refactor routes,

use json encoding for route body parameters,
implement modify user/group/pool operations,
simplify schema by using comon lib struct tags and RequireAll and AtLeastOne helper functions,
properly implement locadb as Backend interface

app/localdb/localdb.go

@@ -9,32 +9,38 @@ import (
 )
 
 type DB struct {
+	path string
 	data map[string]common.Pool
 }
 
-func LoadDB(localDBPath string) (DB, error) {
-	db := DB{}
+var db *DB
+
+func (db *DB) load(localDBPath string) error {
+	db.data = make(map[string]common.Pool)
+	db.path = localDBPath
 
 	root, err := os.OpenRoot(".")
 	if err != nil {
-		return db, err
+		return err
 	}
 	defer root.Close()
 
 	content, err := root.ReadFile(localDBPath)
 	if err != nil {
-		return db, err
+		return err
 	}
 
 	err = json.Unmarshal(content, &db.data)
 	if err != nil {
-		return db, err
+		return err
 	}
-	return db, nil
+	return nil
 }
 
-func SaveDB(localDBPath string, db DB) error {
-	json, err := json.Marshal(db.data)
+func (db *DB) save() error {
+	localDBPath := db.path
+	// write to file with pretty print for readability reasons
+	json, err := json.MarshalIndent(db.data, "", "\t")
 	if err != nil {
 		return err
 	}
@@ -42,10 +48,116 @@ func SaveDB(localDBPath string, db DB) error {
 	return err
 }
 
+func NewClientFromCredentials(config common.LocalDBConfig, username common.Username, password string) (common.Backend, int, error) {
+	if db != nil {
+		return *db, http.StatusOK, nil
+	} else {
+		// load localdb if this is the first time
+		db = &DB{}
+		err := db.load(config.Path)
+		if err != nil {
+			return *db, http.StatusInternalServerError, err
+		} else {
+			return *db, http.StatusOK, nil
+		}
+	}
+}
+
 func (localdb DB) GetPool(poolname string) (common.Pool, []string, int, error) {
 	pool, ok := localdb.data[poolname]
 	if !ok {
-		return pool, []string{}, http.StatusNotFound, fmt.Errorf("pool %s not in localdb", poolname)
+		return pool, []string{}, http.StatusNotFound, fmt.Errorf("localdb pool %s does not exist", poolname)
 	}
 	return pool, []string{}, http.StatusOK, nil
 }
+
+func (localdb DB) NewPool(poolname string, pool common.Pool) (int, error) {
+	_, ok := localdb.data[poolname]
+	if ok {
+		return http.StatusBadRequest, fmt.Errorf("localdb pool %s already exists", poolname)
+	}
+	localdb.data[poolname] = pool
+	err := localdb.save()
+	if err != nil {
+		return http.StatusInternalServerError, err
+	} else {
+		return http.StatusOK, nil
+	}
+}
+
+func (localdb DB) ModPool(poolname string, pool common.Pool) (int, error) {
+	_, ok := localdb.data[poolname]
+	if !ok {
+		return http.StatusBadRequest, fmt.Errorf("localdb pool %s does not exist", poolname)
+	}
+	old_pool := localdb.data[poolname]
+	MergeNonZero(&old_pool, &pool)
+	err := localdb.save()
+	if err != nil {
+		return http.StatusInternalServerError, err
+	} else {
+		return http.StatusOK, nil
+	}
+}
+
+func (localdb DB) DelPool(poolname string) (int, error) {
+	_, ok := localdb.data[poolname]
+	if !ok {
+		return http.StatusBadRequest, fmt.Errorf("localdb pool %s does not exist", poolname)
+	}
+	delete(localdb.data, poolname)
+	err := localdb.save()
+	if err != nil {
+		return http.StatusInternalServerError, err
+	} else {
+		return http.StatusOK, nil
+	}
+}
+
+func (localdb DB) NewGroup(groupname common.Groupname, group common.Group) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement groups")
+}
+
+func (localdb DB) ModGroup(groupname common.Groupname, group common.Group) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement groups")
+}
+
+func (localdb DB) GetGroup(groupname common.Groupname) (common.Group, []string, int, error) {
+	return common.Group{}, []string{}, http.StatusNotImplemented, fmt.Errorf("localdb does not implement groups")
+}
+
+func (localdb DB) DelGroup(groupname common.Groupname) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement groups")
+}
+
+func (localdb DB) AddGroupToPool(groupname common.Groupname, poolname string) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement groups")
+}
+
+func (localdb DB) DelGroupFromPool(groupname common.Groupname, poolname string) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement groups")
+}
+
+func (localdb DB) NewUser(username common.Username, user common.User) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement users")
+}
+
+func (localdb DB) ModUser(username common.Username, user common.User) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement users")
+}
+
+func (localdb DB) GetUser(username common.Username) (common.User, int, error) {
+	return common.User{}, http.StatusNotImplemented, fmt.Errorf("localdb does not implement users")
+}
+
+func (localdb DB) DelUser(username common.Username) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement users")
+}
+
+func (localdb DB) AddUserToGroup(username common.Username, groupname common.Groupname) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement users")
+}
+
+func (localdb DB) DelUserFromGroup(username common.Username, groupname common.Groupname) (int, error) {
+	return http.StatusNotImplemented, fmt.Errorf("localdb does not implement users")
+}