varconf配置中心后端代码（varconf是基于golang的分布式统一配置中-varconf-server.zip

# Go-MySQL-Driver A MySQL-Driver for Go's [database/sql](https://golang.org/pkg/database/sql/) package  --------------------------------------- * [Features](#features) * [Requirements](#requirements) * [Installation](#installation) * [Usage](#usage) * [DSN (Data Source Name)](#dsn-data-source-name) * [Password](#password) * [Protocol](#protocol) * [Address](#address) * [Parameters](#parameters) * [Examples](#examples) * [Connection pool and timeouts](#connection-pool-and-timeouts) * [context.Context Support](#contextcontext-support) * [ColumnType Support](#columntype-support) * [LOAD DATA LOCAL INFILE support](#load-data-local-infile-support) * [time.Time support](#timetime-support) * [Unicode support](#unicode-support) * [Testing / Development](#testing--development) * [License](#license) --------------------------------------- ## Features * Lightweight and [fast](https://github.com/go-sql-driver/sql-benchmark "golang MySQL-Driver performance") * Native Go implementation. No C-bindings, just pure Go * Connections over TCP/IPv4, TCP/IPv6, Unix domain sockets or [custom protocols](https://godoc.org/github.com/go-sql-driver/mysql#DialFunc) * Automatic handling of broken connections * Automatic Connection Pooling *(by database/sql package)* * Supports queries larger than 16MB * Full [`sql.RawBytes`](https://golang.org/pkg/database/sql/#RawBytes) support. * Intelligent `LONG DATA` handling in prepared statements * Secure `LOAD DATA LOCAL INFILE` support with file Whitelisting and `io.Reader` support * Optional `time.Time` parsing * Optional placeholder interpolation ## Requirements * Go 1.10 or higher. We aim to support the 3 latest versions of Go. * MySQL (4.1+), MariaDB, Percona Server, Google CloudSQL or Sphinx (2.2.3+) --------------------------------------- ## Installation Simple install the package to your [$GOPATH](https://github.com/golang/go/wiki/GOPATH "GOPATH") with the [go tool](https://golang.org/cmd/go/ "go command") from shell: ```bash $ go get -u github.com/go-sql-driver/mysql ``` Make sure [Git is installed](https://git-scm.com/downloads) on your machine and in your system's `PATH`. ## Usage _Go MySQL Driver_ is an implementation of Go's `database/sql/driver` interface. You only need to import the driver and can use the full [`database/sql`](https://golang.org/pkg/database/sql/) API then. Use `mysql` as `driverName` and a valid [DSN](#dsn-data-source-name) as `dataSourceName`: ```go import "database/sql" import _ "github.com/go-sql-driver/mysql" db, err := sql.Open("mysql", "user:password@/dbname") ``` [Examples are available in our Wiki](https://github.com/go-sql-driver/mysql/wiki/Examples "Go-MySQL-Driver Examples"). ### DSN (Data Source Name) The Data Source Name has a common format, like e.g. [PEAR DB](http://pear.php.net/manual/en/package.database.db.intro-dsn.php) uses it, but without type-prefix (optional parts marked by squared brackets): ``` [username[:password]@][protocol[(address)]]/dbname[?param1=value1&...&paramN=valueN] ``` A DSN in its fullest form: ``` username:password@protocol(address)/dbname?param=value ``` Except for the databasename, all values are optional. So the minimal DSN is: ``` /dbname ``` If you do not want to preselect a database, leave `dbname` empty: ``` / ``` This has the same effect as an empty DSN string: ``` ``` Alternatively, [Config.FormatDSN](https://godoc.org/github.com/go-sql-driver/mysql#Config.FormatDSN) can be used to create a DSN string by filling a struct. #### Password Passwords can consist of any character. Escaping is **not** necessary. #### Protocol See [net.Dial](https://golang.org/pkg/net/#Dial) for more information which networks are available. In general you should use an Unix domain socket if available and TCP otherwise for best performance. #### Address For TCP and UDP networks, addresses have the form `host[:port]`. If `port` is omitted, the default port will be used. If `host` is a literal IPv6 address, it must be enclosed in square brackets. The functions [net.JoinHostPort](https://golang.org/pkg/net/#JoinHostPort) and [net.SplitHostPort](https://golang.org/pkg/net/#SplitHostPort) manipulate addresses in this form. For Unix domain sockets the address is the absolute path to the MySQL-Server-socket, e.g. `/var/run/mysqld/mysqld.sock` or `/tmp/mysql.sock`. #### Parameters *Parameters are case-sensitive!* Notice that any of `true`, `TRUE`, `True` or `1` is accepted to stand for a true boolean value. Not surprisingly, false can be specified as any of: `false`, `FALSE`, `False` or `0`. ##### `allowAllFiles` ``` Type: bool Valid Values: true, false Default: false ``` `allowAllFiles=true` disables the file Whitelist for `LOAD DATA LOCAL INFILE` and allows *all* files. [*Might be insecure!*](http://dev.mysql.com/doc/refman/5.7/en/load-data-local.html) ##### `allowCleartextPasswords` ``` Type: bool Valid Values: true, false Default: false ``` `allowCleartextPasswords=true` allows using the [cleartext client side plugin](http://dev.mysql.com/doc/en/cleartext-authentication-plugin.html) if required by an account, such as one defined with the [PAM authentication plugin](http://dev.mysql.com/doc/en/pam-authentication-plugin.html). Sending passwords in clear text may be a security problem in some configurations. To avoid problems if there is any possibility that the password would be intercepted, clients should connect to MySQL Server using a method that protects the password. Possibilities include [TLS / SSL](#tls), IPsec, or a private network. ##### `allowNativePasswords` ``` Type: bool Valid Values: true, false Default: true ``` `allowNativePasswords=false` disallows the usage of MySQL native password method. ##### `allowOldPasswords` ``` Type: bool Valid Values: true, false Default: false ``` `allowOldPasswords=true` allows the usage of the insecure old password method. This should be avoided, but is necessary in some cases. See also [the old_passwords wiki page](https://github.com/go-sql-driver/mysql/wiki/old_passwords). ##### `charset` ``` Type: string Valid Values: <name> Default: none ``` Sets the charset used for client-server interaction (`"SET NAMES <value>"`). If multiple charsets are set (separated by a comma), the following charset is used if setting the charset failes. This enables for example support for `utf8mb4` ([introduced in MySQL 5.5.3](http://dev.mysql.com/doc/refman/5.5/en/charset-unicode-utf8mb4.html)) with fallback to `utf8` for older servers (`charset=utf8mb4,utf8`). Usage of the `charset` parameter is discouraged because it issues additional queries to the server. Unless you need the fallback behavior, please use `collation` instead. ##### `checkConnLiveness` ``` Type: bool Valid Values: true, false Default: true ``` On supported platforms connections retrieved from the connection pool are checked for liveness before using them. If the check fails, the respective connection is marked as bad and the query retried with another connection. `checkConnLiveness=false` disables this liveness check of connections. ##### `collation` ``` Type: string Valid Values: <name> Default: utf8mb4_general_ci ``` Sets the collation used for client-server interaction on connection. In contrast to `charset`, `collation` does not issue additional queries. If the specified collation is unavailable on the target server, the connection will fail. A list of valid charsets for a server is retrievable with `SHOW COLLATION`. The default collation (`utf8mb4_general_ci`) is supported from MySQL 5.5. You should use an older collation (e.g. `utf8_general_ci`) for older MySQL. Collations for charset