feat: 对接 PostgreSQL 存储层

backend/internal/store/migrate.go

@@ -0,0 +1,80 @@
+package store
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"sort"
+	"strings"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"github.com/hhs/camtalk/internal/logger"
+)
+
+// RunMigrations 从给定的 fs.FS 中读取 *.up.sql 文件并按版本号顺序执行。
+// 已执行过的版本会跳过（通过 schema_migrations 表记录）。
+func RunMigrations(ctx context.Context, pool *pgxpool.Pool, fsys fs.FS) error {
+	// 确保 schema_migrations 表存在
+	if _, err := pool.Exec(ctx, `CREATE TABLE IF NOT EXISTS schema_migrations (
+		version INTEGER PRIMARY KEY,
+		applied_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+	)`); err != nil {
+		return fmt.Errorf("create schema_migrations table: %w", err)
+	}
+
+	// 收集所有 *.up.sql 文件
+	entries, err := fs.ReadDir(fsys, ".")
+	if err != nil {
+		return fmt.Errorf("read migrations dir: %w", err)
+	}
+
+	var files []string
+	for _, e := range entries {
+		if !e.IsDir() && strings.HasSuffix(e.Name(), ".up.sql") {
+			files = append(files, e.Name())
+		}
+	}
+	sort.Strings(files)
+
+	for _, name := range files {
+		// 从文件名提取版本号，如 "001_users.up.sql" → 1
+		var version int
+		if _, err := fmt.Sscanf(name, "%d_", &version); err != nil {
+			return fmt.Errorf("parse version from %s: %w", name, err)
+		}
+
+		// 检查是否已执行
+		var exists bool
+		if err := pool.QueryRow(ctx,
+			`SELECT EXISTS(SELECT 1 FROM schema_migrations WHERE version = $1)`, version,
+		).Scan(&exists); err != nil {
+			return fmt.Errorf("check migration version %d: %w", version, err)
+		}
+		if exists {
+			logger.Log.Debugw("migration already applied", "version", version, "file", name)
+			continue
+		}
+
+		// 读取并执行
+		content, err := fs.ReadFile(fsys, name)
+		if err != nil {
+			return fmt.Errorf("read migration %s: %w", name, err)
+		}
+
+		if _, err := pool.Exec(ctx, string(content)); err != nil {
+			return fmt.Errorf("execute migration %s: %w", name, err)
+		}
+
+		// 记录已执行
+		if _, err := pool.Exec(ctx,
+			`INSERT INTO schema_migrations (version) VALUES ($1)`, version,
+		); err != nil {
+			return fmt.Errorf("record migration %d: %w", version, err)
+		}
+
+		logger.Log.Infow("migration applied", "version", version, "file", name)
+	}
+
+	return nil
+}