Do a large chunk of the move to go

This commit moves a huge chunk of the code to go. The TODO.md document
indicates what is left to be done.

env/stack_sql.go

@@ -0,0 +1,221 @@
+package env
+
+import (
+	"fmt"
+	"io/fs"
+	"time"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/bookkeeping"
+	"github.com/FAU-CDI/wisski-distillery/internal/logging"
+	"github.com/FAU-CDI/wisski-distillery/internal/sqle"
+	"github.com/FAU-CDI/wisski-distillery/internal/stack"
+	"github.com/FAU-CDI/wisski-distillery/internal/wait"
+	"github.com/pkg/errors"
+	"github.com/tkw1536/goprogram/exit"
+	"github.com/tkw1536/goprogram/stream"
+	"gorm.io/driver/mysql"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+// SQLStack returns the docker stack that handles the sql database.
+func (dis *Distillery) SQLStack() stack.Installable {
+	return dis.asCoreStack(stack.Installable{
+		Stack: stack.Stack{
+			Name: "sql",
+		},
+
+		MakeDirsPerm: fs.ModeDir | fs.ModePerm,
+		MakeDirs: []string{
+			"data",
+		},
+	})
+}
+
+// SQLStackPath returns the path the SQLStack() lives at.
+func (dis *Distillery) SQLStackPath() string {
+	return dis.SQLStack().Dir
+}
+
+// sqlOpen opens a new sql connection to the provided database using the administrative credentials
+func (env Distillery) sqlOpen(database string, config *gorm.Config) (*gorm.DB, error) {
+	sql := mysql.Config{
+		DSN:               fmt.Sprintf("%s:%s@tcp(%s)/%s?charset=utf8&parseTime=True&loc=Local", env.Config.MysqlAdminUser, env.Config.MysqlAdminPassword, "127.0.0.1:3306", database),
+		DefaultStringSize: 256,
+	}
+
+	db, err := gorm.Open(mysql.New(sql), config)
+	if err != nil {
+		return db, err
+	}
+
+	gdb, err := db.DB()
+	if err != nil {
+		return db, err
+	}
+	gdb.SetMaxIdleConns(0)
+
+	return db, nil
+}
+
+var errSQL = exit.Error{
+	Message:  "error querying sql database: %s",
+	ExitCode: exit.ExitGeneric,
+}
+
+// sqlBkTable returns a gorm connection to the bookkeeping database.
+func (dis *Distillery) sqlBkTable(silent bool) (*gorm.DB, error) {
+
+	config := &gorm.Config{}
+	if silent {
+		config.Logger = logger.Default.LogMode(logger.Silent)
+	}
+
+	// open the database
+	db, err := dis.sqlOpen(dis.Config.DistilleryBookkeepingDatabase, config)
+	if err != nil {
+		return nil, errSQL.WithMessageF(err)
+	}
+
+	// load the table
+	table := db.Table(dis.Config.DistilleryBookkeepingTable)
+	if table.Error != nil {
+		return nil, errSQL.WithMessageF(err)
+	}
+
+	return table, nil
+}
+
+// SQLShell executes a mysql shell inside the SQLStack.
+func (dis *Distillery) SQLShell(io stream.IOStream, argv ...string) int {
+	return dis.SQLStack().Exec(io, "sql", "mysql", argv...)
+}
+
+var errSQLBootstrap = exit.Error{
+	Message:  "Unable to boostrap SQL: %s",
+	ExitCode: exit.ExitGeneric,
+}
+
+const waitSQLInterval = 1 * time.Second
+
+// SQLWaitForShell waits for the sql database to be reachable via a docker-compose shell
+func (dis *Distillery) SQLWaitForShell() error {
+	n := stream.FromNil()
+	return wait.Wait(func() bool {
+		return dis.SQLShell(n, "-e", "show databases;") == 0
+	}, waitSQLInterval, dis.Context())
+}
+
+// SQLWaitForConnection waits for the sql connection to be alive
+func (dis *Distillery) SQLWaitForConnection() error {
+	return wait.Wait(func() bool {
+		_, err := dis.sqlBkTable(true)
+		return err == nil
+	}, waitSQLInterval, dis.Context())
+}
+
+var errInvalidDatabaseName = errors.New("SQLProvision: Invalid database name")
+
+func (dis *Distillery) sqlRaw(query string, args ...interface{}) bool {
+	sql := sqle.Format(query, args...)
+	return dis.SQLShell(stream.FromNil(), "-e", sql) == 0
+}
+
+// SQLProvision provisions a new sql database and user
+func (dis *Distillery) SQLProvision(name, user, password string) error {
+	// wait for the database
+	if err := dis.SQLWaitForShell(); err != nil {
+		return err
+	}
+
+	// it's not a safe database name!
+	if !sqle.IsSafeDatabaseName(name) {
+		return errInvalidDatabaseName
+	}
+
+	// create the database and user!
+	if !dis.sqlRaw("CREATE DATABASE `"+name+"`; CREATE USER ?@`%` IDENTIFIED BY ?; GRANT ALL PRIVILEGES ON `"+name+"`.* TO ?@`%`; FLUSH PRIVILEGES;", user, password, user) {
+		return errors.New("SQLProvision: Failed to create user")
+	}
+
+	// and done!
+	return nil
+}
+
+var errSQLPurgeUser = exit.Error{
+	Message:  "Unable to delete user",
+	ExitCode: exit.ExitGeneric,
+}
+
+// SQLPurgeUser deletes the specified user from the database
+func (dis *Distillery) SQLPurgeUser(user string) error {
+	if !dis.sqlRaw("DROP USER IF EXISTS ?@`%`; FLUSH PRIVILEGES; ", user) {
+		return errSQLPurgeUser
+	}
+
+	return nil
+}
+
+var errSQLPurgeDB = exit.Error{
+	Message:  "Unable to delete database",
+	ExitCode: exit.ExitGeneric,
+}
+
+// SQLPurgeDatabase deletes the specified db from the database
+func (dis *Distillery) SQLPurgeDatabase(db string) error {
+	if !sqle.IsSafeDatabaseName(db) {
+		return errSQLPurgeDB
+	}
+	if !dis.sqlRaw("DROP DATABASE IF EXISTS `" + db + "`") {
+		return errSQLPurgeDB
+	}
+	return nil
+}
+
+// SQLBootstrap bootstraps the SQL database, and makes sure that the bookkeeping table is up-to-date
+func (dis *Distillery) SQLBootstrap(io stream.IOStream) error {
+	if err := dis.SQLWaitForShell(); err != nil {
+		return errSQLBootstrap.WithMessageF(err)
+	}
+
+	// create the admin user
+	logging.LogMessage(io, "Creating administrative user")
+	{
+		username := dis.Config.MysqlAdminUser
+		password := dis.Config.MysqlAdminPassword
+		if !dis.sqlRaw("CREATE USER IF NOT EXISTS ?@'%' IDENTIFIED BY ?; GRANT ALL PRIVILEGES ON *.* TO ?@`%` WITH GRANT OPTION; FLUSH PRIVILEGES;", username, password, username) {
+			return errSQLBootstrap.WithMessageF("Unable to create administrative user")
+		}
+	}
+
+	// create the admin user
+	logging.LogMessage(io, "Creating sql database")
+	{
+		if !sqle.IsSafeDatabaseName(dis.Config.DistilleryBookkeepingDatabase) {
+			return errSQLBootstrap.WithMessageF("Unsafe database name")
+		}
+		createDBSQL := fmt.Sprintf("CREATE DATABASE IF NOT EXISTS `%s`;", dis.Config.DistilleryBookkeepingDatabase)
+		if !dis.sqlRaw(createDBSQL) {
+			return errSQLBootstrap.WithMessageF(createDBSQL)
+		}
+	}
+
+	// wait for the database to come up
+	logging.LogMessage(io, "Waiting for database update to be complete")
+	dis.SQLWaitForConnection()
+
+	// open the database
+	logging.LogMessage(io, "Migrating bookkeeping table")
+	{
+		db, err := dis.sqlBkTable(false)
+		if err != nil {
+			return errSQLBootstrap.WithMessageF(err)
+		}
+
+		if err := db.AutoMigrate(&bookkeeping.Instance{}); err != nil {
+			return errSQLBootstrap.WithMessageF(err)
+		}
+	}
+
+	return nil
+}