init

internal/db/migrate.go

@@ -0,0 +1,72 @@
+package db
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+func RunMigrations(ctx context.Context, pool *pgxpool.Pool, dir string) error {
+	if _, err := pool.Exec(ctx, `
+		create table if not exists schema_migrations (
+			filename text primary key,
+			applied_at timestamptz not null default now()
+		)
+	`); err != nil {
+		return fmt.Errorf("create schema_migrations: %w", err)
+	}
+
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return fmt.Errorf("read migrations dir: %w", err)
+	}
+
+	var files []string
+	for _, entry := range entries {
+		if entry.IsDir() || filepath.Ext(entry.Name()) != ".sql" {
+			continue
+		}
+		files = append(files, entry.Name())
+	}
+	sort.Strings(files)
+
+	for _, name := range files {
+		var exists bool
+		if err := pool.QueryRow(ctx, `select exists(select 1 from schema_migrations where filename = $1)`, name).Scan(&exists); err != nil {
+			return fmt.Errorf("check migration %s: %w", name, err)
+		}
+		if exists {
+			continue
+		}
+
+		body, err := os.ReadFile(filepath.Join(dir, name))
+		if err != nil {
+			return fmt.Errorf("read migration %s: %w", name, err)
+		}
+
+		tx, err := pool.Begin(ctx)
+		if err != nil {
+			return fmt.Errorf("begin migration %s: %w", name, err)
+		}
+
+		if _, err := tx.Exec(ctx, string(body)); err != nil {
+			_ = tx.Rollback(ctx)
+			return fmt.Errorf("execute migration %s: %w", name, err)
+		}
+
+		if _, err := tx.Exec(ctx, `insert into schema_migrations (filename) values ($1)`, name); err != nil {
+			_ = tx.Rollback(ctx)
+			return fmt.Errorf("record migration %s: %w", name, err)
+		}
+
+		if err := tx.Commit(ctx); err != nil {
+			return fmt.Errorf("commit migration %s: %w", name, err)
+		}
+	}
+
+	return nil
+}