dotcloud/docker

package plugin // import "github.com/docker/docker/plugin"

import (
    "fmt"
    "reflect"

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

// Event is emitted for actions performed on the plugin manager
type Event interface {
    matches(Event) bool
}

// EventCreate is an event which is emitted when a plugin is created
// This is either by pull or create from context.
//
// Use the `Interfaces` field to match only plugins that implement a specific
// interface.
// These are matched against using "or" logic.
// If no interfaces are listed, all are matched.
type EventCreate struct {
    Interfaces map[string]bool
    Plugin     types.Plugin
}

func (e EventCreate) matches(observed Event) bool {
    oe, ok := observed.(EventCreate)
    if !ok {
        return false
    }
    if len(e.Interfaces) == 0 {
        return true
    }

    var ifaceMatch bool
    for _, in := range oe.Plugin.Config.Interface.Types {
        if e.Interfaces[in.Capability] {
            ifaceMatch = true
            break
        }
    }
    return ifaceMatch
}

// EventRemove is an event which is emitted when a plugin is removed
// It matches on the passed in plugin's ID only.
type EventRemove struct {
    Plugin types.Plugin
}

func (e EventRemove) matches(observed Event) bool {
    oe, ok := observed.(EventRemove)
    if !ok {
        return false
    }
    return e.Plugin.ID == oe.Plugin.ID
}

// EventDisable is an event that is emitted when a plugin is disabled
// It matches on the passed in plugin's ID only.
type EventDisable struct {
    Plugin types.Plugin
}

func (e EventDisable) matches(observed Event) bool {
    oe, ok := observed.(EventDisable)
    if !ok {
        return false
    }
    return e.Plugin.ID == oe.Plugin.ID
}

// EventEnable is an event that is emitted when a plugin is disabled
// It matches on the passed in plugin's ID only.
type EventEnable struct {
    Plugin types.Plugin
}

func (e EventEnable) matches(observed Event) bool {
    oe, ok := observed.(EventEnable)
    if !ok {
        return false
    }
    return e.Plugin.ID == oe.Plugin.ID
}

// SubscribeEvents provides an event channel to listen for structured events from
// the plugin manager actions, CRUD operations.
// The caller must call the returned `cancel()` function once done with the channel
// or this will leak resources.
func (pm *Manager) SubscribeEvents(buffer int, watchEvents ...Event) (eventCh <-chan interface{}, cancel func()) {
    topic := func(i interface{}) bool {
        observed, ok := i.(Event)
        if !ok {
            panic(fmt.Sprintf("unexpected type passed to event channel: %v", reflect.TypeOf(i)))
        }
        for _, e := range watchEvents {
            if e.matches(observed) {
                return true
            }
        }
        // If no specific events are specified always assume a matched event
        // If some events were specified and none matched above, then the event
        // doesn't match
        return watchEvents == nil
    }
    ch := pm.publisher.SubscribeTopicWithBuffer(topic, buffer)
    cancelFunc := func() { pm.publisher.Evict(ch) }
    return ch, cancelFunc
}