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[mydocker]---实现查看运行中容器

[mydocker]---实现查看运行中容器

作者: nicktming | 来源:发表于2019-05-11 09:58 被阅读0次

    1. 准备工作

    1.1 准备环境

    root@nicktming:~/go/src/github.com/nicktming/mydocker# git clone https://github.com/nicktming/mydocker.git
root@nicktming:~/go/src/github.com/nicktming/mydocker# git checkout code-5.1
root@nicktming:~/go/src/github.com/nicktming/mydocker# git checkout -b dev-5.2

    1.2 准备busybox.tar

    // 前提条件
root@nicktming:/nicktming# pwd
/nicktming
root@nicktming:/nicktming# ls
busybox.tar

    1.3 预期效果

    root@nicktming:~/go/src/github.com/nicktming/mydocker# git clone https://github.com/nicktming/mydocker.git
root@nicktming:~/go/src/github.com/nicktming/mydocker# git checkout code-5.2
root@nicktming:~/go/src/github.com/nicktming/mydocker# go build .
root@nicktming:~/go/src/github.com/nicktming/mydocker# ./mydocker run -d /bin/top
root@nicktming:~/go/src/github.com/nicktming/mydocker# ./mydocker run -d -name test /bin/top
root@nicktming:~/go/src/github.com/nicktming/mydocker# ./mydocker ps
ID                     NAME                   PID         STATUS      COMMAND     CREATED
15549996015865478061   15549996015865478061   1497        running     /bin/top    2019-04-12 00:20:01
15549996129084897981   test                   1526        running     /bin/top    2019-04-12 00:20:12

    2. 方法

    2.1 一些公共方法

    type ContainerInfo struct {
    Pid         string  `json:"pid"`
    Id          string  `json:"id"`
    Name        string  `json:"name"`
    Command     string  `json:"command"`
    CreateTime  string  `json:"createTime"`
    Status      string  `json:"status"`
}

var (
    RUNNING         string = "running"
    STOP            string = "stopped"
    EXIT            string = "exited"
    CONTAINS        string = "/var/run/mydocker"
    INFOLOCATION    string = "/var/run/mydocker/%s"
    CONFIGNAME      string = "config.json"
)

func writeUUID(uuid string)  {
    ioutil.WriteFile("uuid.txt", []byte(uuid), 0644)
}

func readUUID() string {
    data, _ := ioutil.ReadFile("uuid.txt")
    return string(data)
}

    2.2 生成UUID

    生成containerId,就是根据当前时间再连上一些随机数. 方法如下:

    func ContainerUUID() string {
    str := time.Now().UnixNano()
    containerId := fmt.Sprintf("%d%d", str, int(math.Abs(float64(rand.Intn(10)))))
    log.Printf("containerId:%s\n", containerId)
    return containerId
}
func Test001(t *testing.T)  {
    uuid := ContainerUUID()
    //将uuid写入一个文件中 方便测试用一个uuid测试增删改查方法
    writeUUID(uuid)
}

    测试Test001

    root@nicktming:~/go/src/github.com/nicktming/mydocker/command# pwd
/root/go/src/github.com/nicktming/mydocker/command
root@nicktming:~/go/src/github.com/nicktming/mydocker/command# ls
command.go  commit.go  init.go  models.go  run.go  utils.go  utils_test.go
root@nicktming:~/go/src/github.com/nicktming/mydocker/command# ls
command.go  commit.go  init.go  models.go  run.go  utils.go  utils_test.go
root@nicktming:~/go/src/github.com/nicktming/mydocker/command# go test -v utils_test.go -test.run Test001
=== RUN   Test001
2019/04/11 22:24:18 containerId:15549926581106262991
--- PASS: Test001 (0.00s)
PASS
ok      command-line-arguments  0.003s
root@nicktming:~/go/src/github.com/nicktming/mydocker/command# cat uuid.txt 
15549926581106262991
root@nicktming:~/go/src/github.com/nicktming/mydocker/command#

    2.3 保存容器metadata

    将一个容器保存到/var/run/mydocker目录下:

    func RecordContainerInfo(pid, name, id, command string) error {
    containerInfo := &ContainerInfo {
        Pid:        pid,
        Id:         id,
        Name:       name,
        Command:    command,
        CreateTime: time.Now().Format("2006-01-02 15:04:05"),
        Status:     RUNNING,
    }
    jsonInfo, _ := json.Marshal(containerInfo)
    log.Printf("jsonInfo:%s\n", string(jsonInfo))
    location := fmt.Sprintf(INFOLOCATION, name)
    file     := location + "/" + CONFIGNAME
    if err := os.MkdirAll(location, 0622); err != nil {
        return fmt.Errorf("create %s error : %v\n", location, err)
    }

    if err := ioutil.WriteFile(file, []byte(jsonInfo), 0622); err != nil {
        return fmt.Errorf("write %s to %s error:%v\n", jsonInfo, file, err)
    }
    return nil
}

func Test002(t *testing.T)  {
    uuid := readUUID()
    if err := RecordContainerInfo(uuid, uuid, uuid, "/bin/top"); err != nil {
        log.Printf("RecordContainerInfo error : %v\n", err)
    } else {
        log.Printf("write successfully!\n")
    }
}

    测试Test002

    root@nicktming:~/go/src/github.com/nicktming/mydocker/command# go test -v utils_test.go -test.run Test002
=== RUN   Test002
2019/04/11 22:25:36 jsonInfo:{"pid":"15549926581106262991","id":"15549926581106262991","name":"15549926581106262991","command":"/bin/top","createTime":"2019-04-11 22:25:36","status":"running"}
2019/04/11 22:25:36 write successfully!
--- PASS: Test002 (0.00s)
PASS
ok      command-line-arguments  0.003s
----------------------------terminal 02-------------------------------
root@nicktming:/var/run/mydocker# pwd
/var/run/mydocker
root@nicktming:/var/run/mydocker# cat 15549926581106262991/config.json
{"pid":"15549926581106262991","id":"15549926581106262991","name":"15549926581106262991","command":"/bin/top","createTime":"2019-04-11 22:25:36","status":"running"}
root@nicktming:/var/run/mydocker#

    2.4 获取容器metadata

    根据容器名读取容器的metadata

    func GetContainerInfo(name string) (*ContainerInfo, error) {
    location := fmt.Sprintf(INFOLOCATION, name)
    file     := location + "/" + CONFIGNAME
    containerInfo := &ContainerInfo {}
    data, err := ioutil.ReadFile(file)
    if err != nil {
        return nil, fmt.Errorf("read data %s error:%s\n", data, err)
    }
    json.Unmarshal(data, containerInfo)
    return containerInfo, nil
}
func Test003(t *testing.T)  {
    uuid := readUUID()
    containerInfo, _ := GetContainerInfo(uuid)
    if containerInfo != nil {
        log.Printf("Pid:%s, Id:%s, Name:%s, Command:%s, CreateTime:%s, Status:%s\n",
            containerInfo.Pid, containerInfo.Id, containerInfo.Name, containerInfo.Command, containerInfo.CreateTime, containerInfo.Status)
    }
}

    测试Test003如下:

    root@nicktming:~/go/src/github.com/nicktming/mydocker/command# go test -v utils_test.go -test.run Test003
=== RUN   Test003
2019/04/11 22:26:06 Pid:15549926581106262991, Id:15549926581106262991, Name:15549926581106262991, Command:/bin/top, CreateTime:2019-04-11 22:25:36, Status:running
--- PASS: Test003 (0.00s)
PASS
ok      command-line-arguments  0.003s

    2.5 显示所有容器metadata

    显示所有容器的metadata并格式打印

    func Test004(t *testing.T)  {
    ShowAllContainers()
}
func ShowAllContainers() {
    files, err := ioutil.ReadDir(CONTAINS)
    if err != nil {
        fmt.Errorf("readDir error : %v\n", err)
        return
    }
    var containers []*ContainerInfo
    for _, file := range files {
        container, err := GetContainerInfo(file.Name())
        if err != nil {
            log.Printf("ERROR: %v\n", err)
            continue
        }
        containers = append(containers, container)
    }
    w := tabwriter.NewWriter(os.Stdout, 12, 1, 3, ' ', 0)
    fmt.Fprint(w, "ID\tNAME\tPID\tSTATUS\tCOMMAND\tCREATED\n")
    for _, item := range containers {
        fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\n",
            item.Id,
            item.Name,
            item.Pid,
            item.Status,
            item.Command,
            item.CreateTime)
    }
    if err := w.Flush(); err != nil {
        fmt.Errorf("Flush error %v", err)
    }
}

    测试Test004

    root@nicktming:~/go/src/github.com/nicktming/mydocker/command# go test -v utils_test.go -test.run Test004
=== RUN   Test004
ID                     NAME                   PID                    STATUS      COMMAND     CREATED
15549926581106262991   15549926581106262991   15549926581106262991   running     /bin/top    2019-04-11 22:25:36
--- PASS: Test004 (0.00s)
PASS
ok      command-line-arguments  0.003s

    2.6 删除容器metadata

    根据容器名删除某个容器的metadata

    func DeleteContainerInfo(name string) error {
    location := fmt.Sprintf(INFOLOCATION, name)
    if err := os.RemoveAll(location); err != nil {
        return fmt.Errorf("RemoveAll %s error:%v\n", location, err)
    }
    return nil 
}
func Test005(t *testing.T)  {
    uuid := readUUID()
    if err := DeleteContainerInfo(uuid); err != nil {
        log.Printf("DeleteContainerInfo error %v\n", err)
    }
}

    测试Test005

    ----------------------------terminal 01-------------------------------
root@nicktming:/var/run/mydocker# pwd
/var/run/mydocker
root@nicktming:/var/run/mydocker# cat 15549926581106262991/config.json
{"pid":"15549926581106262991","id":"15549926581106262991","name":"15549926581106262991","command":"/bin/top","createTime":"2019-04-11 22:25:36","status":"running"}
root@nicktming:/var/run/mydocker#
----------------------------terminal 02-------------------------------
root@nicktming:~/go/src/github.com/nicktming/mydocker/command# go test -v utils_test.go -test.run Test005
=== RUN   Test005
--- PASS: Test005 (0.00s)
PASS
ok      command-line-arguments  0.002s
----------------------------terminal 01-------------------------------
root@nicktming:/var/run/mydocker# ls
root@nicktming:/var/run/mydocker#

    3. 实现

    有了2中的方法后实现起来就很简单了

    3.1 增加参数容器名字

    在command/command.go中增加参数name

    var RunCommand = cli.Command{
    Name: "run",
    Flags: []cli.Flag {
        ...
        cli.StringFlag{
            Name: "name",
            Usage: "container name",
        },
        ...
    },
    Action: func(c *cli.Context) error {
        ...
        containerName    := c.String("name")
        ...
        Run(command, tty, &cg, rootPath, volumes, containerName)
        return nil
    },
}

    3.2 修改Run方法

    修改command/run.go中的Run方法.

    func Run(command string, tty bool, cg *cgroups.CroupManger, rootPath string, volumes []string, containerName string)  {
    ...
    id := ContainerUUID()
    if containerName == "" {
        containerName = id
    }
    RecordContainerInfo(strconv.Itoa(cmd.Process.Pid), containerName, id, command)

    // false 表明父进程(Run程序)无须等待子进程(Init程序,Init进程后续会被用户程序覆盖)
    if tty {
        cmd.Wait()
        // -it 交互式的时候退出容器时删除容器metadata
        DeleteContainerInfo(containerName)
    }
}

    3.3 增加ps命令

    增加ps命令列出所有正在运行的容器.

    //command/command.go
var ListCommand = cli.Command{
    Name: "ps",
    Action: func(c *cli.Context) error {
        List()
        return nil
    },
}
// command/list.go
func List()  {
    ShowAllContainers()
}
// main.go
func main()  {
    ...
    app.Commands = []cli.Command{
        command.RunCommand,
        command.InitCommand,
        command.CommitCommand,
        command.ListCommand,
    }
    ...
}

    3.4 测试

    root@nicktming:~/go/src/github.com/nicktming/mydocker# go build .
root@nicktming:~/go/src/github.com/nicktming/mydocker# ./mydocker run -d /bin/top
2019/04/11 23:18:01 volume:[]
2019/04/11 23:18:01 rootPath:
2019/04/11 23:18:01 rootPath is empaty, set cmd.Dir by default: /nicktming/mnt
2019/04/11 23:18:02 containerId:15549958821549242021
2019/04/11 23:18:02 jsonInfo:{"pid":"28396","id":"15549958821549242021","name":"15549958821549242021","command":"/bin/top","createTime":"2019-04-11 23:18:02","status":"running"}
2019/04/11 23:18:02 remove /nicktming/writerLayer, err:remove /nicktming/writerLayer: device or resource busy
root@nicktming:~/go/src/github.com/nicktming/mydocker# 
root@nicktming:~/go/src/github.com/nicktming/mydocker# ./mydocker ps
ID                     NAME                   PID         STATUS      COMMAND     CREATED
15549958821549242021   15549958821549242021   28396       running     /bin/top    2019-04-11 23:18:02
root@nicktming:~/go/src/github.com/nicktming/mydocker# 
root@nicktming:~/go/src/github.com/nicktming/mydocker# ./mydocker run -d -name test /bin/top
2019/04/11 23:18:42 volume:[]
2019/04/11 23:18:42 rootPath:
2019/04/11 23:18:42 rootPath is empaty, set cmd.Dir by default: /nicktming/mnt
2019/04/11 23:18:42 mkdir /nicktming/busybox err:mkdir /nicktming/busybox: file exists, set cmd.Dir by default: /nicktming/mnt
2019/04/11 23:18:42 mkdir /nicktming/writerLayer err:mkdir /nicktming/writerLayer: file exists
2019/04/11 23:18:42 containerId:15549959221141642621
2019/04/11 23:18:42 jsonInfo:{"pid":"28451","id":"15549959221141642621","name":"test","command":"/bin/top","createTime":"2019-04-11 23:18:42","status":"running"}
2019/04/11 23:18:42 mount -f /nicktming/mnt, err:exit status 1
2019/04/11 23:18:42 remove /nicktming/writerLayer, err:remove /nicktming/writerLayer: device or resource busy
root@nicktming:~/go/src/github.com/nicktming/mydocker# ./mydocker ps
ID                     NAME                   PID         STATUS      COMMAND     CREATED
15549958821549242021   15549958821549242021   28396       running     /bin/top    2019-04-11 23:18:02
15549959221141642621   test                   28451       running     /bin/top    2019-04-11 23:18:42
root@nicktming:~/go/src/github.com/nicktming/mydocker# 
root@nicktming:~/go/src/github.com/nicktming/mydocker# tree /var/run/mydocker/
/var/run/mydocker/
|-- 15549958821549242021
|   `-- config.json
`-- test
    `-- config.json

2 directories, 2 files

    可以看到列出了所有正在运行的容器.

    4. 时序图

    图片.png
    图片.png

    5. 参考

    1. 自己动手写docker.(基本参考此书,加入一些自己的理解,加深对docker的理解)

    6. 全部内容

    mydocker.png

    1. [mydocker]---环境说明
    2. [mydocker]---urfave cli 理解
    3. [mydocker]---Linux Namespace
    4. [mydocker]---Linux Cgroup
    5. [mydocker]---构造容器01-实现run命令
    6. [mydocker]---构造容器02-实现资源限制01
    7. [mydocker]---构造容器02-实现资源限制02
    8. [mydocker]---构造容器03-实现增加管道
    9. [mydocker]---通过例子理解存储驱动AUFS
    10. [mydocker]---通过例子理解chroot 和 pivot_root
    11. [mydocker]---一步步实现使用busybox创建容器
    12. [mydocker]---一步步实现使用AUFS包装busybox
    13. [mydocker]---一步步实现volume操作
    14. [mydocker]---实现保存镜像
    15. [mydocker]---实现容器的后台运行
    16. [mydocker]---实现查看运行中容器
    17. [mydocker]---实现查看容器日志
    18. [mydocker]---实现进入容器Namespace
    19. [mydocker]---实现停止容器
    20. [mydocker]---实现删除容器
    21. [mydocker]---实现容器层隔离
    22. [mydocker]---实现通过容器制作镜像
    23. [mydocker]---实现cp操作
    24. [mydocker]---实现容器指定环境变量
    25. [mydocker]---网际协议IP
    26. [mydocker]---网络虚拟设备veth bridge iptables
    27. [mydocker]---docker的四种网络模型与原理实现(1)
    28. [mydocker]---docker的四种网络模型与原理实现(2)
    29. [mydocker]---容器地址分配
    30. [mydocker]---网络net/netlink api 使用解析
    31. [mydocker]---网络实现
    32. [mydocker]---网络实现测试

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