[docker] Docker Engine API(Docker daemon)

개요

• https://docs.docker.com/engine/api/
• 도커는 도커 데몬(Docker Engine API)과 상호 작용하기 위한 HTTP(RESTful) API와 SDK 제공
• SDK는 하위 버전 호환

HTTP API

• reference
  • latest
  • by version
• 호출 방법
  • unix socket
    • curl --unix-socket /var/run/docker.sock http://localhost/v1.41/images/json
  • ip
    • curl -X GET http://127.0.0.1:3000/v1.41/images/json

SDK

• Go
  • go get github.com/docker/docker/client
  • reference
• Python
  • pip install docker
  • reference
• Unofficial libraries
• SDK examples

도커 원격 접근 방법

• 도커는 기본적으로 유닉스 소켓으로 실행되므로 원격 접속을 위해선 호스트 추가가 필요
  • vim /lib/systemd/system/docker.service
    • ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock -H 0.0.0.0:3000
  • systemctl daemon-reload
  • systemctl restart docker

예제

• docker images
  • HTTP
    • curl -X GET http://127.0.0.1:3000/v1.41/images/json
  • SDK
    • Go

       package main
              
       import (
       	"context"
       	"fmt"
              
       	"github.com/docker/docker/api/types"
       	"github.com/docker/docker/client"
       )
              
       func main() {
       	ctx := context.Background()
       	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithHost("http://127.0.0.1:3000"), client.WithAPIVersionNegotiation())
       	if err != nil {
       		panic(err)
       	}
              
       	images, err := cli.ImageList(ctx, types.ImageListOptions{})
       	if err != nil {
       		panic(err)
       	}
              
       	for _, image := range images {
       		fmt.Println(image.ID)
       	}
       }
      

• docker run
  • HTTP
    • 이미지 풀
      • curl -X POST "http://127.0.0.1:3000/v1.41/images/create?fromImage=alpine:3.16.0"
    • 컨테이너 생성
      • curl -H "Content-Type: application/json" -d '{"Image": "alpine:3.16.0", "Cmd": ["echo", "hello world"]}' -X POST http://127.0.0.1:3000/v1.41/containers/create
        • 응답이 {"Id":"ac6594faf5","Warnings":[]}라 가정
    • 컨테이너 실행
      • curl -X POST http://127.0.0.1:3000/v1.41/containers/ac6594faf5/start
    • 컨테이너가 지정된 상태가 될 때까지 대기
      • curl -X POST "http://127.0.0.1:3000/v1.41/containers/ac6594faf5/wait?condition=not-running"
    • 컨테이너 로그
      • curl -X GET "http://127.0.0.1:3000/v1.41/containers/ac6594faf5/logs?stdout=1"
    • 컨테이너 삭제
      • curl -X DELETE http://127.0.0.1:3000/v1.41/containers/ac6594faf5
  • SDK
    • Go

       package main
              
       import (
       	"context"
       	"io"
       	"os"
              
       	"github.com/docker/docker/api/types"
       	"github.com/docker/docker/api/types/container"
       	"github.com/docker/docker/client"
       	"github.com/docker/docker/pkg/stdcopy"
       )
              
       func main() {
       	ctx := context.Background()
       	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithHost("http://127.0.0.1:3000"), client.WithAPIVersionNegotiation())
       	if err != nil {
       		panic(err)
       	}
              
       	// image pull
       	radCloser, err := cli.ImagePull(ctx, "alpine:3.16.0", types.ImagePullOptions{})
       	if err != nil {
       		panic(err)
       	}
       	defer radCloser.Close()
       	io.Copy(os.Stdout, radCloser)
              
       	// container create
       	resp, err := cli.ContainerCreate(ctx, &container.Config{
       		Image: "alpine:3.16.0",
       		Cmd:   []string{"echo", "hello world"},
       	}, nil, nil, nil, "")
       	if err != nil {
       		panic(err)
       	}
              
       	// container start
       	if err := cli.ContainerStart(ctx, resp.ID, types.ContainerStartOptions{}); err != nil {
       		panic(err)
       	}
              
       	// container wait
       	statusCh, errCh := cli.ContainerWait(ctx, resp.ID, container.WaitConditionNotRunning)
       	select {
       	case err := <-errCh:
       		if err != nil {
       			panic(err)
       		}
       	case <-statusCh:
       	}
              
       	// container log
       	radCloser, err = cli.ContainerLogs(ctx, resp.ID, types.ContainerLogsOptions{ShowStdout: true})
       	if err != nil {
       		panic(err)
       	}
       	stdcopy.StdCopy(os.Stdout, os.Stderr, radCloser)
              
       	// container remove
       	if err := cli.ContainerRemove(ctx, resp.ID, types.ContainerRemoveOptions{}); err != nil {
       		panic(err)
       	}
       }