Memos 数据库启动过程源码分析
3 min read

Memos 数据库启动过程源码分析

memos 支持多种数据库后端, 以 SQLite 和 MySQL driver 为例分析清楚 Memos 是如何实现数据库启动的相关逻辑
Memos 数据库启动过程源码分析
Photo by Kevin Ku on Unsplash

因为碰到了 Memos Heatmap 显示统计数据不准确的问题(comment memos 没有被纳入统计),为了理解 GetMemosList 的工作原理需要阅读源码理解清楚 Memos server 端特别是涉及到数据库的逻辑是什么样。这篇文章就是记录一下 Memos 数据库相关的设计和源码分析。

memos 数据库初始化

// 1. memos service 启动逻辑
main --> cmd.Execute --> rootCmd.Execute --> db.NewDBDriver --> dbDriver.Migrate --> store.New --> server.NewServer --> s.Start

// 2. 配置文件解析逻辑
// profile 初始化,memos.go `init` 函数中完成,主要是通过 `viper` 全局变量绑定命令行参数

// 3. 数据库初始化
// 数据库初始化,以 sqlite 为例(memos 在 store 目录中实现了多种数据库支持)
db.NewDBDriver --> sqlite.NewDB(profile) --> dbDriver.Migrate --> 
	(1) sqlite db 文件不存在:--> applyLatestSchema (即执行 sqlite/migration/LATEST__SCHEMA.sql)
	(2) sqlite db 文件存在:--> FindMigrationHistoryList --> applyMigrationForMinorVersion(即执行 sqlite/migration/${minor-version}/*.sql)

// 4. RPC server 启动逻辑
// Server 启动,至此数据库启动已经完成暂不做后面的源码分析

memos 库表设计

根据 memos 数据库初始化的流程分析,可以发现 memos 数据库表设计主要在 LATEST__SCHEMA.sql 文件中实现,具体可以参考 ${database type}/migration/prod/LATEST__SCHEMA.sql 文件:

-- drop all tables first
DROP TABLE IF EXISTS `migration_history`;
DROP TABLE IF EXISTS `system_setting`;
DROP TABLE IF EXISTS `user`;
DROP TABLE IF EXISTS `user_setting`;
DROP TABLE IF EXISTS `memo`;
DROP TABLE IF EXISTS `memo_organizer`;
DROP TABLE IF EXISTS `memo_relation`;
DROP TABLE IF EXISTS `resource`;
DROP TABLE IF EXISTS `tag`;
DROP TABLE IF EXISTS `activity`;
DROP TABLE IF EXISTS `storage`;
DROP TABLE IF EXISTS `idp`;
DROP TABLE IF EXISTS `inbox`;
DROP TABLE IF EXISTS `webhook`;

-- migration_history
CREATE TABLE `migration_history` (
  `version` VARCHAR(256) NOT NULL PRIMARY KEY,
  `created_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

-- system_setting
CREATE TABLE `system_setting` (
  `name` VARCHAR(256) NOT NULL PRIMARY KEY,
  `value` LONGTEXT NOT NULL,
  `description` TEXT NOT NULL
);

-- user
CREATE TABLE `user` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `created_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `row_status` VARCHAR(256) NOT NULL DEFAULT 'NORMAL',
  `username` VARCHAR(256) NOT NULL UNIQUE,
  `role` VARCHAR(256) NOT NULL DEFAULT 'USER',
  `email` VARCHAR(256) NOT NULL DEFAULT '',
  `nickname` VARCHAR(256) NOT NULL DEFAULT '',
  `password_hash` VARCHAR(256) NOT NULL,
  `avatar_url` LONGTEXT NOT NULL
);

-- user_setting
CREATE TABLE `user_setting` (
  `user_id` INT NOT NULL,
  `key` VARCHAR(256) NOT NULL,
  `value` LONGTEXT NOT NULL,
  UNIQUE(`user_id`,`key`)
);

-- memo
CREATE TABLE `memo` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `creator_id` INT NOT NULL,
  `created_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `row_status` VARCHAR(256) NOT NULL DEFAULT 'NORMAL',
  `content` TEXT NOT NULL,
  `visibility` VARCHAR(256) NOT NULL DEFAULT 'PRIVATE'
);

-- memo_organizer
CREATE TABLE `memo_organizer` (
  `memo_id` INT NOT NULL,
  `user_id` INT NOT NULL,
  `pinned` INT NOT NULL DEFAULT '0',
  UNIQUE(`memo_id`,`user_id`)
);

-- memo_relation
CREATE TABLE `memo_relation` (
  `memo_id` INT NOT NULL,
  `related_memo_id` INT NOT NULL,
  `type` VARCHAR(256) NOT NULL,
  UNIQUE(`memo_id`,`related_memo_id`,`type`)
);

-- resource
CREATE TABLE `resource` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `creator_id` INT NOT NULL,
  `created_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `filename` TEXT NOT NULL,
  `blob` MEDIUMBLOB,
  `external_link` TEXT NOT NULL,
  `type` VARCHAR(256) NOT NULL DEFAULT '',
  `size` INT NOT NULL DEFAULT '0',
  `internal_path` VARCHAR(256) NOT NULL DEFAULT '',
  `memo_id` INT DEFAULT NULL
);

-- tag
CREATE TABLE `tag` (
  `name` VARCHAR(256) NOT NULL,
  `creator_id` INT NOT NULL,
  UNIQUE(`name`,`creator_id`)
);

-- activity
CREATE TABLE `activity` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `creator_id` INT NOT NULL,
  `created_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `type` VARCHAR(256) NOT NULL DEFAULT '',
  `level` VARCHAR(256) NOT NULL DEFAULT 'INFO',
  `payload` TEXT NOT NULL
);

-- storage
CREATE TABLE `storage` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `name` VARCHAR(256) NOT NULL,
  `type` VARCHAR(256) NOT NULL,
  `config` TEXT NOT NULL
);

-- idp
CREATE TABLE `idp` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `name` TEXT NOT NULL,
  `type` TEXT NOT NULL,
  `identifier_filter` VARCHAR(256) NOT NULL DEFAULT '',
  `config` TEXT NOT NULL
);

-- inbox
CREATE TABLE `inbox` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `created_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `sender_id` INT NOT NULL,
  `receiver_id` INT NOT NULL,
  `status` TEXT NOT NULL,
  `message` TEXT NOT NULL
);

-- webhook
CREATE TABLE `webhook` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `created_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_ts` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `row_status` VARCHAR(256) NOT NULL DEFAULT 'NORMAL',
  `creator_id` INT NOT NULL,
  `name` TEXT NOT NULL,
  `url` TEXT NOT NULL
);

可以看出 memos 的库表设计比较简单,唯一值得解释一下的是为跟 user 强相关的数据采用了 UNIQUE 进行了唯一索引的约束。

References

  1. edonyzpc/memos

Public discussion