bring in mysql backend from relayer.

mysql/init.go

@@ -0,0 +1,71 @@
+package mysql
+
+import (
+	"strings"
+
+	"github.com/fiatjaf/eventstore"
+	_ "github.com/go-sql-driver/mysql"
+	"github.com/jmoiron/sqlx"
+	"github.com/jmoiron/sqlx/reflectx"
+)
+
+const (
+	queryLimit        = 100
+	queryIDsLimit     = 500
+	queryAuthorsLimit = 500
+	queryKindsLimit   = 10
+	queryTagsLimit    = 10
+)
+
+var _ eventstore.Storage = (*MySQLBackend)(nil)
+
+var ddls = []string{
+	`CREATE TABLE IF NOT EXISTS event (
+       id char(64) NOT NULL primary key,
+       pubkey char(64) NOT NULL,
+       created_at int NOT NULL,
+       kind integer NOT NULL,
+       tags json NOT NULL,
+       content text NOT NULL,
+       sig text NOT NULL);`,
+	`CREATE INDEX pubkeyprefix ON event (pubkey);`,
+	`CREATE INDEX timeidx ON event (created_at DESC);`,
+	`CREATE INDEX kindidx ON event (kind);`,
+}
+
+func (b *MySQLBackend) Init() error {
+	db, err := sqlx.Connect("mysql", b.DatabaseURL)
+	if err != nil {
+		return err
+	}
+
+	// sqlx default is 0 (unlimited), while mysql by default accepts up to 100 connections
+	db.SetMaxOpenConns(80)
+
+	db.Mapper = reflectx.NewMapperFunc("json", sqlx.NameMapper)
+	b.DB = db
+
+	for _, ddl := range ddls {
+		_, err := b.DB.Exec(ddl)
+		if err != nil && !strings.HasPrefix(err.Error(), `Error 1061: Duplicate key name`) {
+			return err
+		}
+	}
+
+	if b.QueryLimit == 0 {
+		b.QueryLimit = queryLimit
+	}
+	if b.QueryIDsLimit == 0 {
+		b.QueryIDsLimit = queryIDsLimit
+	}
+	if b.QueryAuthorsLimit == 0 {
+		b.QueryAuthorsLimit = queryAuthorsLimit
+	}
+	if b.QueryKindsLimit == 0 {
+		b.QueryKindsLimit = queryKindsLimit
+	}
+	if b.QueryTagsLimit == 0 {
+		b.QueryTagsLimit = queryTagsLimit
+	}
+	return err
+}