/
server.go
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/
server.go
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/*
* Copyright (C) 2019 Red Hat, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy ofthe License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specificlanguage governing permissions and
* limitations under the License.
*
*/
package server
import (
"encoding/json"
"errors"
"fmt"
"net/http"
"github.com/safchain/insanelock"
"github.com/skydive-project/skydive/graffiti/api/rest"
"github.com/skydive-project/skydive/graffiti/graph"
"github.com/skydive-project/skydive/graffiti/logging"
"github.com/skydive-project/skydive/graffiti/ondemand"
ws "github.com/skydive-project/skydive/graffiti/websocket"
)
type activeTask struct {
graph *graph.Graph
node *graph.Node
resource rest.Resource
task ondemand.Task
handler OnDemandServerHandler
}
// OnDemandServer describes an ondemand task server based on websocket
type OnDemandServer struct {
insanelock.RWMutex
graph.DefaultGraphListener
ws.DefaultSpeakerEventHandler
Graph *graph.Graph
clientPool *ws.StructClientPool
activeTasks map[graph.Identifier]map[string]*activeTask
wsNamespace string
resourceName string
handler OnDemandServerHandler
}
// OnDemandServerHandler is the interface to be implemented by ondemand servers
type OnDemandServerHandler interface {
ResourceName() string
DecodeMessage(msg json.RawMessage) (rest.Resource, error)
CreateTask(*graph.Node, rest.Resource) (interface{}, error)
RemoveTask(*graph.Node, rest.Resource, interface{}) error
}
// ErrTaskNotFound used when a task is not found for a specific node
var ErrTaskNotFound = errors.New("task not found")
func (o *OnDemandServer) registerTask(n *graph.Node, resource rest.Resource) bool {
logging.GetLogger().Debugf("Attempting to register %s %s on node %s", o.resourceName, resource.GetID(), n.ID)
if _, err := n.GetFieldString("Type"); err != nil {
logging.GetLogger().Infof("Unable to register task type of node unknown %v", n)
return false
}
o.Lock()
defer o.Unlock()
if tasks, active := o.activeTasks[n.ID]; active {
if _, found := tasks[resource.GetID()]; found {
logging.GetLogger().Debugf("A task already exists for %s on node %s", resource.GetID(), n.ID)
return false
}
}
task, err := o.handler.CreateTask(n, resource)
if err != nil {
logging.GetLogger().Errorf("Failed to register %s task: %s", o.resourceName, err)
return false
}
active := &activeTask{
graph: o.Graph,
node: n,
resource: resource,
task: task,
handler: o.handler,
}
if _, found := o.activeTasks[n.ID]; !found {
o.activeTasks[n.ID] = make(map[string]*activeTask)
}
o.activeTasks[n.ID][resource.GetID()] = active
logging.GetLogger().Debugf("New active task on: %v (%v)", n, resource)
return true
}
// unregisterTask should be executed under graph lock
func (o *OnDemandServer) unregisterTask(n *graph.Node, resource rest.Resource) error {
o.RLock()
var active *activeTask
tasks, isActive := o.activeTasks[n.ID]
if isActive {
active, isActive = tasks[resource.GetID()]
}
o.RUnlock()
if !isActive {
return ErrTaskNotFound
}
name, _ := n.GetFieldString("Name")
logging.GetLogger().Debugf("Attempting to unregister task on node %s (%s)", name, n.ID)
if err := o.handler.RemoveTask(n, active.resource, active.task); err != nil {
return err
}
o.Lock()
if tasks, found := o.activeTasks[n.ID]; found {
delete(tasks, resource.GetID())
}
if len(o.activeTasks[n.ID]) == 0 {
delete(o.activeTasks, n.ID)
}
o.Unlock()
return nil
}
// OnStructMessage websocket message, valid message type are Start, Stop
func (o *OnDemandServer) OnStructMessage(c ws.Speaker, msg *ws.StructMessage) {
var enveloppe ondemand.RawQuery
if err := json.Unmarshal(msg.Obj, &enveloppe); err != nil {
logging.GetLogger().Errorf("Unable to decode message %v", msg)
return
}
resource, err := o.handler.DecodeMessage(enveloppe.Resource)
if err != nil {
logging.GetLogger().Errorf("Unable to decode message %v", o.resourceName)
return
}
query := ondemand.Query{NodeID: enveloppe.NodeID, Resource: resource}
status := http.StatusBadRequest
o.Graph.Lock()
switch msg.Type {
case "Start":
n := o.Graph.GetNode(graph.Identifier(query.NodeID))
if n == nil {
logging.GetLogger().Errorf("Unknown node %s for new %s", query.NodeID, o.resourceName)
status = http.StatusNotFound
break
}
status = http.StatusOK
if _, err := n.GetFieldString(fmt.Sprintf("%s.ID", o.resourceName)); err == nil {
logging.GetLogger().Debugf("%s already started on node %s", n.ID, o.resourceName)
} else {
if ok := o.registerTask(n, resource); !ok {
status = http.StatusInternalServerError
}
}
case "Stop":
n := o.Graph.GetNode(graph.Identifier(query.NodeID))
if n == nil {
logging.GetLogger().Errorf("Unknown node %s for new %s", query.NodeID, o.resourceName)
status = http.StatusNotFound
break
}
status = http.StatusOK
if err := o.unregisterTask(n, resource); err != nil {
if err == ErrTaskNotFound {
logging.GetLogger().Warningf("Failed to unregister %s on node %s, %s", o.resourceName, n.ID, err)
status = http.StatusNotFound
} else {
logging.GetLogger().Errorf("Failed to unregister %s on node %s, %s", o.resourceName, n.ID, err)
status = http.StatusInternalServerError
}
}
}
// be sure to unlock before sending message
o.Graph.Unlock()
reply := msg.Reply(&query, msg.Type+"Reply", status)
c.SendMessage(reply)
}
// OnNodeDeleted graph event
func (o *OnDemandServer) OnNodeDeleted(n *graph.Node) {
o.RLock()
tasks, found := o.activeTasks[n.ID]
if found {
for _, task := range tasks {
capture := task.resource
defer func() {
if err := o.unregisterTask(n, capture); err != nil {
logging.GetLogger().Errorf("Failed to unregister %s %s on node %s", o.resourceName, capture.GetID(), n.ID)
}
}()
}
}
o.RUnlock()
}
// Start the task
func (o *OnDemandServer) Start() error {
o.Graph.AddEventListener(o)
o.clientPool.AddStructMessageHandler(o, []string{o.wsNamespace})
return nil
}
// Stop the task
func (o *OnDemandServer) Stop() {
o.Graph.RemoveEventListener(o)
o.Graph.Lock()
for _, tasks := range o.activeTasks {
for _, active := range tasks {
o.unregisterTask(active.node, active.resource)
}
}
o.Graph.Unlock()
}
// NewOnDemandServer creates a new Ondemand tasks server based on graph and websocket
func NewOnDemandServer(g *graph.Graph, pool *ws.StructClientPool, handler OnDemandServerHandler) (*OnDemandServer, error) {
return &OnDemandServer{
Graph: g,
clientPool: pool,
activeTasks: make(map[graph.Identifier]map[string]*activeTask),
wsNamespace: ondemand.Namespace + handler.ResourceName(),
resourceName: handler.ResourceName(),
handler: handler,
}, nil
}