使用 Docker Engine SDK 和 Docker API 的示例

在您安装 Docker 后，您可以安装 Go 或 Python SDK，还可以尝试 Docker Engine API。

这些示例分别展示了如何使用 Go 和 Python SDK 以及通过 curl 使用 HTTP API 来执行特定的 Docker 操作。

运行容器

第一个示例展示了如何使用 Docker API 运行容器。在命令行中，您会使用 docker run 命令，但这在您自己的应用程序中也很容易实现。

这相当于在命令提示符下输入 docker run alpine echo hello world

package main

import (
	"context"
	"io"
	"os"

	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/image"
	"github.com/docker/docker/client"
	"github.com/docker/docker/pkg/stdcopy"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	reader, err := cli.ImagePull(ctx, "docker.io/library/alpine", image.PullOptions{})
	if err != nil {
		panic(err)
	}

	defer reader.Close()
	// cli.ImagePull is asynchronous.
	// The reader needs to be read completely for the pull operation to complete.
	// If stdout is not required, consider using io.Discard instead of os.Stdout.
	io.Copy(os.Stdout, reader)

	resp, err := cli.ContainerCreate(ctx, &container.Config{
		Image: "alpine",
		Cmd:   []string{"echo", "hello world"},
		Tty:   false,
	}, nil, nil, nil, "")
	if err != nil {
		panic(err)
	}

	if err := cli.ContainerStart(ctx, resp.ID, container.StartOptions{}); err != nil {
		panic(err)
	}

	statusCh, errCh := cli.ContainerWait(ctx, resp.ID, container.WaitConditionNotRunning)
	select {
	case err := <-errCh:
		if err != nil {
			panic(err)
		}
	case <-statusCh:
	}

	out, err := cli.ContainerLogs(ctx, resp.ID, container.LogsOptions{ShowStdout: true})
	if err != nil {
		panic(err)
	}

	stdcopy.StdCopy(os.Stdout, os.Stderr, out)
}

$ curl --unix-socket /var/run/docker.sock -H "Content-Type: application/json" \
  -d '{"Image": "alpine", "Cmd": ["echo", "hello world"]}' \
  -X POST http://localhost/v1.49/containers/create
{"Id":"1c6594faf5","Warnings":null}

$ curl --unix-socket /var/run/docker.sock -X POST http://localhost/v1.49/containers/1c6594faf5/start

$ curl --unix-socket /var/run/docker.sock -X POST http://localhost/v1.49/containers/1c6594faf5/wait
{"StatusCode":0}

$ curl --unix-socket /var/run/docker.sock "http://localhost/v1.49/containers/1c6594faf5/logs?stdout=1"
hello world

当使用 cURL 通过 Unix socket 连接时，主机名并不重要。前面的示例使用了 localhost，但任何主机名都可以。

重要提示
前面的示例假设您正在使用 cURL 7.50.0 或更高版本。旧版本的 cURL 在使用 socket 连接时使用了非标准 URL 表示法。
如果您使用的是旧版本的 cURL，请改用 http:/<API version>/，例如：http:/v1.49/containers/1c6594faf5/start。

在后台运行容器

您还可以在后台运行容器，这相当于输入 docker run -d bfirsh/reticulate-splines

package main

import (
	"context"
	"fmt"
	"io"
	"os"

	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/image"
	"github.com/docker/docker/client"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	imageName := "bfirsh/reticulate-splines"

	out, err := cli.ImagePull(ctx, imageName, image.PullOptions{})
	if err != nil {
		panic(err)
	}
	defer out.Close()
	io.Copy(os.Stdout, out)

	resp, err := cli.ContainerCreate(ctx, &container.Config{
		Image: imageName,
	}, nil, nil, nil, "")
	if err != nil {
		panic(err)
	}

	if err := cli.ContainerStart(ctx, resp.ID, container.StartOptions{}); err != nil {
		panic(err)
	}

	fmt.Println(resp.ID)
}

$ curl --unix-socket /var/run/docker.sock -H "Content-Type: application/json" \
  -d '{"Image": "bfirsh/reticulate-splines"}' \
  -X POST http://localhost/v1.49/containers/create
{"Id":"1c6594faf5","Warnings":null}

$ curl --unix-socket /var/run/docker.sock -X POST http://localhost/v1.49/containers/1c6594faf5/start

列出和管理容器

您可以使用 API 列出正在运行的容器，就像使用 docker ps 一样

package main

import (
	"context"
	"fmt"

	containertypes "github.com/docker/docker/api/types/container"
	"github.com/docker/docker/client"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	containers, err := cli.ContainerList(ctx, containertypes.ListOptions{})
	if err != nil {
		panic(err)
	}

	for _, container := range containers {
		fmt.Println(container.ID)
	}
}

$ curl --unix-socket /var/run/docker.sock http://localhost/v1.49/containers/json
[{
  "Id":"ae63e8b89a26f01f6b4b2c9a7817c31a1b6196acf560f66586fbc8809ffcd772",
  "Names":["/tender_wing"],
  "Image":"bfirsh/reticulate-splines",
  ...
}]

停止所有正在运行的容器

既然您知道存在哪些容器，就可以对它们执行操作了。此示例将停止所有正在运行的容器。

注意
不要在生产服务器上运行此操作。此外，如果您正在使用 swarm services，容器会停止，但 Docker 会创建新的容器以保持服务按其配置状态运行。

package main

import (
	"context"
	"fmt"

	containertypes "github.com/docker/docker/api/types/container"
	"github.com/docker/docker/client"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	containers, err := cli.ContainerList(ctx, containertypes.ListOptions{})
	if err != nil {
		panic(err)
	}

	for _, container := range containers {
		fmt.Print("Stopping container ", container.ID[:10], "... ")
		noWaitTimeout := 0 // to not wait for the container to exit gracefully
		if err := cli.ContainerStop(ctx, container.ID, containertypes.StopOptions{Timeout: &noWaitTimeout}); err != nil {
			panic(err)
		}
		fmt.Println("Success")
	}
}

$ curl --unix-socket /var/run/docker.sock http://localhost/v1.49/containers/json
[{
  "Id":"ae63e8b89a26f01f6b4b2c9a7817c31a1b6196acf560f66586fbc8809ffcd772",
  "Names":["/tender_wing"],
  "Image":"bfirsh/reticulate-splines",
  ...
}]

$ curl --unix-socket /var/run/docker.sock \
  -X POST http://localhost/v1.49/containers/ae63e8b89a26/stop

打印特定容器的日志

您还可以对单个容器执行操作。此示例打印给定 ID 的容器的日志。在运行代码之前，您需要修改它，将硬编码的容器 ID 更改为要打印日志的容器 ID。

package main

import (
	"context"
	"io"
	"os"

	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/client"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	options := container.LogsOptions{ShowStdout: true}
	// Replace this ID with a container that really exists
	out, err := cli.ContainerLogs(ctx, "f1064a8a4c82", options)
	if err != nil {
		panic(err)
	}

	io.Copy(os.Stdout, out)
}

$ curl --unix-socket /var/run/docker.sock "http://localhost/v1.49/containers/ca5f55cdb/logs?stdout=1"
Reticulating spline 1...
Reticulating spline 2...
Reticulating spline 3...
Reticulating spline 4...
Reticulating spline 5...

列出所有镜像

列出 Engine 上的镜像，类似于 docker image ls

package main

import (
	"context"
	"fmt"

	"github.com/docker/docker/api/types/image"
	"github.com/docker/docker/client"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	images, err := cli.ImageList(ctx, image.ListOptions{})
	if err != nil {
		panic(err)
	}

	for _, image := range images {
		fmt.Println(image.ID)
	}
}

$ curl --unix-socket /var/run/docker.sock http://localhost/v1.49/images/json
[{
  "Id":"sha256:31d9a31e1dd803470c5a151b8919ef1988ac3efd44281ac59d43ad623f275dcd",
  "ParentId":"sha256:ee4603260daafe1a8c2f3b78fd760922918ab2441cbb2853ed5c439e59c52f96",
  ...
}]

拉取镜像

拉取镜像，例如 docker pull

package main

import (
	"context"
	"io"
	"os"

	"github.com/docker/docker/api/types/image"
	"github.com/docker/docker/client"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	out, err := cli.ImagePull(ctx, "alpine", image.PullOptions{})
	if err != nil {
		panic(err)
	}

	defer out.Close()

	io.Copy(os.Stdout, out)
}

$ curl --unix-socket /var/run/docker.sock \
  -X POST "http://localhost/v1.49/images/create?fromImage=alpine"
{"status":"Pulling from library/alpine","id":"3.1"}
{"status":"Pulling fs layer","progressDetail":{},"id":"8f13703509f7"}
{"status":"Downloading","progressDetail":{"current":32768,"total":2244027},"progress":"[\u003e                                                  ] 32.77 kB/2.244 MB","id":"8f13703509f7"}
...

带认证信息拉取镜像

拉取镜像，例如 docker pull，带认证信息

注意
凭证以明文形式发送。Docker 官方仓库使用 HTTPS。私有仓库也应配置为使用 HTTPS。

package main

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"io"
	"os"

	"github.com/docker/docker/api/types/image"
	"github.com/docker/docker/api/types/registry"
	"github.com/docker/docker/client"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	authConfig := registry.AuthConfig{
		Username: "username",
		Password: "password",
	}
	encodedJSON, err := json.Marshal(authConfig)
	if err != nil {
		panic(err)
	}
	authStr := base64.URLEncoding.EncodeToString(encodedJSON)

	out, err := cli.ImagePull(ctx, "alpine", image.PullOptions{RegistryAuth: authStr})
	if err != nil {
		panic(err)
	}

	defer out.Close()
	io.Copy(os.Stdout, out)
}

Python SDK 从凭证存储文件检索认证信息，并与凭证助手集成。可以覆盖这些凭证，但这超出了本示例指南的范围。在使用 docker login 后，Python SDK 会自动使用这些凭证。

import docker
client = docker.from_env()
image = client.images.pull("alpine")
print(image.id)

此示例会将凭证留在您的 shell 历史记录中，因此这被认为是一个简单的实现方式。凭证以 Base-64 编码的 JSON 结构传递。

$ JSON=$(echo '{"username": "string", "password": "string", "serveraddress": "string"}' | base64)

$ curl --unix-socket /var/run/docker.sock \
  -H "Content-Type: application/tar"
  -X POST "http://localhost/v1.49/images/create?fromImage=alpine"
  -H "X-Registry-Auth"
  -d "$JSON"
{"status":"Pulling from library/alpine","id":"3.1"}
{"status":"Pulling fs layer","progressDetail":{},"id":"8f13703509f7"}
{"status":"Downloading","progressDetail":{"current":32768,"total":2244027},"progress":"[\u003e                                                  ] 32.77 kB/2.244 MB","id":"8f13703509f7"}
...

提交容器

提交容器以从其内容创建镜像

package main

import (
	"context"
	"fmt"

	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/client"
)

func main() {
	ctx := context.Background()
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		panic(err)
	}
	defer cli.Close()

	createResp, err := cli.ContainerCreate(ctx, &container.Config{
		Image: "alpine",
		Cmd:   []string{"touch", "/helloworld"},
	}, nil, nil, nil, "")
	if err != nil {
		panic(err)
	}

	if err := cli.ContainerStart(ctx, createResp.ID, container.StartOptions{}); err != nil {
		panic(err)
	}

	statusCh, errCh := cli.ContainerWait(ctx, createResp.ID, container.WaitConditionNotRunning)
	select {
	case err := <-errCh:
		if err != nil {
			panic(err)
		}
	case <-statusCh:
	}

	commitResp, err := cli.ContainerCommit(ctx, createResp.ID, container.CommitOptions{Reference: "helloworld"})
	if err != nil {
		panic(err)
	}

	fmt.Println(commitResp.ID)
}

$ docker run -d alpine touch /helloworld
0888269a9d584f0fa8fc96b3c0d8d57969ceea3a64acf47cd34eebb4744dbc52
$ curl --unix-socket /var/run/docker.sock\
  -X POST "http://localhost/v1.49/commit?container=0888269a9d&repo=helloworld"
{"Id":"sha256:6c86a5cd4b87f2771648ce619e319f3e508394b5bfc2cdbd2d60f59d52acda6c"}