Add a metadata system

internal/component/sql/connect.go

@@ -21,8 +21,8 @@ import (
 // ========== low-level connection ==========
 //
 
-// Query performs a database query, outside a database contect
-func (sql *SQL) Query(query string, args ...interface{}) error {
+// Exec executes a database-independent database query.
+func (sql *SQL) Exec(query string, args ...interface{}) error {
 	// connect to the server
 	conn, err := sql.connect("")
 	if err != nil {
@@ -39,10 +39,10 @@ func (sql *SQL) Query(query string, args ...interface{}) error {
 	}
 }
 
-// WaitQuery waits for the query interface to be able to connect to the database
-func (sql *SQL) WaitQuery() error {
+// WaitExec waits for the query interface to be able to connect to the database
+func (sql *SQL) WaitExec() error {
 	return wait.Wait(func() bool {
-		err := sql.Query("select 1;")
+		err := sql.Exec("select 1;")
 		// log.Printf("[WaitQuery] %s\n", err) // debug
 		return err == nil
 	}, sql.PollInterval, sql.PollContext)
@@ -52,8 +52,8 @@ func (sql *SQL) WaitQuery() error {
 // ========== connection via gorm ==========
 //
 
-// QueryTable returns a gorm.DB to connect to the provided gorm database table
-func (sql *SQL) QueryTable(silent bool, name string) (*gorm.DB, error) {
+// QueryTable returns a gorm.DB to connect to the provided distillery database table
+func (sql *SQL) QueryTable(silent bool, table string) (*gorm.DB, error) {
 	conn, err := sql.connect(sql.Config.DistilleryDatabase)
 	if err != nil {
 		return nil, err
@@ -79,7 +79,7 @@ func (sql *SQL) QueryTable(silent bool, name string) (*gorm.DB, error) {
 	}
 
 	// set the table
-	db = db.Table(name)
+	db = db.Table(table)
 
 	// check that nothing went wrong
 	if db.Error != nil {

internal/component/sql/connect_shell.go

@@ -1 +0,0 @@
-package sql

internal/component/sql/provision.go

@@ -9,7 +9,10 @@ import (
 var errProvisionInvalidDatabaseParams = errors.New("Provision: Invalid parameters")
 var errProvisionInvalidGrant = errors.New("Provision: Grant failed")
 
-// Provision provisions a new sql database and user
+// Provision creates a new database with the given name.
+// It then generates a new user, with the name 'user' and the password 'password', that is then granted access to this database.
+//
+// Provision internally waits for the database to become available.
 func (sql *SQL) Provision(name, user, password string) error {
 
 	// NOTE(twiesing): We shouldn't use string concat to build sql queries.
@@ -41,6 +44,10 @@ func (sql *SQL) Provision(name, user, password string) error {
 
 var errCreateSuperuserGrant = errors.New("CreateSuperUser: Grant failed")
 
+// CreateSuperuser createsa new user, with the name 'user' and the password 'password'.
+// It then grants this user superuser status in the database.
+//
+// CreateSuperuser internally waits for the database to become available.
 func (sql *SQL) CreateSuperuser(user, password string, allowExisting bool) error {
 	// NOTE(twiesing): This function unsafely uses the shell directly to create a superuser.
 	// This is for two reasons:
@@ -70,9 +77,21 @@ func (sql *SQL) CreateSuperuser(user, password string, allowExisting bool) error
 	return nil
 }
 
+var errPurgeUser = errors.New("PurgeUser: Failed to drop user")
+
 // SQLPurgeUser deletes the specified user from the database
 func (sql *SQL) PurgeUser(user string) error {
-	return sql.Query("DROP USER IF EXISTS ?@`%`; FLUSH PRIVILEGES; ", user)
+	if !sqle.IsSafeDatabaseSingleQuote(user) {
+		return errPurgeUser
+	}
+
+	query := "DROP USER IF EXISTS '" + user + "'@'%';" +
+		"FLUSH PRIVILEGES;"
+	if !sql.unsafeQueryShell(query) {
+		return errPurgeUser
+	}
+
+	return nil
 }
 
 var errSQLPurgeDB = errors.New("unable to drop database: unsafe database name")
@@ -82,5 +101,5 @@ func (sql *SQL) PurgeDatabase(db string) error {
 	if !sqle.IsSafeDatabaseLiteral(db) {
 		return errSQLPurgeDB
 	}
-	return sql.Query("DROP DATABASE IF EXISTS `" + db + "`")
+	return sql.Exec("DROP DATABASE IF EXISTS `" + db + "`")
 }

internal/component/sql/update.go

@@ -8,6 +8,7 @@ import (
 	"github.com/FAU-CDI/wisski-distillery/pkg/logging"
 	"github.com/FAU-CDI/wisski-distillery/pkg/sqle"
 	"github.com/FAU-CDI/wisski-distillery/pkg/wait"
+	"github.com/tkw1536/goprogram/exit"
 	"github.com/tkw1536/goprogram/stream"
 )
 
@@ -36,6 +37,10 @@ func (sql *SQL) unsafeQueryShell(query string) bool {
 
 var errSQLUnableToCreateUser = errors.New("unable to create administrative user")
 var errSQLUnsafeDatabaseName = errors.New("distillery database has an unsafe name")
+var errSQLUnableToMigrate = exit.Error{
+	Message:  "unable to migrate %s table: %s",
+	ExitCode: exit.ExitGeneric,
+}
 
 // Update initializes or updates the SQL database.
 func (sql *SQL) Update(io stream.IOStream) error {
@@ -62,7 +67,7 @@ func (sql *SQL) Update(io stream.IOStream) error {
 			return errSQLUnsafeDatabaseName
 		}
 		createDBSQL := fmt.Sprintf("CREATE DATABASE IF NOT EXISTS `%s`;", sql.Config.DistilleryDatabase)
-		if err := sql.Query(createDBSQL); err != nil {
+		if err := sql.Exec(createDBSQL); err != nil {
 			return err
 		}
 	}
@@ -71,18 +76,36 @@ func (sql *SQL) Update(io stream.IOStream) error {
 	logging.LogMessage(io, "Waiting for database update to be complete")
 	sql.WaitQueryTable()
 
-	// open the database
-	logging.LogMessage(io, "Migrating instances table")
-	{
-		db, err := sql.QueryTable(false, models.InstanceTable)
-		if err != nil {
-			return fmt.Errorf("unable to access bookkeeping table: %s", err)
-		}
-
-		if err := db.AutoMigrate(&models.Instance{}); err != nil {
-			return fmt.Errorf("unable to migrate bookkeeping table: %s", err)
-		}
+	tables := []struct {
+		name  string
+		model any
+		table string
+	}{
+		{
+			"instance",
+			&models.Instance{},
+			models.InstanceTable,
+		},
+		{
+			"metadata",
+			&models.Metadatum{},
+			models.MetadataTable,
+		},
 	}
 
-	return nil
+	// migrate all of the tables!
+	return logging.LogOperation(func() error {
+		for _, table := range tables {
+			logging.LogMessage(io, "migrating %q table", table.name)
+			db, err := sql.QueryTable(false, table.table)
+			if err != nil {
+				return errSQLUnableToMigrate.WithMessageF(table.name, "unable to access table")
+			}
+
+			if err := db.AutoMigrate(table.model); err != nil {
+				return errSQLUnableToMigrate.WithMessageF(table.name, err)
+			}
+		}
+		return nil
+	}, io, "migrating database tables")
 }