 
-		ra[*instances.Instances](dis, context),
+		auto[*instances.Instances],
+		auto[*meta.Meta],
 
 		// Snapshots
-		ra[*snapshots.Manager](dis, context),
-		ra[*snapshots.Config](dis, context),
-		ra[*snapshots.Bookkeeping](dis, context),
-		ra[*snapshots.Filesystem](dis, context),
-		ra[*snapshots.Pathbuilders](dis, context),
+		auto[*snapshots.Manager],
+		auto[*snapshotslog.SnapshotsLog],
+		auto[*snapshots.Config],
+		auto[*snapshots.Bookkeeping],
+		auto[*snapshots.Filesystem],
+		auto[*snapshots.Pathbuilders],
 
 		// Control server
-		ra[*control.Control](dis, context),
-		ra[*static.Static](dis, context),
-		r(dis, context, func(home *home.Home) {
+		auto[*control.Control],
+		auto[*static.Static],
+		manual(func(home *home.Home) {
 			home.RefreshInterval = time.Minute
 		}),
-		r(dis, context, func(resolver *resolver.Resolver) {
+		manual(func(resolver *resolver.Resolver) {
 			resolver.RefreshInterval = time.Minute
 		}),
-		ra[*info.Info](dis, context),
+		auto[*info.Info],
+	}, func(f initFunc) component.Component {
+		return f(dis, context)
+	})
+}
+
+type initFunc = func(dis *Distillery, context component.ComponentPoolContext) component.Component
+
+// manual initializes a component from the provided distillery.
+func manual[C component.Component](init func(component C)) initFunc {
+	return func(dis *Distillery, context component.ComponentPoolContext) component.Component {
+		return component.MakeComponent(context, dis.Core, init)
 	}
 }
 
-// r initializes a component from the provided distillery.
-func r[C component.Component](dis *Distillery, context component.ComponentPoolContext, init func(component C)) C {
-	return component.MakeComponent(context, dis.Core, init)
-}
-
-// ra is like r, but does not provided additional initialization
-func ra[C component.Component](dis *Distillery, context component.ComponentPoolContext) C {
-	return r[C](dis, context, nil)
+// use is like r, but does not provided additional initialization
+func auto[C component.Component](dis *Distillery, context component.ComponentPoolContext) component.Component {
+	return component.MakeComponent[C](context, dis.Core, nil)
 }

internal/dis/distillery.go

@@ -85,7 +85,7 @@ func (dis *Distillery) Triplestore() *triplestore.Triplestore {
 func (dis *Distillery) Instances() *instances.Instances {
 	return e[*instances.Instances](dis)
 }
-func (dis *Distillery) SnapshotManager() *snapshots.Manager {
+func (dis *Distillery) ExportManager() *snapshots.Manager {
 	return e[*snapshots.Manager](dis)
 }
 

internal/wisski/cron.go

@@ -1,4 +1,4 @@
-package instances
+package wisski
 
 import (
 	"time"

internal/wisski/info.go

@@ -1,4 +1,4 @@
-package instances
+package wisski
 
 import (
 	"time"

internal/wisski/lock.go

@@ -1,4 +1,4 @@
-package instances
+package wisski
 
 import (
 	"errors"
@@ -10,8 +10,8 @@ var ErrLocked = errors.New("instance is locked")
 
 // TryLock attemps to lock this WissKI
 // If this is not possible, returns ErrLocked
-func (wisski WissKI) TryLock() error {
-	table, err := wisski.instances.SQL.QueryTable(true, models.LockTable)
+func (wisski *WissKI) TryLock() error {
+	table, err := wisski.SQL.QueryTable(true, models.LockTable)
 	if err != nil {
 		return ErrLocked
 	}
@@ -25,8 +25,8 @@ func (wisski WissKI) TryLock() error {
 	return nil
 }
 
-func (wisski WissKI) IsLocked() (locked bool) {
-	table, err := wisski.instances.SQL.QueryTable(true, models.LockTable)
+func (wisski *WissKI) IsLocked() (locked bool) {
+	table, err := wisski.SQL.QueryTable(true, models.LockTable)
 	if err != nil {
 		return false
 	}
@@ -38,7 +38,7 @@ func (wisski WissKI) IsLocked() (locked bool) {
 
 // Unlock unlocks this WissKI instance and returns if it succeeded
 func (wisski WissKI) Unlock() bool {
-	table, err := wisski.instances.SQL.QueryTable(true, models.LockTable)
+	table, err := wisski.SQL.QueryTable(true, models.LockTable)
 	if err != nil {
 		return false
 	}

internal/wisski/meta.go

@@ -0,0 +1,7 @@
+package wisski
+
+import "github.com/FAU-CDI/wisski-distillery/internal/component/meta"
+
+func (wisski *WissKI) storage() *meta.Storage {
+	return wisski.Meta.Storage(wisski.Slug)
+}

internal/wisski/pathbuilders.go

@@ -1,4 +1,4 @@
-package instances
+package wisski
 
 import (
 	_ "embed"

internal/wisski/php.go

@@ -1,4 +1,4 @@
-package instances
+package wisski
 
 import (
 	_ "embed"

internal/wisski/php_server.go

@@ -1,4 +1,4 @@
-package instances
+package wisski
 
 import (
 	"context"

internal/wisski/prefix.go

@@ -1,10 +1,11 @@
-package instances
+package wisski
 
 import (
 	"bufio"
 	"path/filepath"
 	"strings"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/component/meta"
 	"github.com/FAU-CDI/wisski-distillery/pkg/fsx"
 	"github.com/tkw1536/goprogram/lib/collection"
 
@@ -14,7 +15,7 @@ import (
 // NoPrefix checks if this WissKI instance is excluded from generating prefixes.
 // TODO: Move this to the database!
 func (wisski *WissKI) NoPrefix() bool {
-	return fsx.IsFile(wisski.instances.Environment, filepath.Join(wisski.FilesystemBase, "prefixes.skip"))
+	return fsx.IsFile(wisski.Core.Environment, filepath.Join(wisski.FilesystemBase, "prefixes.skip"))
 }
 
 //go:embed php/list_uri_prefixes.php
@@ -51,7 +52,7 @@ func (wisski *WissKI) dbPrefixes(server *PHPServer) (prefixes []string, err erro
 	})
 
 	// load the list of blocked prefixes
-	blocks, err := wisski.instances.blockedPrefixes()
+	blocks, err := wisski.blockedPrefixes()
 	if err != nil {
 		return nil, err
 	}
@@ -60,9 +61,9 @@ func (wisski *WissKI) dbPrefixes(server *PHPServer) (prefixes []string, err erro
 	return collection.Filter(prefixes, func(uri string) bool { return !hasAnyPrefix(uri, blocks) }), nil
 }
 
-func (instances *Instances) blockedPrefixes() ([]string, error) {
+func (wisski *WissKI) blockedPrefixes() ([]string, error) {
 	// open the resolver block file
-	file, err := instances.Environment.Open(instances.Config.SelfResolverBlockFile)
+	file, err := wisski.Core.Environment.Open(wisski.Core.Config.SelfResolverBlockFile)
 	if err != nil {
 		return nil, err
 	}
@@ -99,11 +100,11 @@ func hasAnyPrefix(candidate string, prefixes []string) bool {
 
 func (wisski *WissKI) filePrefixes() (prefixes []string, err error) {
 	path := filepath.Join(wisski.FilesystemBase, "prefixes")
-	if !fsx.IsFile(wisski.instances.Environment, path) {
+	if !fsx.IsFile(wisski.Core.Environment, path) {
 		return nil, nil
 	}
 
-	file, err := wisski.instances.Environment.Open(path)
+	file, err := wisski.Core.Environment.Open(path)
 	if err != nil {
 		return nil, err
 	}
@@ -126,17 +127,11 @@ func (wisski *WissKI) filePrefixes() (prefixes []string, err error) {
 
 // CACHING
 
-var PrefixConfigKey MetaKey = "prefix"
+var prefix = meta.StorageFor[string]("prefix")
 
 // Prefixes returns the cached prefixes from the given instance
 func (wisski *WissKI) PrefixesCached() (results []string, err error) {
-	err = wisski.Metadata().GetAll(PrefixConfigKey, func(index, total int) any {
-		if results == nil {
-			results = make([]string, total)
-		}
-		return &results[index]
-	})
-	return
+	return prefix(wisski.storage()).GetAll()
 }
 
 // UpdatePrefixes updates the cached prefixes of this instance
@@ -145,6 +140,5 @@ func (wisski *WissKI) UpdatePrefixes() error {
 	if err != nil {
 		return err
 	}
-
-	return wisski.Metadata().SetAll(PrefixConfigKey, collection.AsAny(prefixes)...)
+	return prefix(wisski.storage()).SetAll(prefixes...)
 }

internal/wisski/props.go

@@ -1,4 +1,4 @@
-package instances
+package wisski
 
 import (
 	"fmt"
@@ -7,7 +7,7 @@ import (
 
 // Domain returns the full domain name of this WissKI
 func (wisski WissKI) Domain() string {
-	return fmt.Sprintf("%s.%s", wisski.Slug, wisski.instances.Config.DefaultDomain)
+	return fmt.Sprintf("%s.%s", wisski.Slug, wisski.Core.Config.DefaultDomain)
 }
 
 // URL returns the public URL of this instance
@@ -19,7 +19,7 @@ func (wisski WissKI) URL() *url.URL {
 	}
 
 	// use http or https scheme depending on if the distillery has it enabled
-	if wisski.instances.Config.HTTPSEnabled() {
+	if wisski.Core.Config.HTTPSEnabled() {
 		url.Scheme = "https"
 	} else {
 		url.Scheme = "http"

internal/wisski/provision.go

@@ -0,0 +1,55 @@
+package wisski
+
+import (
+	"errors"
+	"strings"
+
+	"github.com/alessio/shellescape"
+	"github.com/tkw1536/goprogram/stream"
+)
+
+// Provision provisions an instance, assuming that the required databases already exist.
+func (wisski *WissKI) Provision(io stream.IOStream) error {
+
+	// build the container
+	if err := wisski.Build(io, false); err != nil {
+		return err
+	}
+
+	provisionParams := []string{
+		wisski.Domain(),
+
+		wisski.SqlDatabase,
+		wisski.SqlUsername,
+		wisski.SqlPassword,
+
+		wisski.GraphDBRepository,
+		wisski.GraphDBUsername,
+		wisski.GraphDBPassword,
+
+		wisski.DrupalUsername,
+		wisski.DrupalPassword,
+
+		"", // TODO: DrupalVersion
+		"", // TODO: WissKIVersion
+	}
+
+	// escape the parameter
+	for i, param := range provisionParams {
+		provisionParams[i] = shellescape.Quote(param)
+	}
+
+	// figure out the provision script
+	// TODO: Move the provision script into the control plane!
+	provisionScript := "sudo PATH=$PATH -u www-data /bin/bash /provision_container.sh " + strings.Join(provisionParams, " ")
+
+	code, err := wisski.Barrel().Run(io, true, "barrel", "/bin/bash", "-c", provisionScript)
+	if err != nil {
+		return err
+	}
+	if code != 0 {
+		return errors.New("unable to run provision script")
+	}
+
+	return nil
+}

internal/wisski/snapshots.go

@@ -0,0 +1,8 @@
+package wisski
+
+import "github.com/FAU-CDI/wisski-distillery/internal/models"
+
+// Snapshots returns the list of snapshots of this WissKI
+func (wisski *WissKI) Snapshots() (snapshots []models.Export, err error) {
+	return wisski.SnapshotsLog.For(wisski.Slug)
+}

internal/wisski/stack.go

@@ -1,4 +1,4 @@
-package instances
+package wisski
 
 import (
 	"embed"
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/FAU-CDI/wisski-distillery/internal/component"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/meta"
 	"github.com/tkw1536/goprogram/stream"
 )
 
@@ -17,7 +18,7 @@ func (wisski *WissKI) Barrel() component.StackWithResources {
 	return component.StackWithResources{
 		Stack: component.Stack{
 			Dir: wisski.FilesystemBase,
-			Env: wisski.instances.Environment,
+			Env: wisski.Core.Environment,
 		},
 
 		Resources:   barrelResources,
@@ -25,15 +26,15 @@ func (wisski *WissKI) Barrel() component.StackWithResources {
 		EnvPath:     filepath.Join("instances", "barrel.env"),
 
 		EnvContext: map[string]string{
-			"DOCKER_NETWORK_NAME": wisski.instances.Config.DockerNetworkName,
+			"DOCKER_NETWORK_NAME": wisski.Core.Config.DockerNetworkName,
 
 			"SLUG":          wisski.Slug,
 			"VIRTUAL_HOST":  wisski.Domain(),
-			"HTTPS_ENABLED": wisski.instances.Config.HTTPSEnabledEnv(),
+			"HTTPS_ENABLED": wisski.Core.Config.HTTPSEnabledEnv(),
 
 			"DATA_PATH":                   filepath.Join(wisski.FilesystemBase, "data"),
-			"RUNTIME_DIR":                 wisski.instances.Config.RuntimeDir(),
-			"GLOBAL_AUTHORIZED_KEYS_FILE": wisski.instances.Config.GlobalAuthorizedKeysFile,
+			"RUNTIME_DIR":                 wisski.Core.Config.RuntimeDir(),
+			"GLOBAL_AUTHORIZED_KEYS_FILE": wisski.Core.Config.GlobalAuthorizedKeysFile,
 		},
 
 		MakeDirs: []string{"data", ".composer"},
@@ -44,14 +45,12 @@ func (wisski *WissKI) Barrel() component.StackWithResources {
 	}
 }
 
-const KeyLastRebuild MetaKey = "lastRebuild"
+// TODO: Move this to time.Time
+var lastRebuild = meta.StorageFor[int64]("lastRebuild")
 
 func (wisski *WissKI) LastRebuild() (t time.Time, err error) {
-	var epoch int64
-
-	// read the epoch!
-	err = wisski.Metadata().Get(KeyLastRebuild, &epoch)
-	if err == ErrMetadatumNotSet {
+	epoch, err := lastRebuild(wisski.storage()).Get()
+	if err == meta.ErrMetadatumNotSet {
 		return t, nil
 	}
 	if err != nil {
@@ -63,7 +62,7 @@ func (wisski *WissKI) LastRebuild() (t time.Time, err error) {
 }
 
 func (wisski *WissKI) setLastRebuild() error {
-	return wisski.Metadata().Set(KeyLastRebuild, time.Now().Unix())
+	return lastRebuild(wisski.storage()).Set(time.Now().Unix())
 }
 
 // Build builds or rebuilds the barel connected to this instance.
@@ -105,7 +104,7 @@ func (wisski *WissKI) Reserve() component.StackWithResources {
 	return component.StackWithResources{
 		Stack: component.Stack{
 			Dir: wisski.FilesystemBase,
-			Env: wisski.instances.Environment,
+			Env: wisski.Core.Environment,
 		},
 
 		Resources:   reserveResources,
@@ -113,11 +112,16 @@ func (wisski *WissKI) Reserve() component.StackWithResources {
 		EnvPath:     filepath.Join("instances", "reserve.env"),
 
 		EnvContext: map[string]string{
-			"DOCKER_NETWORK_NAME": wisski.instances.Config.DockerNetworkName,
+			"DOCKER_NETWORK_NAME": wisski.Core.Config.DockerNetworkName,
 
 			"SLUG":          wisski.Slug,
 			"VIRTUAL_HOST":  wisski.Domain(),
-			"HTTPS_ENABLED": wisski.instances.Config.HTTPSEnabledEnv(),
+			"HTTPS_ENABLED": wisski.Core.Config.HTTPSEnabledEnv(),
 		},
 	}
 }
+
+// Shell executes a shell command inside the instance.
+func (wisski *WissKI) Shell(io stream.IOStream, argv ...string) (int, error) {
+	return wisski.Barrel().Exec(io, "barrel", "/bin/sh", append([]string{"/user_shell.sh"}, argv...)...)
+}

internal/wisski/update.go

@@ -1,8 +1,9 @@
-package instances
+package wisski
 
 import (
 	"time"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/component/meta"
 	"github.com/FAU-CDI/wisski-distillery/pkg/environment"
 	"github.com/tkw1536/goprogram/exit"
 	"github.com/tkw1536/goprogram/stream"
@@ -26,14 +27,11 @@ func (wisski *WissKI) BlindUpdate(io stream.IOStream) error {
 	return wisski.setLastUpdate()
 }
 
-const KeyLastUpdate MetaKey = "lastUpdate"
+var lastUpdate = meta.StorageFor[int64]("lastUpdate")
 
 func (wisski *WissKI) LastUpdate() (t time.Time, err error) {
-	var epoch int64
-
-	// read the epoch!
-	err = wisski.Metadata().Get(KeyLastUpdate, &epoch)
-	if err == ErrMetadatumNotSet {
+	epoch, err := lastUpdate(wisski.storage()).Get()
+	if err == meta.ErrMetadatumNotSet {
 		return t, nil
 	}
 	if err != nil {
@@ -45,5 +43,5 @@ func (wisski *WissKI) LastUpdate() (t time.Time, err error) {
 }
 
 func (wisski *WissKI) setLastUpdate() error {
-	return wisski.Metadata().Set(KeyLastUpdate, time.Now().Unix())
+	return lastUpdate(wisski.storage()).Set(time.Now().Unix())
 }

internal/wisski/wisski.go

@@ -0,0 +1,60 @@
+// Package wisski provides WissKI
+package wisski
+
+import (
+	"github.com/FAU-CDI/wisski-distillery/internal/component"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/meta"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/snapshotslog"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/sql"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/triplestore"
+	"github.com/FAU-CDI/wisski-distillery/internal/models"
+)
+
+// WissKI represents a single WissKI Instance
+type WissKI struct {
+	models.Instance // whatever is stored inside the underlying instance
+
+	// Drupal credentials - not stored in the database
+	DrupalUsername string
+	DrupalPassword string
+
+	// references to components!
+	Core component.Core
+	Meta *meta.Meta
+	TS   *triplestore.Triplestore
+	SQL  *sql.SQL
+
+	SnapshotsLog *snapshotslog.SnapshotsLog
+}
+
+// Save saves this instance in the bookkeeping table
+func (wisski *WissKI) Save() error {
+	db, err := wisski.SQL.QueryTable(false, models.InstanceTable)
+	if err != nil {
+		return err
+	}
+
+	// it has never been created => we need to create it in the database
+	if wisski.Instance.Created.IsZero() {
+		return db.Create(&wisski.Instance).Error
+	}
+
+	// Update based on the primary key!
+	return db.Where("pk = ?", wisski.Instance.Pk).Updates(&wisski.Instance).Error
+}
+
+// Delete deletes this instance from the bookkeeping table
+func (wisski *WissKI) Delete() error {
+	db, err := wisski.SQL.QueryTable(false, models.InstanceTable)
+	if err != nil {
+		return err
+	}
+
+	// doesn't exist => nothing to delete
+	if wisski.Instance.Created.IsZero() {
+		return nil
+	}
+
+	// delete it directly
+	return db.Delete(&wisski.Instance).Error
+}