Deploy main eacf1e7 to prod

Replaces #559, which conflicted.

Model: opus-5-5

internal/db/migrations/migrations.go

@@ -0,0 +1,135 @@
+// Package migrations holds the schema of each kind of SQLite file
+// webhooker writes, as numbered SQL files embedded in the binary, and
+// applies it when a file is opened.
+//
+// Each kind of file has its own directory. In each, 000_migration.sql
+// creates only the schema_migrations table, and 001_schema.sql holds
+// the whole schema. Before 1.0 a schema change is an edit to
+// 001_schema.sql, never a new file.
+package migrations
+
+import (
+	"embed"
+	"fmt"
+	"io/fs"
+	"path"
+	"strconv"
+	"strings"
+
+	"gorm.io/gorm"
+)
+
+// The directories, one for each kind of database file.
+const (
+	// Main is the main database, webhooker.db.
+	Main = "main"
+
+	// Events is a webhook's event database, events-{uuid}.db.
+	Events = "events"
+
+	// Archive is a database target's archive file.
+	Archive = "archive"
+)
+
+//go:embed main/*.sql events/*.sql archive/*.sql
+var files embed.FS
+
+// Apply runs each SQL file in dir, which is Main, Events or Archive,
+// that the database has not had yet, in the order of the number its
+// name starts with, and records that number in schema_migrations.
+// 000_migration.sql creates that table and records itself, so it runs
+// first, and only when the table is missing.
+//
+// It all runs in one transaction, so a failure leaves the file as it
+// was.
+func Apply(db *gorm.DB, dir string) error {
+	return db.Transaction(func(tx *gorm.DB) error {
+		var tables int
+
+		// Row().Scan, not (*gorm.DB).Scan: see internal/gormlog.
+		err := tx.Raw(
+			"SELECT count(*) FROM sqlite_master "+
+				"WHERE type = 'table' AND name = ?",
+			"schema_migrations",
+		).Row().Scan(&tables)
+		if err != nil {
+			return fmt.Errorf("looking for schema_migrations: %w", err)
+		}
+
+		if tables == 0 {
+			err = run(tx, path.Join(dir, "000_migration.sql"))
+			if err != nil {
+				return err
+			}
+		}
+
+		// fs.Glob lists the files in name order, which is number order.
+		names, err := fs.Glob(files, path.Join(dir, "*.sql"))
+		if err != nil {
+			return fmt.Errorf("listing migrations: %w", err)
+		}
+
+		for _, name := range names {
+			err = applyOnce(tx, name)
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	})
+}
+
+// applyOnce runs the migration file name and records its number,
+// unless schema_migrations already has that number.
+func applyOnce(tx *gorm.DB, name string) error {
+	number, _, _ := strings.Cut(path.Base(name), "_")
+
+	version, err := strconv.Atoi(number)
+	if err != nil {
+		return fmt.Errorf("numbering migration %s: %w", name, err)
+	}
+
+	var applied int
+
+	err = tx.Raw(
+		"SELECT count(*) FROM schema_migrations WHERE version = ?",
+		version,
+	).Row().Scan(&applied)
+	if err != nil {
+		return fmt.Errorf("checking migration %s: %w", name, err)
+	}
+
+	if applied > 0 {
+		return nil
+	}
+
+	err = run(tx, name)
+	if err != nil {
+		return err
+	}
+
+	err = tx.Exec(
+		"INSERT INTO schema_migrations (version) VALUES (?)", version,
+	).Error
+	if err != nil {
+		return fmt.Errorf("recording migration %s: %w", name, err)
+	}
+
+	return nil
+}
+
+// run executes every statement in the migration file name.
+func run(tx *gorm.DB, name string) error {
+	script, err := files.ReadFile(name)
+	if err != nil {
+		return fmt.Errorf("reading migration %s: %w", name, err)
+	}
+
+	err = tx.Exec(string(script)).Error
+	if err != nil {
+		return fmt.Errorf("applying migration %s: %w", name, err)
+	}
+
+	return nil
+}