feat: add logging and collector implementations

- Introduced `hertzx` package with `NewHertz` function for server initialization.
- Implemented `logx` package with various log collectors: Console, Loki, Elasticsearch, and Prometheus.
- Added `Logger` struct to manage logging levels and collectors.
- Created environment variable loading functionality in `osx` package to support configuration.
- Enhanced logging capabilities with structured log entries and asynchronous collection.

dbx/postgres.go

@@ -0,0 +1,70 @@
+package dbx
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"gorm.io/driver/postgres"
+	"gorm.io/gorm"
+)
+
+func GetPostgresDB(cfg *DBConfig, dbName string) *gorm.DB {
+	db, err := getPostgresInstance(cfg, dbName)
+	if err != nil {
+		panic("failed to connect to Postgres database: " + err.Error())
+	}
+	return db
+}
+
+func getPostgresInstance(cfg *DBConfig, dbName string) (*gorm.DB, error) {
+	targetDSN := fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=%s",
+		cfg.Host, cfg.Port, cfg.User, cfg.Password, dbName, cfg.Sslmode)
+
+	// 先尝试直接连接目标库
+	if db, err := gorm.Open(postgres.Open(targetDSN), &gorm.Config{}); err == nil {
+		return db, nil
+	}
+
+	// 连接 admin DB（postgres）
+	adminDSN := fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=postgres sslmode=%s",
+		cfg.Host, cfg.Port, cfg.User, cfg.Password, cfg.Sslmode)
+	adminDB, err := gorm.Open(postgres.Open(adminDSN), &gorm.Config{})
+	if err != nil {
+		return nil, fmt.Errorf("connect admin postgres failed: %w", err)
+	}
+	// 确保关闭底层连接
+	if sqlDB, e := adminDB.DB(); e == nil {
+		defer sqlDB.Close()
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// 检查是否存在
+	var count int64
+	if err := adminDB.WithContext(ctx).Raw("SELECT count(*) FROM pg_database WHERE datname = ?", dbName).Scan(&count).Error; err != nil {
+		return nil, fmt.Errorf("check database existence failed: %w", err)
+	}
+	if count == 0 {
+		ident := escapePostgresIdentifier(dbName)
+		createSQL := fmt.Sprintf("CREATE DATABASE %s", ident)
+		if err := adminDB.WithContext(ctx).Exec(createSQL).Error; err != nil {
+			return nil, fmt.Errorf("create database %s failed: %w", dbName, err)
+		}
+	}
+
+	// 尝试连接目标数据库
+	db2, err := gorm.Open(postgres.Open(targetDSN), &gorm.Config{})
+	if err != nil {
+		return nil, fmt.Errorf("connect target after create failed: %w", err)
+	}
+	return db2, nil
+}
+
+// 辅助：安全转义 Postgres 标识符（用双引号并把 " 替换为 ""）
+func escapePostgresIdentifier(s string) string {
+	s = strings.ReplaceAll(s, `"`, `""`)
+	return `"` + s + `"`
+}