/usr/share/gocode/src/github.com/mesos/mesos-go/messenger/messenger.go is in golang-github-mesos-mesos-go-dev 0.0.2+dfsg-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 of the 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 specific language governing permissions and
* limitations under the License.
*/
package messenger
import (
"fmt"
"net"
"reflect"
"strconv"
"sync"
"github.com/gogo/protobuf/proto"
log "github.com/golang/glog"
mesos "github.com/mesos/mesos-go/mesosproto"
"github.com/mesos/mesos-go/mesosutil/process"
"github.com/mesos/mesos-go/upid"
"golang.org/x/net/context"
)
const (
defaultQueueSize = 1024
)
// MessageHandler is the callback of the message. When the callback
// is invoked, the sender's upid and the message is passed to the callback.
type MessageHandler func(from *upid.UPID, pbMsg proto.Message)
// Messenger defines the interfaces that should be implemented.
type Messenger interface {
Install(handler MessageHandler, msg proto.Message) error
Send(ctx context.Context, upid *upid.UPID, msg proto.Message) error
Route(ctx context.Context, from *upid.UPID, msg proto.Message) error
Start() error
Stop() error
UPID() upid.UPID
}
// MesosMessenger is an implementation of the Messenger interface.
type MesosMessenger struct {
upid upid.UPID
encodingQueue chan *Message
sendingQueue chan *Message
installedMessages map[string]reflect.Type
installedHandlers map[string]MessageHandler
stop chan struct{}
stopOnce sync.Once
tr Transporter
}
// ForHostname creates a new default messenger (HTTP), using UPIDBindingAddress to
// determine the binding-address used for both the UPID.Host and Transport binding address.
func ForHostname(proc *process.Process, hostname string, bindingAddress net.IP, port uint16, publishedAddress net.IP) (Messenger, error) {
upid := upid.UPID{
ID: proc.Label(),
Port: strconv.Itoa(int(port)),
}
host, err := UPIDBindingAddress(hostname, bindingAddress)
if err != nil {
return nil, err
}
var publishedHost string
if publishedAddress != nil {
publishedHost, err = UPIDBindingAddress(hostname, publishedAddress)
if err != nil {
return nil, err
}
}
if publishedHost != "" {
upid.Host = publishedHost
} else {
upid.Host = host
}
return NewHttpWithBindingAddress(upid, bindingAddress), nil
}
// UPIDBindingAddress determines the value of UPID.Host that will be used to build
// a Transport. If a non-nil, non-wildcard bindingAddress is specified then it will be used
// for both the UPID and Transport binding address. Otherwise hostname is resolved to an IP
// address and the UPID.Host is set to that address and the bindingAddress is passed through
// to the Transport.
func UPIDBindingAddress(hostname string, bindingAddress net.IP) (string, error) {
upidHost := ""
if bindingAddress != nil && "0.0.0.0" != bindingAddress.String() {
upidHost = bindingAddress.String()
} else {
if hostname == "" || hostname == "0.0.0.0" {
return "", fmt.Errorf("invalid hostname (%q) specified with binding address %v", hostname, bindingAddress)
}
ip := net.ParseIP(hostname)
if ip != nil {
ip = ip.To4()
}
if ip == nil {
ips, err := net.LookupIP(hostname)
if err != nil {
return "", err
}
// try to find an ipv4 and use that
for _, addr := range ips {
if ip = addr.To4(); ip != nil {
break
}
}
if ip == nil {
// no ipv4? best guess, just take the first addr
if len(ips) > 0 {
ip = ips[0]
log.Warningf("failed to find an IPv4 address for '%v', best guess is '%v'", hostname, ip)
} else {
return "", fmt.Errorf("failed to determine IP address for host '%v'", hostname)
}
}
}
upidHost = ip.String()
}
return upidHost, nil
}
// NewMesosMessenger creates a new mesos messenger.
func NewHttp(upid upid.UPID) *MesosMessenger {
return NewHttpWithBindingAddress(upid, nil)
}
func NewHttpWithBindingAddress(upid upid.UPID, address net.IP) *MesosMessenger {
return New(upid, NewHTTPTransporter(upid, address))
}
func New(upid upid.UPID, t Transporter) *MesosMessenger {
return &MesosMessenger{
encodingQueue: make(chan *Message, defaultQueueSize),
sendingQueue: make(chan *Message, defaultQueueSize),
installedMessages: make(map[string]reflect.Type),
installedHandlers: make(map[string]MessageHandler),
tr: t,
}
}
/// Install installs the handler with the given message.
func (m *MesosMessenger) Install(handler MessageHandler, msg proto.Message) error {
// Check if the message is a pointer.
mtype := reflect.TypeOf(msg)
if mtype.Kind() != reflect.Ptr {
return fmt.Errorf("Message %v is not a Ptr type", msg)
}
// Check if the message is already installed.
name := getMessageName(msg)
if _, ok := m.installedMessages[name]; ok {
return fmt.Errorf("Message %v is already installed", name)
}
m.installedMessages[name] = mtype.Elem()
m.installedHandlers[name] = handler
m.tr.Install(name)
return nil
}
// Send puts a message into the outgoing queue, waiting to be sent.
// With buffered channels, this will not block under moderate throughput.
// When an error is generated, the error can be communicated by placing
// a message on the incoming queue to be handled upstream.
func (m *MesosMessenger) Send(ctx context.Context, upid *upid.UPID, msg proto.Message) error {
if upid == nil {
panic("cannot sent a message to a nil pid")
} else if *upid == m.upid {
return fmt.Errorf("Send the message to self")
}
name := getMessageName(msg)
log.V(2).Infof("Sending message %v to %v\n", name, upid)
select {
case <-ctx.Done():
return ctx.Err()
case m.encodingQueue <- &Message{upid, name, msg, nil}:
return nil
}
}
// Route puts a message either in the incoming or outgoing queue.
// This method is useful for:
// 1) routing internal error to callback handlers
// 2) testing components without starting remote servers.
func (m *MesosMessenger) Route(ctx context.Context, upid *upid.UPID, msg proto.Message) error {
if upid == nil {
panic("cannot route a message to a nil pid")
} else if *upid != m.upid {
// if destination is not self, send to outbound.
return m.Send(ctx, upid, msg)
}
// TODO(jdef) this has an unfortunate performance impact for self-messaging. implement
// something more reasonable here.
data, err := proto.Marshal(msg)
if err != nil {
return err
}
name := getMessageName(msg)
return m.tr.Inject(ctx, &Message{upid, name, msg, data})
}
// Start starts the messenger; expects to be called once and only once.
func (m *MesosMessenger) Start() error {
m.stop = make(chan struct{})
pid, errChan := m.tr.Start()
if pid == (upid.UPID{}) {
err := <-errChan
return fmt.Errorf("failed to start messenger: %v", err)
}
// the pid that we're actually bound as
m.upid = pid
go m.sendLoop()
go m.encodeLoop()
go m.decodeLoop()
// wait for a listener error or a stop signal; either way stop the messenger
// TODO(jdef) a better implementation would attempt to re-listen; need to coordinate
// access to m.upid in that case. probably better off with a state machine instead of
// what we have now.
go func() {
select {
case err := <-errChan:
if err != nil {
//TODO(jdef) should the driver abort in this case? probably
//since this messenger will never attempt to re-establish the
//transport
log.Errorln("transport stopped unexpectedly:", err.Error())
}
err = m.Stop()
if err != nil && err != errTerminal {
log.Errorln("failed to stop messenger cleanly: ", err.Error())
}
case <-m.stop:
}
}()
return nil
}
// Stop stops the messenger and clean up all the goroutines.
func (m *MesosMessenger) Stop() (err error) {
m.stopOnce.Do(func() {
select {
case <-m.stop:
default:
defer close(m.stop)
}
log.Info("stopping messenger..")
//TODO(jdef) don't hardcode the graceful flag here
if err2 := m.tr.Stop(true); err2 != nil && err2 != errTerminal {
log.Warningf("failed to stop the transporter: %v\n", err2)
err = err2
}
})
return
}
// UPID returns the upid of the messenger.
func (m *MesosMessenger) UPID() upid.UPID {
return m.upid
}
func (m *MesosMessenger) encodeLoop() {
for {
select {
case <-m.stop:
return
case msg := <-m.encodingQueue:
e := func() error {
//TODO(jdef) implement timeout for context
ctx, cancel := context.WithCancel(context.TODO())
defer cancel()
b, err := proto.Marshal(msg.ProtoMessage)
if err != nil {
return err
}
msg.Bytes = b
select {
case <-ctx.Done():
return ctx.Err()
case m.sendingQueue <- msg:
return nil
}
}()
if e != nil {
m.reportError(fmt.Errorf("Failed to enqueue message %v: %v", msg, e))
}
}
}
}
func (m *MesosMessenger) reportError(err error) {
log.V(2).Info(err)
//TODO(jdef) implement timeout for context
ctx, cancel := context.WithCancel(context.TODO())
defer cancel()
c := make(chan error, 1)
pid := m.upid
go func() { c <- m.Route(ctx, &pid, &mesos.FrameworkErrorMessage{Message: proto.String(err.Error())}) }()
select {
case <-ctx.Done():
<-c // wait for Route to return
case e := <-c:
if e != nil {
log.Errorf("failed to report error %v due to: %v", err, e)
}
}
}
func (m *MesosMessenger) sendLoop() {
for {
select {
case <-m.stop:
return
case msg := <-m.sendingQueue:
e := func() error {
//TODO(jdef) implement timeout for context
ctx, cancel := context.WithCancel(context.TODO())
defer cancel()
c := make(chan error, 1)
go func() { c <- m.tr.Send(ctx, msg) }()
select {
case <-ctx.Done():
// Transport layer must use the context to detect cancelled requests.
<-c // wait for Send to return
return ctx.Err()
case err := <-c:
return err
}
}()
if e != nil {
m.reportError(fmt.Errorf("Failed to send message %v: %v", msg.Name, e))
}
}
}
}
// Since HTTPTransporter.Recv() is already buffered, so we don't need a 'recvLoop' here.
func (m *MesosMessenger) decodeLoop() {
for {
select {
case <-m.stop:
return
default:
}
msg, err := m.tr.Recv()
if err != nil {
if err == discardOnStopError {
log.V(1).Info("exiting decodeLoop, transport shutting down")
return
} else {
panic(fmt.Sprintf("unexpected transport error: %v", err))
}
}
log.V(2).Infof("Receiving message %v from %v\n", msg.Name, msg.UPID)
msg.ProtoMessage = reflect.New(m.installedMessages[msg.Name]).Interface().(proto.Message)
if err := proto.Unmarshal(msg.Bytes, msg.ProtoMessage); err != nil {
log.Errorf("Failed to unmarshal message %v: %v\n", msg, err)
continue
}
// TODO(yifan): Catch panic.
m.installedHandlers[msg.Name](msg.UPID, msg.ProtoMessage)
}
}
// getMessageName returns the name of the message in the mesos manner.
func getMessageName(msg proto.Message) string {
return fmt.Sprintf("%v.%v", "mesos.internal", reflect.TypeOf(msg).Elem().Name())
}
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