The very basic client app, not adapted for mobiles.

client/internal/services/core/database.go

@@ -0,0 +1,44 @@
+package core
+
+import (
+	"context"
+	"errors"
+	"io/fs"
+
+	"github.com/jmoiron/sqlx"
+)
+
+// ServiceNameDatabase is a name for database service.
+const ServiceNameDatabase = "core/database"
+
+var (
+	// ErrDatabase indicates that error appeared somewhere in database service.
+	ErrDatabase = errors.New("database service")
+	// ErrDatabaseIsInvalid indicates that database service implementation is invalid.
+	ErrDatabaseIsInvalid = errors.New("database service implementation is invalid")
+)
+
+// Database is an interface for database service.
+type Database interface {
+	// Exec is a proxy for ExecContext from sqlx.
+	Exec(ctx context.Context, query string, params ...interface{}) error
+	// Get is a proxy for GetContext from sqlx.
+	Get(ctx context.Context, target interface{}, query string, params ...interface{}) error
+	// NamedExec is a proxy for NamedExecContext from sqlx.
+	NamedExec(ctx context.Context, query string, param interface{}) error
+	// RegisterMigrations registers migrations for applying from other services. Migrations should reside
+	// in "migrations" directory in passed filesystem.
+	RegisterMigrations(moduleName string, fs fs.FS) error
+	// Select is a proxy for SelectContext from sqlx.
+	Select(ctx context.Context, target interface{}, query string, params ...interface{}) error
+	// Transaction is a wrapper for transactions processing which wraps sqlx's transactions.
+	Transaction(ctx context.Context) (DatabaseTransaction, error)
+}
+
+// DatabaseTransaction is an interface for database transactions controllers implementations.
+type DatabaseTransaction interface {
+	Apply(steps ...TransactionFunc) error
+}
+
+// TransactionFunc is a function that is used in transactions to mangle with data.
+type TransactionFunc func(*sqlx.Tx) error