package plugins

import "github.com/docker/cli/components/engine/pkg/plugins"

Package plugins provides structures and helper functions to manage Docker plugins.

Docker discovers plugins by looking for them in the plugin directory whenever a user or container tries to use one by name. UNIX domain socket files must be located under /run/docker/plugins, whereas spec files can be located either under /etc/docker/plugins or /usr/lib/docker/plugins. This is handled by the Registry interface, which lets you list all plugins or get a plugin by its name if it exists.

The plugins need to implement an HTTP server and bind this to the UNIX socket or the address specified in the spec files. A handshake is send at /Plugin.Activate, and plugins are expected to return a Manifest with a list of of Docker subsystems which this plugin implements.

In order to use a plugins, you can use the “Get“ with the name of the plugin and the subsystem it implements.

plugin, err := plugins.Get("example", "VolumeDriver")
if err != nil {
	return fmt.Errorf("Error looking up volume plugin example: %v", err)
}

Index ¶

• Variables
• func Handle(iface string, fn func(string, *Client))
• func IsNotFound(err error) bool
• func Scan() ([]string, error)
• type Client
• func NewClient(addr string, tlsConfig *tlsconfig.Options) (*Client, error)
• func NewClientWithTimeout(addr string, tlsConfig *tlsconfig.Options, timeout time.Duration) (*Client, error)
• func (c *Client) Call(serviceMethod string, args interface{}, ret interface{}) error
• func (c *Client) SendFile(serviceMethod string, data io.Reader, ret interface{}) error
• func (c *Client) Stream(serviceMethod string, args interface{}) (io.ReadCloser, error)
• type Manifest
• type Plugin
• func Get(name, imp string) (*Plugin, error)
• func GetAll(imp string) ([]*Plugin, error)
• func NewLocalPlugin(name, addr string) *Plugin
• func (p *Plugin) BasePath() string
• func (p *Plugin) Client() *Client
• func (p *Plugin) IsV1() bool
• func (p *Plugin) Name() string

Variables ¶

var (
	// ErrNotFound plugin not found
	ErrNotFound = errors.New("plugin not found")
)

var (
	// ErrNotImplements is returned if the plugin does not implement the requested driver.
	ErrNotImplements = errors.New("Plugin does not implement the requested driver")
)

Functions ¶

func Handle ¶

func Handle(iface string, fn func(string, *Client))

Handle adds the specified function to the extpointHandlers.

func IsNotFound ¶

func IsNotFound(err error) bool

IsNotFound indicates if the passed in error is from an http.StatusNotFound from the plugin

func Scan ¶

func Scan() ([]string, error)

Scan scans all the plugin paths and returns all the names it found

Types ¶

type Client ¶

type Client struct {
	// contains filtered or unexported fields
}

Client represents a plugin client.

func NewClient ¶

func NewClient(addr string, tlsConfig *tlsconfig.Options) (*Client, error)

NewClient creates a new plugin client (http).

func NewClientWithTimeout ¶

func NewClientWithTimeout(addr string, tlsConfig *tlsconfig.Options, timeout time.Duration) (*Client, error)

NewClientWithTimeout creates a new plugin client (http).

func (*Client) Call ¶

func (c *Client) Call(serviceMethod string, args interface{}, ret interface{}) error

Call calls the specified method with the specified arguments for the plugin. It will retry for 30 seconds if a failure occurs when calling.

func (*Client) SendFile ¶

func (c *Client) SendFile(serviceMethod string, data io.Reader, ret interface{}) error

SendFile calls the specified method, and passes through the IO stream

func (*Client) Stream ¶

func (c *Client) Stream(serviceMethod string, args interface{}) (io.ReadCloser, error)

Stream calls the specified method with the specified arguments for the plugin and returns the response body

type Manifest ¶

type Manifest struct {
	// List of subsystem the plugin implements.
	Implements []string
}

Manifest lists what a plugin implements.

type Plugin ¶

type Plugin struct {

	// Address of the plugin
	Addr string
	// TLS configuration of the plugin
	TLSConfig *tlsconfig.Options

	// Manifest of the plugin (see above)
	Manifest *Manifest `json:"-"`
	// contains filtered or unexported fields
}

Plugin is the definition of a docker plugin.

func Get ¶

func Get(name, imp string) (*Plugin, error)

Get returns the plugin given the specified name and requested implementation.

func GetAll ¶

func GetAll(imp string) ([]*Plugin, error)

GetAll returns all the plugins for the specified implementation

func NewLocalPlugin ¶

func NewLocalPlugin(name, addr string) *Plugin

NewLocalPlugin creates a new local plugin.

func (*Plugin) BasePath ¶

func (p *Plugin) BasePath() string

BasePath returns the path to which all paths returned by the plugin are relative to. For v1 plugins, this always returns the host's root directory.

func (*Plugin) Client ¶

func (p *Plugin) Client() *Client

Client returns a ready-to-use plugin client that can be used to communicate with the plugin.

func (*Plugin) IsV1 ¶

func (p *Plugin) IsV1() bool

IsV1 returns true for V1 plugins and false otherwise.

func (*Plugin) Name ¶

func (p *Plugin) Name() string

Name returns the name of the plugin.

Source Files ¶

client.go discovery.go discovery_unix.go errors.go plugins.go plugins_unix.go

Directories ¶