Json database refactoring

database/database.go

@@ -1,15 +1,7 @@
 package database
 
 import (
-	"encoding/json"
-	"fmt"
 	"io"
-	"log"
-	"os"
-
-	"git.phc.dm.unipi.it/phc/storage/store"
-	"git.phc.dm.unipi.it/phc/storage/utils"
-	"golang.org/x/exp/slices"
 )
 
 type MonitorWidget struct {
@@ -53,391 +45,3 @@ type Database interface {
 	SetBucketObject(bucket, id string, r io.Reader) error
 	DeleteBucketObject(bucket, id string) error
 }
-
-type JsonBucketSettings struct {
-	Path string `json:"path"`
-}
-
-type jsonBucket struct {
-	Name    string   `json:"name"`
-	Objects []string `json:"objects"`
-
-	Settings *JsonBucketSettings `json:"settings"`
-}
-
-type jsonDB struct {
-	file string
-
-	PrefixSize int `json:"prefixSize"`
-
-	DashboardState DashboardState         `json:"dashboardState"`
-	Buckets        map[string]*jsonBucket `json:"buckets"`
-
-	APIKeys []string `json:"api-keys"`
-}
-
-func NewJSON(file string) Database {
-	db := &jsonDB{
-		file:       file,
-		PrefixSize: 2,
-		DashboardState: DashboardState{
-			Widgets: []MonitorWidget{},
-		},
-		Buckets: map[string]*jsonBucket{},
-		APIKeys: []string{},
-	}
-
-	err := db.load()
-	if err != nil {
-		panic(err)
-	}
-
-	return db
-}
-
-// func writeTransaction[T any](db *jsonDB, transactionFunc func(db *jsonDB) (T, error)) (T, error) {
-// 	var zero T
-// 	if err := db.load(); err != nil {
-// 		return zero, err
-// 	}
-// 	v, err := transactionFunc(db)
-// 	if err := db.store(); err != nil {
-// 		return zero, err
-// 	}
-// 	return v, err
-// }
-
-func (db *jsonDB) setup() error {
-	if _, err := os.Stat(db.file); !os.IsNotExist(err) {
-		return nil
-	}
-
-	log.Printf("missing %q, creating empty database file", db.file)
-
-	f, err := os.Create(db.file)
-	defer f.Close()
-	if err != nil {
-		return err
-	}
-
-	enc := json.NewEncoder(f)
-	enc.SetIndent("", "    ")
-	if err := enc.Encode(&db); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (db *jsonDB) store() error {
-	f, err := os.Create(db.file)
-	defer f.Close()
-	if err != nil {
-		return err
-	}
-
-	enc := json.NewEncoder(f)
-	enc.SetIndent("", "  ")
-	if err := enc.Encode(&db); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (db *jsonDB) load() error {
-	if err := db.setup(); err != nil {
-		return err
-	}
-
-	f, err := os.Open(db.file)
-	defer f.Close()
-	if err != nil {
-		return err
-	}
-
-	if err := json.NewDecoder(f).Decode(&db); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (db *jsonDB) GetDashboardState() (DashboardState, error) {
-	if err := db.load(); err != nil {
-		return DashboardState{}, err
-	}
-
-	return db.DashboardState, nil
-}
-
-func (db *jsonDB) SetDashboardState(state DashboardState) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	db.DashboardState = state
-
-	if err := db.store(); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (db *jsonDB) CreateAPIKey() (string, error) {
-	if err := db.load(); err != nil {
-		return "", err
-	}
-
-	key := utils.GenerateRandomString(32)
-	db.APIKeys = append(db.APIKeys, key)
-
-	if err := db.store(); err != nil {
-		return "", err
-	}
-
-	return key, nil
-}
-
-func (db *jsonDB) AllAPIKeys() ([]string, error) {
-	if err := db.load(); err != nil {
-		return nil, err
-	}
-
-	return db.APIKeys, nil
-}
-
-func (db *jsonDB) CheckAPIKey(key string) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	if !slices.Contains(db.APIKeys, key) {
-		return fmt.Errorf("the given api key %q is invalid", key)
-	}
-
-	return nil
-}
-
-func (db *jsonDB) RemoveAPIKey(key string) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	i := slices.Index(db.APIKeys, key)
-	if i == -1 {
-		return fmt.Errorf("the given api key %q is invalid", key)
-	}
-
-	db.APIKeys = append(db.APIKeys[:i], db.APIKeys[i+1:]...)
-
-	if err := db.store(); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-//
-// Bucket Methods
-//
-
-func (db *jsonDB) CreateBucket(bucket string, settings any) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	if _, found := db.Buckets[bucket]; found {
-		return fmt.Errorf("bucket named %q already present", bucket)
-	}
-
-	bi := &jsonBucket{
-		Name: bucket,
-		Settings: &JsonBucketSettings{
-			Path: bucket + "/",
-		},
-		Objects: []string{},
-	}
-
-	if settings != nil {
-		bi.Settings = settings.(*JsonBucketSettings)
-	}
-
-	db.Buckets[bucket] = bi
-
-	if err := db.store(); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (db *jsonDB) GetBucketSettings(bucket string) (any, error) {
-	if err := db.load(); err != nil {
-		return nil, err
-	}
-
-	if _, found := db.Buckets[bucket]; !found {
-		return nil, fmt.Errorf("bucket named %q not found", bucket)
-	}
-
-	return db.Buckets[bucket].Settings, nil
-}
-
-func (db *jsonDB) SetBucketSettings(bucket string, settings any) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	b, found := db.Buckets[bucket]
-	if !found {
-		return fmt.Errorf("bucket named %q not found", bucket)
-	}
-
-	b.Settings = settings.(*JsonBucketSettings)
-
-	log.Printf("[Warning] Bucket %q settings changed but bucket migration is not yet implemented (move the folder yourself)", bucket)
-
-	if err := db.store(); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (db *jsonDB) DeleteBucket(bucket string) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	if _, found := db.Buckets[bucket]; !found {
-		return fmt.Errorf("bucket named %q not found", bucket)
-	}
-
-	delete(db.Buckets, bucket)
-
-	log.Printf("The bucket named %q was removed but its files are still on disk", bucket)
-
-	if err := db.store(); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (db *jsonDB) AllBuckets() ([]string, error) {
-	if err := db.load(); err != nil {
-		return nil, err
-	}
-
-	buckets := make([]string, 0, len(db.Buckets))
-
-	for _, b := range db.Buckets {
-		buckets = append(buckets, b.Name)
-	}
-
-	return buckets, nil
-}
-
-func (db *jsonDB) CreateBucketObject(bucket string, r io.Reader) (string, error) {
-	if err := db.load(); err != nil {
-		return "", err
-	}
-
-	b, found := db.Buckets[bucket]
-	if !found {
-		return "", fmt.Errorf("bucket named %q not found", bucket)
-	}
-
-	id, err := store.Create(b.Settings.Path, db.PrefixSize, r)
-	if err != nil {
-		return "", err
-	}
-
-	b.Objects = append(b.Objects, id)
-
-	if err := db.store(); err != nil {
-		return "", err
-	}
-
-	return id, err
-}
-
-func (db *jsonDB) SetBucketObject(bucket, id string, r io.Reader) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	b, found := db.Buckets[bucket]
-	if !found {
-		return fmt.Errorf("bucket named %q not found", bucket)
-	}
-
-	if err := db.store(); err != nil {
-		return err
-	}
-
-	return store.Update(b.Settings.Path, db.PrefixSize, id, r)
-}
-
-func (db *jsonDB) GetBucketObject(bucket, id string, w io.Writer) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	b, found := db.Buckets[bucket]
-	if !found {
-		return fmt.Errorf("bucket named %q not found", bucket)
-	}
-
-	return store.Read(b.Settings.Path, db.PrefixSize, id, w)
-}
-
-func (db *jsonDB) DeleteBucketObject(bucket, id string) error {
-	if err := db.load(); err != nil {
-		return err
-	}
-
-	b, found := db.Buckets[bucket]
-	if !found {
-		return fmt.Errorf("bucket named %q not found", bucket)
-	}
-
-	if err := store.Delete(b.Settings.Path, db.PrefixSize, id); err != nil {
-		return err
-	}
-
-	i := slices.Index(b.Objects, id)
-	b.Objects = append(b.Objects[:i], b.Objects[i+1:]...)
-
-	if err := db.store(); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (db *jsonDB) AllBucketObjects(bucket string) ([]string, error) {
-	if err := db.load(); err != nil {
-		return nil, err
-	}
-
-	b, found := db.Buckets[bucket]
-	if !found {
-		return nil, fmt.Errorf("bucket named %q not found", bucket)
-	}
-
-	objects, err := store.All(b.Settings.Path)
-	if err != nil {
-		return nil, err
-	}
-
-	b.Objects = objects
-
-	if err := db.store(); err != nil {
-		return nil, err
-	}
-
-	return b.Objects, nil
-}

database/jsondb.go

@@ -0,0 +1,379 @@
+package database
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"sync"
+
+	"git.phc.dm.unipi.it/phc/storage/store"
+	"git.phc.dm.unipi.it/phc/storage/utils"
+	"golang.org/x/exp/slices"
+)
+
+type JsonBucketSettings struct {
+	Path string `json:"path"`
+}
+
+type jsonBucket struct {
+	Name    string   `json:"name"`
+	Objects []string `json:"objects"`
+
+	Settings *JsonBucketSettings `json:"settings"`
+}
+
+type jsonDB struct {
+	mu sync.Mutex
+
+	file string
+
+	PrefixSize int `json:"prefixSize"`
+
+	DashboardState DashboardState         `json:"dashboardState"`
+	Buckets        map[string]*jsonBucket `json:"buckets"`
+
+	APIKeys []string `json:"api-keys"`
+}
+
+func NewJSON(file string) Database {
+	db := &jsonDB{
+		file:       file,
+		PrefixSize: 2,
+		DashboardState: DashboardState{
+			Widgets: []MonitorWidget{},
+		},
+		Buckets: map[string]*jsonBucket{},
+		APIKeys: []string{},
+	}
+
+	err := db.load()
+	if err != nil {
+		panic(err)
+	}
+
+	return db
+}
+
+func (db *jsonDB) setup() error {
+	if _, err := os.Stat(db.file); !os.IsNotExist(err) {
+		return nil
+	}
+
+	log.Printf("missing %q, creating empty database file", db.file)
+
+	f, err := os.Create(db.file)
+	defer f.Close()
+	if err != nil {
+		return err
+	}
+
+	enc := json.NewEncoder(f)
+	enc.SetIndent("", "    ")
+	if err := enc.Encode(&db); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (db *jsonDB) store() error {
+	f, err := os.Create(db.file)
+	defer f.Close()
+	if err != nil {
+		return err
+	}
+
+	enc := json.NewEncoder(f)
+	enc.SetIndent("", "  ")
+	if err := enc.Encode(&db); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (db *jsonDB) load() error {
+	if err := db.setup(); err != nil {
+		return err
+	}
+
+	f, err := os.Open(db.file)
+	defer f.Close()
+	if err != nil {
+		return err
+	}
+
+	if err := json.NewDecoder(f).Decode(&db); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func withValue[T any](
+	transactorFunc func(func() error) error,
+	workFunc func() (T, error)) (T, error) {
+
+	var value T
+
+	if err := transactorFunc(func() error {
+		var err error
+		value, err = workFunc()
+
+		return err
+	}); err != nil {
+		var zero T
+		return zero, err
+	}
+
+	return value, nil
+}
+
+func (db *jsonDB) writeTransaction(workFunc func() error) error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	if err := db.load(); err != nil {
+		return err
+	}
+
+	if err := workFunc(); err != nil {
+		return err
+	}
+
+	if err := db.store(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (db *jsonDB) readTransaction(transactionFunc func() error) error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	if err := db.load(); err != nil {
+		return err
+	}
+
+	if err := transactionFunc(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (db *jsonDB) GetDashboardState() (DashboardState, error) {
+	return withValue(db.readTransaction, func() (DashboardState, error) {
+		return db.DashboardState, nil
+	})
+}
+
+func (db *jsonDB) SetDashboardState(state DashboardState) error {
+	if err := db.load(); err != nil {
+		return err
+	}
+
+	db.DashboardState = state
+
+	if err := db.store(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (db *jsonDB) CreateAPIKey() (string, error) {
+	return withValue(db.writeTransaction, func() (string, error) {
+		key := utils.GenerateRandomString(32)
+		db.APIKeys = append(db.APIKeys, key)
+
+		return key, nil
+	})
+}
+
+func (db *jsonDB) AllAPIKeys() ([]string, error) {
+	return withValue(db.readTransaction, func() ([]string, error) {
+		return db.APIKeys, nil
+	})
+}
+
+func (db *jsonDB) CheckAPIKey(key string) error {
+	return db.readTransaction(func() error {
+		if !slices.Contains(db.APIKeys, key) {
+			return fmt.Errorf("the given api key %q is invalid", key)
+		}
+
+		return nil
+	})
+}
+
+func (db *jsonDB) RemoveAPIKey(key string) error {
+	return db.writeTransaction(func() error {
+		i := slices.Index(db.APIKeys, key)
+		if i == -1 {
+			return fmt.Errorf("the given api key %q is invalid", key)
+		}
+
+		db.APIKeys = append(db.APIKeys[:i], db.APIKeys[i+1:]...)
+
+		return nil
+	})
+}
+
+//
+// Bucket Methods
+//
+
+func (db *jsonDB) CreateBucket(bucket string, settings any) error {
+	return db.writeTransaction(func() error {
+		if _, found := db.Buckets[bucket]; found {
+			return fmt.Errorf("bucket named %q already present", bucket)
+		}
+
+		bi := &jsonBucket{
+			Name: bucket,
+			Settings: &JsonBucketSettings{
+				Path: bucket + "/",
+			},
+			Objects: []string{},
+		}
+
+		if settings != nil {
+			bi.Settings = settings.(*JsonBucketSettings)
+		}
+
+		db.Buckets[bucket] = bi
+
+		return nil
+	})
+}
+
+func (db *jsonDB) GetBucketSettings(bucket string) (any, error) {
+	return withValue(db.readTransaction, func() (any, error) {
+		if _, found := db.Buckets[bucket]; !found {
+			return nil, fmt.Errorf("bucket named %q not found", bucket)
+		}
+
+		return db.Buckets[bucket].Settings, nil
+	})
+}
+
+func (db *jsonDB) SetBucketSettings(bucket string, settings any) error {
+	return db.writeTransaction(func() error {
+		b, found := db.Buckets[bucket]
+		if !found {
+			return fmt.Errorf("bucket named %q not found", bucket)
+		}
+
+		b.Settings = settings.(*JsonBucketSettings)
+
+		log.Printf("[Warning] Bucket %q settings changed but bucket migration is not yet implemented (move the folder yourself)", bucket)
+
+		return nil
+	})
+}
+
+func (db *jsonDB) DeleteBucket(bucket string) error {
+	return db.writeTransaction(func() error {
+		if _, found := db.Buckets[bucket]; !found {
+			return fmt.Errorf("bucket named %q not found", bucket)
+		}
+
+		delete(db.Buckets, bucket)
+
+		log.Printf("The bucket named %q was removed but its files are still on disk", bucket)
+
+		return nil
+	})
+}
+
+func (db *jsonDB) AllBuckets() ([]string, error) {
+	return withValue(db.readTransaction, func() ([]string, error) {
+		buckets := make([]string, 0, len(db.Buckets))
+
+		for _, b := range db.Buckets {
+			buckets = append(buckets, b.Name)
+		}
+
+		return buckets, nil
+	})
+}
+
+func (db *jsonDB) CreateBucketObject(bucket string, r io.Reader) (string, error) {
+	return withValue(db.writeTransaction, func() (string, error) {
+		b, found := db.Buckets[bucket]
+		if !found {
+			return "", fmt.Errorf("bucket named %q not found", bucket)
+		}
+
+		id, err := store.Create(b.Settings.Path, db.PrefixSize, r)
+		if err != nil {
+			return "", err
+		}
+
+		b.Objects = append(b.Objects, id)
+
+		return id, err
+	})
+}
+
+func (db *jsonDB) SetBucketObject(bucket, id string, r io.Reader) error {
+	return db.writeTransaction(func() error {
+		b, found := db.Buckets[bucket]
+		if !found {
+			return fmt.Errorf("bucket named %q not found", bucket)
+		}
+
+		return store.Update(b.Settings.Path, db.PrefixSize, id, r)
+	})
+}
+
+func (db *jsonDB) GetBucketObject(bucket, id string, w io.Writer) error {
+	return db.readTransaction(func() error {
+		b, found := db.Buckets[bucket]
+		if !found {
+			return fmt.Errorf("bucket named %q not found", bucket)
+		}
+
+		return store.Read(b.Settings.Path, db.PrefixSize, id, w)
+	})
+}
+
+func (db *jsonDB) DeleteBucketObject(bucket, id string) error {
+	return db.writeTransaction(func() error {
+		b, found := db.Buckets[bucket]
+		if !found {
+			return fmt.Errorf("bucket named %q not found", bucket)
+		}
+
+		if err := store.Delete(b.Settings.Path, db.PrefixSize, id); err != nil {
+			return err
+		}
+
+		i := slices.Index(b.Objects, id)
+		b.Objects = append(b.Objects[:i], b.Objects[i+1:]...)
+
+		return nil
+	})
+}
+
+func (db *jsonDB) AllBucketObjects(bucket string) ([]string, error) {
+	return withValue(db.writeTransaction, func() ([]string, error) {
+		b, found := db.Buckets[bucket]
+		if !found {
+			return nil, fmt.Errorf("bucket named %q not found", bucket)
+		}
+
+		objects, err := store.All(b.Settings.Path)
+		if err != nil {
+			return nil, err
+		}
+
+		b.Objects = objects
+
+		return b.Objects, nil
+	})
+}