wangjia
86 lines
2.4 KiB
Go
86 lines
2.4 KiB
Go
package store
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import (
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"database/sql"
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"fmt"
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"time"
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// Register the mysql driver with database/sql.
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"github.com/go-sql-driver/mysql"
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_ "github.com/go-sql-driver/mysql"
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"github.com/wangjia/pangolin/server/internal/config"
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)
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// Open is the single canonical MySQL entry point for the Pangolin server.
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//
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// It:
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// 1. Parses the DSN from cfg.DSN.
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// 2. Structurally overrides UTC parameters (ParseTime, Loc, Collation,
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// time_zone session variable) — no string manipulation.
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// 3. Configures the connection pool.
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// 4. Pings the server.
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// 5. Asserts SELECT @@session.time_zone = "+00:00" (startup fatal if the
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// server ignores our DSN override — e.g. SQL mode forces a different TZ).
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func Open(cfg *config.Config) (*sql.DB, error) {
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dsn, err := buildDSN(cfg)
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if err != nil {
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return nil, fmt.Errorf("store.Open: %w", err)
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}
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db, err := sql.Open("mysql", dsn)
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if err != nil {
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return nil, fmt.Errorf("store.Open: %w", err)
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}
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// Connection pool.
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db.SetMaxOpenConns(30)
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db.SetMaxIdleConns(10)
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db.SetConnMaxLifetime(5 * time.Minute)
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if err := db.Ping(); err != nil {
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_ = db.Close()
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return nil, fmt.Errorf("store.Open: ping: %w", err)
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}
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// Hard assertion: the session time_zone must be "+00:00".
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// This catches MySQL servers that ignore client-supplied time_zone params.
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var tz string
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if err := db.QueryRow("SELECT @@session.time_zone").Scan(&tz); err != nil {
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_ = db.Close()
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return nil, fmt.Errorf("store.Open: query @@session.time_zone: %w", err)
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}
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if tz != "+00:00" {
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_ = db.Close()
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return nil, fmt.Errorf(
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"store.Open: session time_zone=%q, want +00:00; UTC DSN override failed",
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tz,
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)
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}
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return db, nil
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}
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// buildDSN parses cfg.DSN and structurally overrides UTC and utf8mb4
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// parameters regardless of what the caller supplied.
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// This is a pure function and is tested independently.
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func buildDSN(cfg *config.Config) (string, error) {
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dsnCfg, err := mysql.ParseDSN(cfg.DSN)
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if err != nil {
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return "", fmt.Errorf("buildDSN: parse DSN: %w", err)
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}
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// Force UTC — overwrite any caller-supplied values (structural, not string).
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dsnCfg.ParseTime = true
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dsnCfg.Loc = time.UTC
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// Collation implicitly sets charset to utf8mb4 via SET NAMES.
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dsnCfg.Collation = "utf8mb4_unicode_ci"
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if dsnCfg.Params == nil {
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dsnCfg.Params = make(map[string]string)
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}
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// The time_zone connection parameter sends SET time_zone = '+00:00' on connect.
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dsnCfg.Params["time_zone"] = "'+00:00'"
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return dsnCfg.FormatDSN(), nil
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}
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