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这篇文章主要介绍 docker 中 info 命令请求流程分析，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！
先上一个流程图示
仅供自己梳理了解最新代码流程，有些细节并不会展开深挖
1、进入客户端接收代码块，由 runInfo 方法返回内容
github.com/docker/cli/cli/command/system/info.go
// NewInfoCommand creates a new cobra.Command for `docker info`
func NewInfoCommand(dockerCli command.Cli) *cobra.Command {
var opts infoOptions
cmd := cobra.Command{ Use: info [OPTIONS] ,
Short: Display system-wide information ,
Args: cli.NoArgs,
RunE: func(cmd *cobra.Command, args []string) error { return runInfo(dockerCli, opts)
},
}
func runInfo(dockerCli command.Cli, opts *infoOptions) error { ctx := context.Background()
info, err := dockerCli.Client().Info(ctx)
2、 请求转发给 docker daemon 处理
github.com/docker/cli/vendor/github.com/docker/docker/client/info.go
// Info returns information about the docker server.
func (cli *Client) Info(ctx context.Context) (types.Info, error) {
var info types.Info
serverResp, err := cli.get(ctx, /info , url.Values{}, nil)3、docker daemon 的监听路由，进入到 SystemInfo 处理
github.com/docker/docker/api/server/router/system/system.go
// NewRouter initializes a new system router
func NewRouter(b Backend, c ClusterBackend, fscache *fscache.FSCache, builder *buildkit.Builder, features *map[string]bool) router.Router { router.NewGetRoute( /info , r.getInfo),github.com/docker/docker/api/server/router/system/system_routes.go
func (s *systemRouter) getInfo(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error { info, err := s.backend.SystemInfo()4、经过进入 systemInfo 处理方法，可知 container 状态信息是已经在内存中数据
github.com/docker/docker/daemon/info.go
// SystemInfo returns information about the host server the daemon is running on.
func (daemon *Daemon) SystemInfo() (*types.Info, error) { sysInfo := sysinfo.New(true)
cRunning, cPaused, cStopped := stateCtr.get()
v := types.Info{
ID: daemon.ID,
Containers: cRunning + cPaused + cStopped,
ContainersRunning: cRunning,
ContainersPaused: cPaused,
ContainersStopped: cStopped,5、找到设置 container 运行状态的数据方法
github.com/docker/docker/daemon/metrics.go
func (ctr *stateCounter) set(id, label string) { ctr.mu.Lock()
ctr.states[id] = label
ctr.mu.Unlock()}6、容器状态数据来源
6.1、顺着设置方法找到在创建 container 时会设置一条数据，这是初始化的数据
github.com/docker/docker/daemon/create.go
// Create creates a new container from the given configuration with a given name.
func (daemon *Daemon) create(params types.ContainerCreateConfig, managed bool) (retC *container.Container, retErr error) { stateCtr.set(container.ID, stopped)6.2、容器操作（暂停、启动、恢复）
github.com/docker/docker/daemon/pause.go
// containerPause pauses the container execution without stopping the process.
// The execution can be resumed by calling containerUnpause.
func (daemon *Daemon) containerPause(container *container.Container) error {
container.Paused = true
daemon.setStateCounter(container)github.com/docker/docker/daemon/start.go
// containerStart prepares the container to run by setting up everything the
// container needs, such as storage and networking, as well as links
// between containers. The container is left waiting for a signal to
// begin running.
func (daemon *Daemon) containerStart(container *container.Container, checkpoint string, checkpointDir string, resetRestartManager bool) (err error) { container.SetRunning(pid, true)
container.HasBeenManuallyStopped = false
container.HasBeenStartedBefore = true
daemon.setStateCounter(container)github.com/docker/docker/daemon/unpause.go
// containerUnpause resumes the container execution after the container is paused.
func (daemon *Daemon) containerUnpause(container *container.Container) error {
container.Paused = false
daemon.setStateCounter(container)6.3、docker 重启后，从目录中获取容器状态
github.com/docker/docker/daemon/daemon.go
func (daemon *Daemon) restore() error {
for _, c := range containers {
// 从文件 config.v2.json 中获取容器状态
daemon.setStateCounter(c)
// 如文件中的状态是运行或暂停，再进行检查，并重置状态
if c.IsRunning() || c.IsPaused() {
default:
// running
c.Lock()
c.Paused = false
daemon.setStateCounter(c)7、事件变更重置容器状态（windows)
7.1、container 状态变更的信息方法
github.com/docker/docker/daemon/monitor.go
func (daemon *Daemon) setStateCounter(c *container.Container) { switch c.StateString() {
case paused :
stateCtr.set(c.ID, paused)
case running :
stateCtr.set(c.ID, running)
default:
stateCtr.set(c.ID, stopped)
}
}7.2、windows 事件监听
github.com/docker/docker/daemon/monitor.go
// ProcessEvent is called by libcontainerd whenever an event occurs
func (daemon *Daemon) ProcessEvent(id string, e libcontainerd.EventType, ei libcontainerd.EventInfo) error {
case libcontainerd.EventExit:
daemon.setStateCounter(c)
case libcontainerd.EventStart:
// This is here to handle start not generated by docker
if !c.Running { c.SetRunning(int(ei.Pid), false)
c.HasBeenManuallyStopped = false
c.HasBeenStartedBefore = true
daemon.setStateCounter(c)
case libcontainerd.EventPaused:
if !c.Paused {
c.Paused = true
daemon.setStateCounter(c)
case libcontainerd.EventResumed:
if c.Paused {
c.Paused = false
daemon.setStateCounter(c)8、开启启动 docker 时的 debug 模式，获取文件描述、goroute 等信息
dockerd –debug
github.com/docker/cli/cli/command/system/info.go
if info.Debug { fmt.Fprintln(dockerCli.Out(), File Descriptors: , info.NFd)
fmt.Fprintln(dockerCli.Out(), Goroutines: , info.NGoroutines)
fmt.Fprintln(dockerCli.Out(), System Time: , info.SystemTime)
fmt.Fprintln(dockerCli.Out(), EventsListeners: , info.NEventsListener)
}以上是“docker 中 info 命令请求流程分析”这篇文章的所有内容，感谢各位的阅读！希望分享的内容对大家有帮助，更多相关知识，欢迎关注丸趣 TV 行业资讯频道！
