Task API

首先看一下关于Task API都有哪些接口， path在 containerd/api/services/tasks/v1/tasks.pb.go，

var _Tasks_serviceDesc = grpc.ServiceDesc{
    ServiceName: "containerd.services.tasks.v1.Tasks",
    HandlerType: (*TasksServer)(nil),
    Methods: []grpc.MethodDesc{
        {
            MethodName: "Create",
            Handler:    _Tasks_Create_Handler,
        },
        {
            MethodName: "Start",
            Handler:    _Tasks_Start_Handler,
        },
        {
            MethodName: "Delete",
            Handler:    _Tasks_Delete_Handler,
        },
        {
            MethodName: "DeleteProcess",
            Handler:    _Tasks_DeleteProcess_Handler,
        },
        {
            MethodName: "Get",
            Handler:    _Tasks_Get_Handler,
        },
        {
            MethodName: "List",
            Handler:    _Tasks_List_Handler,
        },
        {
            MethodName: "Kill",
            Handler:    _Tasks_Kill_Handler,
        },
        {
            MethodName: "Exec",
            Handler:    _Tasks_Exec_Handler,
        },
        {
            MethodName: "ResizePty",
            Handler:    _Tasks_ResizePty_Handler,
        },
        {  //关于容器I/O的部分我们后边会着重看一下
            MethodName: "CloseIO",
            Handler:    _Tasks_CloseIO_Handler,
        },
        {
            MethodName: "Pause",
            Handler:    _Tasks_Pause_Handler,
        },
        {
            MethodName: "Resume",
            Handler:    _Tasks_Resume_Handler,
        },
        {
            MethodName: "ListPids",
            Handler:    _Tasks_ListPids_Handler,
        },
        {
            MethodName: "Checkpoint",
            Handler:    _Tasks_Checkpoint_Handler,
        },
        {
            MethodName: "Update",
            Handler:    _Tasks_Update_Handler,
        },
        {
            MethodName: "Metrics",
            Handler:    _Tasks_Metrics_Handler,
        },
        {
            MethodName: "Wait",
            Handler:    _Tasks_Wait_Handler,
        },
    },
    Streams:  []grpc.StreamDesc{},
    Metadata: "github.com/containerd/containerd/api/services/tasks/v1/tasks.proto",
}

来看一下run一个容器的逻辑链路。

path: containerd/cmd/ctr/commands/run/run.go 具体代码的就不截图了，而实现的主要逻辑如下所示:

NewContainer -> c.ContainerService().Create(ctx, container)//创建container这个metadata
//其中还会针对是否有无checkpoint来进行区别

NewTask -> container.NewTask(ctx, ioCreator, opts...) -> c.client.TaskService().Create(ctx, request) //也验证了必须首先有container的metadata才能够创建，只有当Task被执行的时候才会创建一个真正的容器

task.Start(ctx)

//如果收到退出信号
task.Delete(ctx) 
//返回状态码