feat(03-01): add shared postgres pool and plugin migrations

Open one pgx stdlib *sql.DB, hand it to GORM, and run per-plugin
gormigrate sets with isolated history tables after an ICU pl-PL check.

Co-authored-by: Cursor <cursoragent@cursor.com>

lagoon/migrations.go

@@ -0,0 +1,155 @@
+package lagoon
+
+import (
+	"fmt"
+	"strings"
+	"unicode"
+
+	"git.golem15.com/golem15/summercms/pact"
+	"git.golem15.com/golem15/summercms/party"
+	"github.com/go-gormigrate/gormigrate/v2"
+	"gorm.io/gorm"
+)
+
+const historyTablePrefix = "summer_migrations_"
+
+// HistoryTableName returns the isolated gormigrate table for pluginID.
+func HistoryTableName(pluginID string) (string, error) {
+	if err := validatePluginID(pluginID); err != nil {
+		return "", err
+	}
+	return historyTablePrefix + strings.ReplaceAll(pluginID, ".", "_"), nil
+}
+
+func validatePluginID(id string) error {
+	if id == "" {
+		return fmt.Errorf("lagoon: plugin id is empty")
+	}
+	for _, r := range id {
+		if r == '.' || unicode.IsLower(r) || unicode.IsDigit(r) {
+			continue
+		}
+		return fmt.Errorf("lagoon: plugin id %q is not a valid history table name", id)
+	}
+	if strings.Contains(id, "..") || strings.HasPrefix(id, ".") || strings.HasSuffix(id, ".") {
+		return fmt.Errorf("lagoon: plugin id %q is not a valid history table name", id)
+	}
+	return nil
+}
+
+func migrator(gdb *gorm.DB, pluginID string, migrations []*gormigrate.Migration) (*gormigrate.Gormigrate, error) {
+	table, err := HistoryTableName(pluginID)
+	if err != nil {
+		return nil, err
+	}
+	return gormigrate.New(gdb, &gormigrate.Options{
+		TableName:      table,
+		UseTransaction: true,
+	}, migrations), nil
+}
+
+// Migrate runs each plugin's HasMigrations set in party.Activate order.
+func Migrate(gdb *gorm.DB, plugins []party.Plugin) error {
+	if gdb == nil {
+		return fmt.Errorf("lagoon: gorm db is nil")
+	}
+	for _, p := range plugins {
+		hm, ok := p.(pact.HasMigrations)
+		if !ok {
+			continue
+		}
+		migrations := hm.Migrations()
+		if len(migrations) == 0 {
+			continue
+		}
+		m, err := migrator(gdb, p.ID(), migrations)
+		if err != nil {
+			return err
+		}
+		if err := m.Migrate(); err != nil {
+			return fmt.Errorf("lagoon: migrate %s: %w", p.ID(), err)
+		}
+	}
+	return nil
+}
+
+// RollbackLast rolls back the last migration of pluginID.
+func RollbackLast(gdb *gorm.DB, plugins []party.Plugin, pluginID string) error {
+	if gdb == nil {
+		return fmt.Errorf("lagoon: gorm db is nil")
+	}
+	pluginID = strings.TrimSpace(pluginID)
+	if pluginID == "" {
+		pluginID = lastMigrationPlugin(plugins)
+	}
+	if pluginID == "" {
+		return fmt.Errorf("lagoon: no plugin migrations to roll back")
+	}
+	for _, p := range plugins {
+		if p.ID() != pluginID {
+			continue
+		}
+		hm, ok := p.(pact.HasMigrations)
+		if !ok {
+			return fmt.Errorf("lagoon: plugin %q has no migrations", pluginID)
+		}
+		m, err := migrator(gdb, p.ID(), hm.Migrations())
+		if err != nil {
+			return err
+		}
+		if err := m.RollbackLast(); err != nil {
+			return fmt.Errorf("lagoon: rollback %s: %w", pluginID, err)
+		}
+		return nil
+	}
+	return fmt.Errorf("lagoon: plugin %q is not activated", pluginID)
+}
+
+func lastMigrationPlugin(plugins []party.Plugin) string {
+	for i := len(plugins) - 1; i >= 0; i-- {
+		p := plugins[i]
+		hm, ok := p.(pact.HasMigrations)
+		if !ok || len(hm.Migrations()) == 0 {
+			continue
+		}
+		return p.ID()
+	}
+	return ""
+}
+
+// StatusRow is one plugin's recorded migration ids.
+type StatusRow struct {
+	Plugin string
+	Table  string
+	IDs    []string
+}
+
+// Status reads each plugin history table.
+func Status(gdb *gorm.DB, plugins []party.Plugin) ([]StatusRow, error) {
+	if gdb == nil {
+		return nil, fmt.Errorf("lagoon: gorm db is nil")
+	}
+	var rows []StatusRow
+	for _, p := range plugins {
+		if _, ok := p.(pact.HasMigrations); !ok {
+			continue
+		}
+		table, err := HistoryTableName(p.ID())
+		if err != nil {
+			return nil, err
+		}
+		row := StatusRow{Plugin: p.ID(), Table: table}
+		if !gdb.Migrator().HasTable(table) {
+			rows = append(rows, row)
+			continue
+		}
+		if err := gdb.Table(table).Order("id").Pluck("id", &row.IDs).Error; err != nil {
+			return nil, fmt.Errorf("lagoon: status %s: %w", p.ID(), err)
+		}
+		if row.IDs == nil {
+			row.IDs = []string{}
+		}
+		rows = append(rows, row)
+	}
+	return rows, nil
+}