TiUP 源码初探
想必tidber都使用过tiup，tiup给部署带来很大的便利性，在日常开发中也会涉及到分布式的部署，自己难免也会写一些工具，本文抛砖引玉，分享一下自己看tiup源码的一些步骤，希望您在看源码或写工具时多一个思考方向。环境部署可参考：启航TiDB：调试环境搭建（vscode+wsl+pd）
Cobra
Cobra 是一个 Go 语言开发的命令行（CLI）框架，是由 Go 团队成员 spf13 为 Hugo 项目创建的，并已被许多流行的 Go 项目所采用，如 Kubernetes、Helm、Docker (distribution)、Etcd 等。而Tiup也是以cobra为基础，进行开发的。网上有大量的介绍文章，这里就不赘述了，直接放一个简单的demo。
demo
├── cmd
│ └── root.go
| └── version.go
├── go.mod
├── go.sum
└── main.go
// root.go
var (
rootCmd *cobra.Command
)
func init() {
rootCmd = &cobra.Command{
Use: "demo",
Short: "Demo is a Cobra application",
Long: `This is a demo application to illustrate the use of Cobra library.`,
Run: func(cmd *cobra.Command, args []string) {
fmt.Println("Hello, Cobra!")
},
}
rootCmd.AddCommand(newVersionCmd())
}
func Execute() {
if err := rootCmd.Execute(); err != nil {
fmt.Println(err)
os.Exit(1)
}
}
// version.go
func newVersionCmd() *cobra.Command {
cmd := &cobra.Command{
Use: "version",
Short: "Print the version number of Demo",
Long: `All software has versions. This is Demo's`,
Run: func(cmd *cobra.Command, args []string) {
fmt.Println("Demo v0.1 -- HEAD")
},
}
return cmd
}
func init() {
rootCmd.AddCommand(versionCmd)
}
// main.go
func main() {
cmd.Execute()
}
编译后运行
> .\\demo.exe -h
This is a demo application to illustrate the use of Cobra library.
Usage:
demo [flags]
demo [command]
Available Commands:
completion Generate the autocompletion script for the specified shell
help Help about any command
version Print the version number of Demo
Flags:
-h, --help help for demo
Use "demo [command] --help" for more information about a command.
同样，Tiup的组织结构也很简单明确，在cmd文件夹下放着各种命令，root.go为注册命令的地方，目录结构如下:
├── cmd
│ ├── env.go
│ ├── list.go
│ ├── mirror.go
│ ├── root.go # 命令注册
├── components # 组件
│ ├── bench
│ ├── cluster
| | |── command
| | │ ├── clean.go
| | │ ├── deploy.go
| | │ ├── root.go # cluster 命令注册
| | |—— main.go
│ └── playground
├── pkg
│ ├── cluster
│ │ ├── ansible
│ │ ├── api
│ │ ├── audit
│ │ ├── clusterutil
│ │ ├── ctxt
│ │ ├── executor # 执行器，easyssh和nativessh
│ │ ├── manager # 任务的生成，步骤的生成所有的管理都在这里
│ │ ├── module
│ │ ├── operation
│ │ ├── spec # 拓扑结构--安装的说明书
│ │ ├── task # 各种任务
│ │ └── template #
├── main.go
和demo不同的是，Tiup的二级命令是通过调用对应的执行文件来实现，这些执行文件在$TIUPHOME/components/cluster/vx.x.x/下，在执行的时候如果没有对应的子命令就会下载（只用tiup-cluster,就不会有tiup-dm），另一个好处是每一个子命令都是一个独立的命令行工具—可插拔组件。
// root.go
func init() {
cobra.EnableCommandSorting = false
_ = os.Setenv(localdata.EnvNameTelemetryEventUUID, eventUUID)
rootCmd = &cobra.Command{
Use: `tiup [flags] [args...]`
// ...
},
PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
// InitEnv
return nil
},
RunE: func(cmd *cobra.Command, args []string) error {
if len(args) == 0 {
return cmd.Help()
}
env := environment.GlobalEnv()
// ...
return tiupexec.RunComponent(env, tag, componentSpec, binPath, args)
},
}
}
而这些命令最小的执行单位是任务。
任务
任务会有执行和回滚两个操作，在操作的时候有顺序和并行的两种任务，builder来构建不同的任务
type (
// Task represents a operation while TiUP execution
Task interface {
fmt.Stringer
Execute(ctx context.Context) error
Rollback(ctx context.Context) error
}
// Serial will execute a bundle of task in serialized way
Serial struct {
ignoreError bool
hideDetailDisplay bool
inner []Task
}
// Parallel will execute a bundle of task in parallelism way
Parallel struct {
ignoreError bool
hideDetailDisplay bool
inner []Task
}
)
任务也可以作为一种方法为其它任务调用比如：CopyComponent，任务最后都会调用执行器来结束任务，其实就是linux上的命令。
func (m *Mkdir) Execute(ctx context.Context) error {
exec, found := ctxt.GetInner(ctx).GetExecutor(m.host)
// ...
_, _, err := exec.Execute(ctx, cmd, m.sudo) // use root to create the dir
if err != nil {
return errors.Trace(err)
}
// ...
return nil
}
func (c *CopyComponent) Execute(ctx context.Context) error {
// ...
install := &InstallPackage{
srcPath: srcPath,
host: c.host,
dstDir: c.dstDir,
}
return install.Execute(ctx)
}
func (c *InstallPackage) Execute(ctx context.Context) error {
// Install package to remote server
exec, found := ctxt.GetInner(ctx).GetExecutor(c.host)
if !found {
return ErrNoExecutor
}
dstDir := filepath.Join(c.dstDir, "bin")
dstPath := filepath.Join(dstDir, path.Base(c.srcPath))
err := exec.Transfer(ctx, c.srcPath, dstPath, false, 0, false)
if err != nil {
return errors.Annotatef(err, "failed to scp %s to %s:%s", c.srcPath, c.host, dstPath)
}
cmd := fmt.Sprintf(`tar --no-same-owner -zxf %s -C %s && rm %s`, dstPath, dstDir, dstPath)
_, stderr, err := exec.Execute(ctx, cmd, false)
if err != nil {
return errors.Annotatef(err, "stderr: %s", string(stderr))
}
return nil
}
执行器
执行器放在上下文上的，它包含两个方法，执行器的设置是在需要SSH的时候，比如下面的RootSSH
Executor interface {
Execute(ctx context.Context, cmd string, sudo bool, timeout ...time.Duration) (stdout []byte, stderr []byte, err error)
Transfer(ctx context.Context, src, dst string, download bool, limit int, compress bool) error
}
// Execute implements the Task interface
func (s *RootSSH) Execute(ctx context.Context) error {
// ...
e, err := executor.New(s.sshType, s.sudo, sc)
if err != nil {
return err
}
ctxt.GetInner(ctx).SetExecutor(s.host, e)
return nil
}
执行器有easyssh和nativessh两种
// Deploy a cluster.
func (m *Manager) Deploy(
name string,
clusterVersion string,
topoFile string,
opt DeployOptions,
afterDeploy func(b *task.Builder, newPart spec.Topology, gOpt operator.Options),
skipConfirm bool,
gOpt operator.Options,
) error
操作
可以看到tiup的基础就是任务，任务结束于执行器—ssh，多个任务就合并成一个步骤，多个步骤组合成一个操作：task.NewBuilder(m.logger).Atask().Btask.AS，下面我们看一个实际的操作Deploy
每一个操作都放在manager文件夹下，这里以Deploy为例，可以看到任务组一般都是以ssh任务开始，显示任务结束。
// command/root.go
func init() {
rootCmd.AddCommand(
newCheckCmd(),
newDeploy(),
// ...
)
}
// command/deploy.go
func newDeploy() *cobra.Command {
opt := manager.DeployOptions{
IdentityFile: path.Join(utils.UserHome(), ".ssh", "id_rsa"),
}
cmd := &cobra.Command{
Use: "deploy ",
Short: "Deploy a cluster for production",
Long: "Deploy a cluster for production. SSH connection will be used to deploy files, as well as creating system users for running the service.",
SilenceUsage: true,
RunE: func(cmd *cobra.Command, args []string) error {
// ...
return cm.Deploy(clusterName, version, topoFile, opt, postDeployHook, skipConfirm, gOpt)
},
}
// ...
cmd.Flags().BoolVarP(&opt.NoLabels, "no-labels", "", false, "Don't check TiKV labels")
return cmd
}
// manager/deploy.go
func (m *Manager) Deploy(
name string,
clusterVersion string,
topoFile string,
opt DeployOptions,
afterDeploy func(b *task.Builder, newPart spec.Topology, gOpt operator.Options),
skipConfirm bool,
gOpt operator.Options,
) error {
// ...
var (
envInitTasks []*task.StepDisplay // tasks which are used to initialize environment
downloadCompTasks []*task.StepDisplay // tasks which are used to download components
deployCompTasks []*task.StepDisplay // tasks which are used to copy components to remote host
)
// ...
t := task.NewBuilder(m.logger).
RootSSH(
host,
hostInfo.ssh,
opt.User,
sshConnProps.Password,
// ...,
).
EnvInit(host, globalOptions.User, globalOptions.Group, opt.SkipCreateUser || globalOptions.User == opt.User, sudo).
Mkdir(globalOptions.User, host, sudo, dirs...).
BuildAsStep(fmt.Sprintf(" - Prepare %s:%d", host, hostInfo.ssh))
envInitTasks = append(envInitTasks, t)
// ...
builder := task.NewBuilder(m.logger).
Step("+ Generate SSH keys",
task.NewBuilder(m.logger).
SSHKeyGen(m.specManager.Path(name, "ssh", "id_rsa")).
Build(),
m.logger).
ParallelStep("+ Download TiDB components", false, downloadCompTasks...).
ParallelStep("+ Initialize target host environments", false, envInitTasks...).
ParallelStep("+ Deploy TiDB instance", false, deployCompTasks...).
ParallelStep("+ Copy certificate to remote host", gOpt.Force, certificateTasks...).
ParallelStep("+ Init instance configs", gOpt.Force, refreshConfigTasks...).
ParallelStep("+ Init monitor configs", gOpt.Force, monitorConfigTasks...)
// ...
m.logger.Infof("Cluster `%s` deployed successfully, you can start it with command: `%s`", name, hint)
return nil
}
