Docker Engine SDKs and API 的开发1

Develop with Docker Engine SDKs and API

Docker provides an API for interacting with the Docker daemon (called the Docker Engine API), as well as SDKs for Go and Python. The SDKs allow you to build and scale Docker apps and solutions quickly and easily. If Go or Python don’t work for you, you can use the Docker Engine API directly.

The Docker Engine API is a RESTful API accessed by an HTTP client such as wget or curl, or the HTTP library which is part of most modern programming languages.

Install the SDKs

Use the following commands to install the Go or Python SDK.

Both SDKs can be installed and coexist together.

Go SDK

go get github.com/docker/docker/client

Read the full Docker Engine Go SDK reference.

Python SDK

• Recommended: Run pip install docker.

• If you can’t use pip:

  1. Download the package directly.
  2. Extract it and change to the extracted directory,
  3. Run python setup.py install.

Read the full Docker Engine Python SDK reference.

View the API reference

You can view the reference for the latest version of the API or choose a specific version.

Versioned API and SDK

The version of the Docker Engine API you should use depends upon the version of your Docker daemon and Docker client.

A given version of the Docker Engine SDK supports a specific version of the Docker Engine API, as well as all earlier versions. If breaking changes occur, they are documented prominently.

Daemon and client API mismatches

The Docker daemon and client do not necessarily need to be the same version at all times. However, keep the following in mind.

• If the daemon is newer than the client, the client does not know about new features or deprecated API endpoints in the daemon.

• If the client is newer than the daemon, the client can request API endpoints that the daemon does not know about.

A new version of the API is released when new features are added.

The Docker API is backward-compatible, so you do not need to update code that uses the API unless you need to take advantage of new features.

To see the highest version of the API your Docker daemon and client support, use docker version:

$ docker version

Client:
 Version:      17.04.0-ce
 API version:  1.28
 Go version:   go1.7.5
 Git commit:   4845c56
 Built:        Wed Apr  5 06:06:36 2017
 OS/Arch:      darwin/amd64

Server:
 Version:      17.04.0-ce
 API version:  1.28 (minimum version 1.12)
 Go version:   go1.7.5
 Git commit:   4845c56
 Built:        Tue Apr  4 00:37:25 2017
 OS/Arch:      linux/amd64
 Experimental: true

　　

You can specify the API version to use, in one of the following ways:

• When using the SDK, use the latest version you can, but at least the version that incorporates the API version with the features you need.

• When using curl directly, specify the version as the first part of the URL. For instance, if the endpoint is /containers/, you can use /v1.27/containers/.

• To force the Docker CLI or the Docker Engine SDKs to use an old version version of the API than the version reported by docker version, set the environment variable DOCKER_API_VERSION to the correct version. This works on Linux, Windows, or macOS clients.

  DOCKER_API_VERSION='1.27'

  While the environment variable is set, that version of the API is used, even if the Docker daemon supports a newer version.

• For the SDKs, you can also specify the API version programmatically, as a parameter to the client object. See the Go constructor or the Python SDK documentation for client.

Docker EE and CE API mismatch

If you use Docker EE in production, we recommend using Docker EE in development too.

If you can’t, such as when your developers use Docker for Mac or Docker for Windows and manually build and push images, then your developers need to configure their Docker clients to use the same version of the API reported by their Docker daemon. This prevents the developer from using a feature that is not yet supported on the daemon where the workload runs in production. You can do this one of two ways:

• Configure the Docker client to connect to an external daemon running Docker EE. You can use the -H flag on the docker command or set the DOCKER_HOST environment variable. The client uses the daemon’s latest supported API version.
• Configure the Docker client to use a specific API by setting the DOCKER_API_VERSION environment variable to the API version to use, such as 1.30.

API version matrix

Docker does not recommend running versions prior to 1.12, which means you are encouraged to use an API version of 1.24 or higher.

Docker version	Maximum API version	Change log
18.05	1.37	changes
18.04	1.37	changes
18.03	1.37	changes
18.02	1.36	changes
17.12	1.35	changes
17.11	1.34	changes
17.10	1.33	changes
17.09	1.32	changes
17.07	1.31	changes
17.06	1.30	changes
17.05	1.29	changes
17.04	1.28	changes
17.03.1	1.27	changes
17.03	1.26	changes
1.13.1	1.26	changes
1.13	1.25	changes
1.12	1.24	changes
1.11	1.23	changes
1.10	1.22	changes
1.9	1.21	changes
1.8	1.20	changes
1.7	1.19	changes
1.6	1.18	changes

Choose the SDK or API version to use

Use the following guidelines to choose the SDK or API version to use in your code:

• If you’re starting a new project, use the latest version, but do specify the version you are using. This helps prevent surprises.
• If you need a new feature, update your code to use at least the minimum version that supports the feature, and prefer the latest version you can use.
• Otherwise, continue to use the version that your code is already using.

SDK and API quickstart

As an example, the docker run command can be easily implemented using the Docker API directly, or using the Python or Go SDK.

Go：

package main

import (
    "io"
    "os"

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

    "golang.org/x/net/context"
)

func main() {
    ctx := context.Background()
    cli, err := client.NewEnvClient()
    if err != nil {
        panic(err)
    }

    _, err = cli.ImagePull(ctx, "docker.io/library/alpine", types.ImagePullOptions{})
    if err != nil {
        panic(err)
    }

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

    if err := cli.ContainerStart(ctx, resp.ID, types.ContainerStartOptions{}); 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, types.ContainerLogsOptions{ShowStdout: true})
    if err != nil {
        panic(err)
    }

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

　　

Python：

import docker
client = docker.from_env()
print client.containers.run("alpine", ["echo", "hello", "world"])

　　

HTTP：

$ curl --unix-socket /var/run/docker.sock -H "Content-Type: application/json" \
  -d '{"Image": "alpine", "Cmd": ["echo", "hello world"]}' \
  -X POST http:/v1.24/containers/create
{"Id":"1c6594faf5","Warnings":null}

$ curl --unix-socket /var/run/docker.sock -X POST http:/v1.24/containers/1c6594faf5/start

$ curl --unix-socket /var/run/docker.sock -X POST http:/v1.24/containers/1c6594faf5/wait
{"StatusCode":0}

$ curl --unix-socket /var/run/docker.sock "http:/v1.24/containers/1c6594faf5/logs?stdout=1"
hello world

　　

For more examples, take a look at the getting started guide.

Unofficial libraries

There are a number of community supported libraries available for other languages. They have not been tested by Docker, so if you run into any issues, file them with the library maintainers.

Language	Library
C	libdocker
C#	Docker.DotNet
C++	lasote/docker_client
Dart	bwu_docker
Erlang	erldocker
Gradle	gradle-docker-plugin
Groovy	docker-client
Haskell	docker-hs
HTML (Web Components)	docker-elements
Java	docker-client
Java	docker-java
Java	docker-java-api
NodeJS	dockerode
NodeJS	harbor-master
Perl	Eixo::Docker
PHP	Docker-PHP
Ruby	docker-api
Rust	docker-rust
Rust	shiplift
Scala	tugboat
Scala	reactive-docker
Swift	docker-client-swift